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214 Journal of Intellectual Disability - Diagnosis and Treatment, 2023, 11, 214-225
E-ISSN: 2292-2598/23
Cognitive Abilities in Schizoid Personality Disorder with and
without Borderline Intellectual Functioning: The Burden in
Psychopathology
D. Galletta1,*, C. Santoriello1, A.I. Califano1, I. Lauria1 and G. Santangelo2
1Care Department Time Dependent Network: Stroke, Surgical Emergencies and Trauma - Unit of Psychiatry
and Psychology, University Hospital of Naples “Federico II”, Italy
2Department of Psychology, University of Campania "Luigi Vanvitelli”, Caserta, Italy
Abstract: Background: Borderline intellect ual functioning (BIF) and schizoid personality disor der (Schiz oid PD) are
clinic al conditions under-researched and poorly understood. The principal aim of this retrospective study was to
investigate cognitive abilities in p eople with BIF and Schiz oid PD. Clinical, demographic, and neuropsychological data of
forty-seven Schizoid PD participants, with an average age of 35, were analyzed. The sample split into two groups:
Schizoid PD with BIF (BIF+: n = 24; intelligence quotient – IQ range: 71-84) and Schizoid PD without BIF (BIF-: n = 23;
IQ range: 89-121). A descriptive analysis of the clinical and demographic characteristics of the two groups was
performed.
Methods: Neuropsychological measures (Wechsler Adult Intelligence Scale-Revised – WAIS-R IQ, factor index, subtest
scores) and cognitive performance deficits in the two groups were compared using parametric and non-parametric tests,
as necessary. Correlation coefficients were calculated for relationships between var iables . Regression analyses were
conducted to identify predictors associated with negative outcomes, such as substance use behavior.
Results: The results revealed that the cognitive profile of BIF+ deviated significantly from that observed in BIF-. Peculiar
BIF+ dysfunctions were found in the domains of verbal and perceptual reasoning, attention, memory, processing speed,
planning, and problem-solving. The verbal IQ had the highest discriminative value for the presence of BIF in patients with
Schizoid PD.
Conclusions: The BIF condition and the verbal comprehension index were the predictors most associated with substance
use behavior. Early identification of BIF should b e relevant to planning targeted intervention strategies to improve daily
life skills and outcomes.
Keywords: Cognitive functions, Personality disorders, Adaptive functioning, Verbal comprehension,
Neuropsychological assessment, statistical analysis.
1. INTRODUCTION
Borderline intellectual functioning (BIF) is
characterized by an intelligence quotient (IQ) score that
ranges from 71 to 84, with difficulties in achieving
developmental milestones and an impact on adaptive
abilities for personal independence and social
responsibility [1, 2]. In the absence of a clear definition
of clinical, behavioral, and cognitive features of people
with BIF [3], they have often been unrecognized by
mental health professionals, receiving unneeded drug
treatments and little, if any, psychological, educational,
and social supports [4, 5]. Research has shown that
BIFs are a large high-risk group for adverse outcomes,
poor academic achievements [6], job insecurity [7], and
lack of social skills [8]. BIF is over-represented in the
criminal justice system [9, 10] and in the forensic
addiction treatment center [11, 12]. Several longitudinal
studies provide evidence that reduced intelligence
*Address correspondence to this author at the Car e Depart ment T ime
Dependent Network: Stroke, Surgical Emergencies and Trauma - Unit of
Psychiatry and Psychology, University Hospital of Naples “Federico II”, Italy;
E-mail: diana.galletta @unina.it
(low IQ) is a risk factor for the development of any
personality disorder (PD) as well as for hospital
admission and illness severity [4, 13,14]. In the
Diagnostic and Statistical Manuals of Mental Disorders
[1, 15], personality disorders (PDs) are described as
inflexible and enduring patterns of inner experience
and behavior that deviate markedly from the
expectations of the individual’s culture, and lead to
clinically significant distress or impairment in social,
occupational, or other important areas of functioning. In
the DSM system, PDs are grouped into three Clusters
based on phenotypic similarity: Cluster A includes odd
or eccentric individuals (paranoid, schizoid, and
schizotypal PDs); Cluster B includes dramatic,
emotional, or erratic individuals (antisocial, borderline,
histrionic, and narcissistic PDs); Cluster C includes
anxious or fearful individuals (avoidant, dependent, and
obsessive-compulsive PDs). Schizoid personality
disorder (Schizoid PD) is a pervasive pattern of
withdrawal and detachment from social relationships
with a tendency toward solitary lifestyle, indifference to
praise or criticism, emotional aloofness, lack of
motivation, and low interest in activities [1,16-18].
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 215
Although Schizoid PD patients are uncommon in
clinical settings, probably due to the predisposition of
these individuals to avoid social contact and
professional help, there is a higher prevalence of
Schizoid PD in the offender population [19]. The
literature review shows that Schizoid PD is strongly
related to substance abuse [20], violent crimes [21-23],
as well as features of psychopathy and violent
antisocial behavior [16, 24]. Poor parenting has been
associated with BIF [25], Schizoid PD [26, 27], with the
increased risk of substance use in BIF [28], and
Schizoid PD [29]. Furthermore, research has provided
evidence that exposure to adverse childhood
experiences (ACEs), parental socioeconomic
disadvantage (low SES), and the lack of appropriate
stimulation in family and school environments may
affect social cognitive development, increasing the risk
of educational failures, mental illnesses, substance use
and offending behaviors [27, 30-33].
To our knowledge, no prior studies have examined
cognitive abilities in young adults with borderline
intellectual functioning and schizoid personality
disorder. Nevertheless, our clinical experience with
these individuals has revealed their dramatic
impairment in daily functioning and social adaptation,
as well as persistent failures in meeting environmental
challenges. Cognitive abilities are inextricably linked to
emotion regulation, socio-affective skills, and
personality development [34-36]. According to the
literature, cognitive functioning may predict social
adaptation [37], mostly in individuals living in adverse
environments [38]. Furthermore, poor cognitive
resources such as lower IQ represent a general
vulnerability of the brain that increases the risk of
negative outcomes across the life span [39]. Available
studies on the cognitive features of individuals with BIF
have focused mostly on children and adolescents.
Although previous research has found comorbidity with
learning disabilities in children with BIF due to poorer
sustained attention, slower processing speed [40, 41],
and limited executive functioning [28, 42], their
difficulties are not confined to a specific domain [43].
Moreover, children with BIF showed problems with
abstract reasoning, verbal comprehension deficits [44],
and a lower capacity to generalize information from one
learning context to another [45]. Impaired adaptive
skills would seem to reflect general intellectual
functioning limitations with a lack of compensatory
strategies [46, 47], while the poor social abilities and
behavioral problems in BIF have been associated with
an inadequate system of Social Information Processing
[48-50] (SIP). The cognitive characteristics of Schizoid
PD individuals have been defined as “neuro-
psychological syndrome of adaption/dysadaptation”
[51], with a combination of executive dysregulation,
memory reduction, and spatial disorders [45]. In the
study of Hengartner et al. [52], the schizoid personality
disorder was related to slower information processing
speed associated with fluid intelligence and reduced
emotional empathy characterized by low willingness to
feel compassion for other people and high negativ e
feelings in reaction to others' emotional expressions. In
our previous study [53] investigating the cognitive
correlates of BIF in participants diagnosed with
borderline personality disorder (BPD) by using the
Italian version of the Wechsler Adult Intelligence Scale-
Revised – WAIS-R [54], we found that the verbal
intelligence quotient (VIQ) and the verbal
comprehension index (VC) had the highest
discriminative value for the presence of BIF in BPD. In
the current retrospective study, we aimed to explore
the cognitive profile of BIF among people diagnosed
with Schizoid PD. First, we tested 2 hypotheses:
(1) the pattern of cognitive abilities in Schizoid PD
patients with BIF (BIF+) deviates significantly
from that in Schizoid PD patients without BIF
(BIF-);
(2) whether the proportions of performance deficits
on the VIQ and the VC in BIF+ differ significantly
from that in BIF-, verbal reasoning may be
considered a more specific weakness of BIF
condition. Conversely, whether the proportions of
performance deficits on the VIQ and the VC in
BIF+ do not differ significantly from that of BIF-,
these two indexes may not have the highest
discriminating value for the presence of BIF in
people diagnosed with schizoid personality
disorder.
Second, we examined the relationships between
clinic, demographic, and cognitive characteristics in
BIF+ and BIF-. Additionally, we sought to identify
predictors associated with substance use (SU)
behavior in participants with Schizoid PD.
2. MATERIALS AND METHODS
2.1. Participants
The present retrospective study included blind data
collected between September 2012 - October 2020
from patients referred to the Clinical Section of
Psychiatry participants within the Department of Head-
Neck Care Unit of Psychiatry and Psychology Federico
216 Journal of Intellectual Disabi lity - Diagnosis and Treatment, 2023, Vol. 1 1, No. 5 Galletta et al.
II University Hospital Naples (Campania, Italy). The
psychiatrist codified for each patient the presence or
the absence of Axis II personality disorder using the
Italian version of the Structured Clinical Interview for
DSM-IV Axis II Personality Disorders (SCID-II; First et
al., 1997) [55], Axis I disorder using the Structured
Clinical Interview for DSM-IV-TR Axis I Disorders
Clinician Version [56] (SCID-CV), and substance use
behavior using the Substance Use Module E of the
SCID-I. The major inclusion criterion was Schizoid
Personality Disorder (Schizoid PD) based on the DSM-
IV-TR [1] and recorded in the system of the electronic
patient file. Exclusion criteria were the presence of 1)
IQ below 71; 2) neurological diseases and motor
impairments; 3) head injury; 4) diagnosis of mental
disorder other than Schizoid PD. A sample of 47
participants with an average age of 35 years was thus
developed.
2.2. Procedure
In the Psychodiagnostics and Neuropsychology
Participant Clinic of the Department mentioned above,
the following variables were recorded: DSM-IV-TR axis
II diagnosis, age, gender, level of education, marital
status, pharmacological therapy, substance use, and
neuropsychological data. After anonymous data
processing was guaranteed, informed consent for
collecting data from the electronic patient file was
obtained from each patient. As a retrospective study,
the approval by an ethics committee was not
applicable, but the protocol was submitted and
approved by the research office of the Ethical
Committee of the University of Naples Federico II (part
of the Division of Legal Medicine of the Department of
Advanced Biomedical Sciences). Institutional Review
Board (IRB) was obtained per institutional guidelines.
All procedures performed in this study were in
accordance with The Code of Ethics of the World
Medical Association (Declaration of Helsinki) for
medical research involving humans.
2.3. Neuropsychological Assessment
The participants' intellectual functioning was
assessed by using the Italian version of the Wechsler
Adult Intelligence Scale-Revised [54] (WAIS-R). The
WAIS-R consists of eleven subtests yielding raw
scores, then converted to age-corrected scaled scores
[57]. The full-scale intelligence quotient (FSIQ) is a
measure of the individual's general cognitive ability
obtained by summing all subtests' scaled scores and
then converting them to age-corrected standard scores.
The verbal intelligence quotient (VIQ) is a measure of
acquired knowledge, verbal reasoning, short-term
memory, and mathematical skills calculated by
summing the Information, Comprehension, Arithmetic
Reasoning, Digit Span, Similarity, and Vocabulary
subtest scaled scores. The performance intelligence
quotient (PIQ) is a measure of perceptual reasoning,
visuospatial abilities, and processing speed derived
from the sum of Picture Completion, Picture
Arrangement, Block Design, Object Assembly, and
Digit Symbol-Coding subtest scaled scores (for an
exhaustive description of the WAIS-R [53].
2.4. Statistical Analysis
According to the DSM-IV-TR criteria (APA, 2000),
patients split into two groups: the Schizoid PD with BIF
group (BIF+: 71 ≤ IQ ≤ 84) and the Schizoid PD without
BIF group (BIF-: IQ ≥ 85). Descriptive statistics of
clinical and demographic variables are presented in
Table 1 as means, standard deviations, and
frequencies. Shapiro–Wilk test was used to check for
normality of data distribution, and homogeneity of
variance was estimated using Levene’s test. Non-
parametric analyses were used when the assumptions
of homogeneity of variance or normality were violated
(p< 0.05). A first analysis was carried out to assess the
clinical and demographic characteristics of the two
groups. Continuous variables were compared between
groups using the Student’s t-test or Mann–Whitney U
test, as appropriate. Comparisons of categorical
variables were performed using Fisher's exact test or
Pearson's Chi-square test, and p-values less than 0.05
were considered significant. Neuropsychological
measures (WAIS-R IQ, three-factor index, eleven
subtest scores) were compared between groups using
t-tests or U-tests, and effect sizes (Cohen's d) were
calculated. Frequency analyses on the proportions of
performance deficits reported by the two groups were
performed, and the effect sizes (Cramer's V) were
calculated. Pearson or Spearman's correlation was
used to check relationships between clinical,
demographic, and cognitive features of Schizoid PD
patients. Binary logistic regressions were carried out
using the forward selection (Likelihood Ratio) method
based on the Wald test statistics with substance use
(SU) as the bimodal outcome (SU- = absent; SU+ =
present) and as predictors the demographic and clinical
variables in the regression modela, the cognitive
measures as the WAIS-R three factor indexes’ z-
scores in the regression modelb, and the eleven
subtests’ z-scores in the regression modelc, to
determine whether cognitive skills account for
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 217
substance use, and to quantify (OR = odds ratio) to
which extent this is so. Statistical analyses were
performed using IBM SPSS Statistics software (version
21.0), adopting an alpha error rate of 0.05 (two-tailed)
and a conservative statistical power of 95%.
3. RESULTS
3.1. Clinical and Demographic Characteristics
The study sample consisted of 47 Italian Schizoid
PD patients (89% males; mean age 27.64 ± 8.32
years); 31 of them had attained the 12th grade of
education (High school diploma), 8 completed the 8th
grade (Middle school), and 8 had a University degree.
Many Schizoid PD patients were single (81%), and all
of them were compliant with the prescribed
pharmacological therapy. The majority (91%) were
receiving atypical antipsychotics and 9% SSRI drugs.
Substance use was reported by 49% of Schizoid PD
patients; of them, 79% were cannabis and tobacco
smokers, and 21% were alcohol drinkers and tobacco
smokers.
3.2. Comparisons of Demographic and Clinical
Variables
According to the WAIS-R full-scale intelligence
quotient score (i.e., FSIQ), the sample of 47 Schizoid
PD patients was divided into two groups (mean total
FSIQ = 91.83; SD = 14.56). The Schizoid PD with BIF
group included 24 patients who scored from 71 to 84
(mean FSIQ = 79.92; SD = 4.49). In the Schizoid PD
without BIF group, there were 23 patients with FSIQ
scores higher than 84 (mean FSIQ = 104.26; SD =
10.30). A descriptive summary of the other
demographic characteristics of the two groups appears
in Table 1. Data were not normally distributed
(Shapiro–Wilk test, p< 0.05), and between-group
variances were unequal (Levene's test, p< 0.05).
Therefore, non-parametric analyses were performed.
Statistical comparisons between the two Schizoid PD
patient groups were run using the Mann-Whitney U-test
for independent groups. No statistically significant
differences were found among BIF+ and BIF- in age
and years of education. The frequency analysis results
showed no differences between the two groups in
terms of demographic (i.e., gender, marital status) and
clinical (i.e., pharmacological treatment) characteristics.
3.3. Comparisons of Neuropsychological Variables
Results obtained with the neuropsychological
assessment groups-averaged WAIS-R IQ, three-factor
index, and eleven subtest scores appear in Table 2.
Comparisons between groups of cognitive measures
were performed to test the hypothesis (1). The results
of the statistical analysis using the Mann-Whitney U-
test for independent groups and Cohen's effect sizes
are listed in Table 2. There were significant differences
between the scores of the two groups on all verbal
subtests, such as the Information, Vocabulary,
Comprehension, Similarities, Digit Span, and Arithmetic
Reasoning. BIF+ performed significantly worse than
BIF- on subtests such as Picture Arrangement, Digit
Table 1: Descriptive Statistics of Demographic and Clinical Variables of Schizoid PD Patients with and without BIF
Schizoid PD
with BIF
(n = 24)
Schizoid PD
without BIF
(n = 23)
Test statistic
M ± SD
M ± SD
U
p-value
Age (years)
25.83 ± 6.91
29.52 ± 9.35
217.50
0.217
Education (years)
12.17 ± 2.82
13.78 ± 2.79
199.00
0.103
Frequencies (%)
Frequencies (%)
χ2
p-value
Gender
Males/Females
21/3 (87%)
21/2 (91%)
0.18
0.672
Marital stat us
Engaged/Single
3/21 (12%)
6/17 (26%)
1.40
0.237
Pharmacological treatment
SSRI
2/22 (8%)
2/21 (9%)
0.00
0.965
Atypical antipsychotics
22/2 (92%)
21/2 (91%)
0.00
0.965
Note: U= Mann-Whitney U-test for independent groups on years of age and education of the two grou ps: Schizoid PD w ith BIF (n=24) a nd BPD without BIF (n = 23);
χ2 = frequency analys is (Pearson’s Chi-square test) on gender, marital status, and pharmacological treatment ( SSRI, Atypic al anti psyc hotics ) data of the two groups ;
p-value was significant at .05 level.
218 Journal of Intellectual Disabi lity - Diagnosis and Treatment, 2023, Vol. 1 1, No. 5 Galletta et al.
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 219
Figure 1: Frequency analysis of WAIS-Rperformance deficits (scores that were more than one standard deviation below the
normative mean, i.e., ≤ 6) observed inSchizoid PD patients with BIF (BIF+: n = 24; black bars) and in Schizoid PD patients
without BIF (BIF-: n = 23; white bars). A) Verbal comprehension index; B) Perceptual organization index C) Freedo m from
distractibility index. The results of χ2 are listed in Table 2, and the p-value was significant at 0.05 level.
Note: IN= Information; VO= Vocabulary; CO= Comprehension; SI= Similarities; BD= Block Design; PA= Picture Arrangement;
PC= Picture Completion; OA= Object Assembly; AR= Arithmetic Reasoning; DSC= Digit Symbol-Coding; DSP= Digit Span.
* p < 0.05.
** p < 0.01.
Symbol-Coding, Object Assembly, and Block Design.
There was no statistically significant difference
between the two groups' performances on the Picture
Completion subtest. Thereby, statistically significant
between-group differences were found in the verbal IQ
(d = 0.70), the performance IQ (d = 0.43), the verbal
comprehension index (d = 0.54), the freedom from
distractibility index (d = 0.46), and the perceptual
organization index (d = 0.27) scores.
3.4. Comparisons of Performance Deficits
On a standardized assessment, a cognitive
processing deficit is defined by a score that is more
than one standard deviation below the population
mean. Comparisons between the two groups’
proportions of performance deficits on the WAIS-R IQs
(mean = 100; SD = 15; deficit scores = ≤ 84), three-
factor indexes, and the eleven-subtests (mean = 10;
SD = 3; deficit score = ≤ 6) [53,57-59] were performed
with Pearson's Chi-square analysis to test the
hypothesis (2). Results of frequency analysis and
significant Cramer's V effect sizes are listed in Table 2.
There was a significant between-groups difference in
the proportions of the Vocabulary subtest's
performance deficits, as 42% of BIF+ compared to 9%
of BIF- reported deficit scores on this subtest. No BIF-
obtained deficit scores on the Comprehension and Digit
span subtests compared to 21% and 25% of BIF+,
respectively. Statistically significant differences
between the proportions of performance deficits were
observed in the Picture Arrangement (46% of BIF+
than 9% of BIF-), the Arithmetic Reasoning (42% than
4%), and the Similarities (33% than 4%) subtests.
There were no significant differences with respect to
deficit scores of the two groups on the Information,
Block Design, Picture Completion, Object Assembly,
and Digit Symbol-Coding subtests (see Figure 1).
While no BIF- reported poor verbal IQ, verbal
comprehension, and freedom from distractibility index
scores, the majority of BIF+ (54%) obtained a verbal IQ
score lower than one standard deviation below the
normative mean, the 33% of them reported poor verbal
comprehension index scores, and the 29% of patients
obtained poor freedom from distractibility index scores.
There was no statistically significant difference
between the two groups’ proportion of performance
deficits on the perceptual organization index.
3.5. Relationships between Clinical Demographic
and Cognitive Variables
Spearman’s correlation coefficient analysis revealed
the age of BIF+ was significantly associated with
gender (r = 0.50; p = 0.01) since females were older
compared to male patients in this group and with years
of education (r = 0.66; p< 0.001). There was a negative
association between the age of BIF+ and the
perceptual organization index (r = -0.48; p = 0.01),
especially with scores on the Picture Completion (r = -
220 Journal of Intellectual Disabi lity - Diagnosis and Treatment, 2023, Vol. 1 1, No. 5 Galletta et al.
0.46; p = 0.02) and the Block Design (r = -0.45; p =
0.03) subtests. Gender of BIF+ was significantly
associated with scores on the Vocabulary subtest (r =
0.44; p = 0.03) and the perceptual organization index (r
= -0.51; p = 0.01), in particular with scores on the Block
Design subtest (r = -0.57; p = 0.003). BIF+ female
patients performed better on the Vocabulary subtest
and worse on the Block Design subtest compared to
BIF+ male patients. The full-scale IQ scores of BIF+
were slightly more associated with the verbal
comprehension index (r = 0.66; p< 0.001) compared to
the perceptual organization index (r = 0.41; p = 0.04).
There were no statistically significant associations
between pharmacological therapy, marital status, and
the other variables in the BIF+. The age of BIF- was
significantly associated with years of education (r =
0.54; p = 0.01) and with the freedom of distractibility
index (r = 0.42; p = 0.04), especially with the Digit span
subtest scores (r = 0.48; p = 0.02). The full-scale IQ
scores of BIF- were slightly more associated with
verbal comprehension (r = 0.73; p< 0.001) compared to
the perceptual organization (r = 0.62; p = 0.002), and
the freedom from distractibility (r = 0.45; p = 0.03)
indexes. There were no statistically significant
associations between gender, marital status,
pharmacological therapy, and other variables in the
BIF-. Significant correlations were found between the
global cognitive capacity (FSIQ) of the total Schizoid
PD sample and years of education (r = 0.30; p = 0.04),
the verbal comprehension (r = 0.87; p< 0.001), the
freedom from distractibility (r = 0.75; p< 0.001), and the
perceptual organization (r = 0.66; p< 0.001) indexes.
The full-scale IQ scores of the total sample were more
associated with verbal IQ (r = 0.94; p < 0.001) than with
the performance IQ (r = 0.79; p< 0.001) scores. There
were no statistically significant associations between
age, gender, marital status, pharmacological therapy
variables, and FSIQ scores of the total Schizoid PD
sample.
3.6. Logistic Regression Models for Substance Use
Behavior
Forward binary logistic regression analysis with
substance use behavior (SU) as an outcome and the
demographic (i.e., age, gender, education, marital
status) and clinical (i.e., pharmacological therapy,
borderline intellectual functioning) as predictors
variables revealed that only BIF condition accounted
for the presence of substance use behavior (SU+ vs.
SU-) in the total sample of Schizoid PD patients (see
Table 3). The Wald criterion (testing the null hypothesis
that the risk of SU associated with the predictor
variable is unity) demonstrated that borderline
intellectual functioning made significant contributions
(Wald χ2
[1] = 8.709, p = 0.003) to the prediction of
substance use behavior, providing an odds ratio (OR) –
(Exp[betas]) of 6.9 for SU+ than SU- categorization
(OR higher than 1 indicate a risk factor for SU+). This
result means that BIF+ were about 6 times more likely
substance users than not. The regression modela
explained the 72% variation in the outcome, correctly
classifying up to 74% of SU+ and 71% of SU-. Results
of forward binary logistic regression analyses with
cognitive variables (i.e., the WAIS-R three factor
indexes' z-scores = modelb; the eleven subtests’ z-
scores = modelc) as predictors, and substance use as
outcome showed that the verbal comprehension index
z-scores reliably discriminated between
absence/presence of substance use in Schizoid PD
patients (Wald χ2
[1] = 8.619, p = 0.003; OR=0.21), as
well as the Vocabulary subtest performances were
negatively related to the outcome (Wald χ2
[1] = 9.364, p
= 0.002; OR=0.28). These results would mean that for
each one-unit increase in the standard deviation of the
verbal comprehension index and in the Vocabulary
subtest scores, the likelihood of being a substance user
may decrease by about 79% and 72%, respectively
(OR lower than 1 indicate a protective factor for SU+).
Table 3: Statistics for Logistic Forward Regression Models with Substance Use as the Criterion Variable
95%Clfor Exp(B)
Variable in the equation
B*
p-value
Exp(B)†
Lower bound
Upper Bound
Clinical variable
Borderline intellectual functioning
1.929
0.003
6.881
1.911
24.773
Cognitive variables
Verbal comprehension
- 1.568
0.003
0.209
0.073
0.594
Vocabulary
- 1.260
0.002
0.284
0.127
0.636
Note: Forward binary logistic regression models with substance use as the outcome (SU- vs. SU+) in the Schizoid PD patients sample (n = 47). Predictors not
eligible to enter into the equation were demographic (age, gender, e ducation, marital s tatus) and clinical (pharmacological t herapy) variables for regression modela,
WAIS-R three-factor indexes (verbal comprehension, perceptual organization, freedom from distr actibilit y) z-scores for re gression modelb; W AIS-R 11 subtests’ z-
scores for regression modelc.
*B= regress ion coeff icient; p-value= significant at .05 level; † Exp(b)= odds ratio; 95%Cl = 95% confidence interval.
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 221
The regression modelb explained 77% of the variation
in the outcome, correctly classifying up to 78% of SU+
and 75% of SU- cases, compared to 70% of the
variation in the substance use behavior explained by
the regression modelc that is correctly classifying up to
70% of SU+ and 71% of SU- cases.
4. DISCUSSION
The principal aim of this study was to investigate the
clinical, demographic, and cognitive profile of patients
with schizoid personality disorder and borderline
intellectual functioning (BIF+) assessed in our daily
outpatient psychiatry practice. While BIF+ have shown
a pattern of cognitive abilities that deviated significantly
from that observed for BIF-, there were no between-
group differences on clinical and demographic profiles.
The neuropsychological assessment revealed BIF+
compared to BIF- performed worse on all WAIS-R
cognitive tasks other than the Picture Completion
subtest. In line with other studies, Schizoid PD patients
might have a low reality contact and poor awareness of
environmental details, and they may be less able to
understand part-whole visuospatial relationships
needed for visual object perception [44]. This finding
would seem to suggest that the Picture Completion
subtest is not useful for discriminating the presence of
BIF in Schizoid PD. Furthermore, there was no
significant difference between the two groups'
proportions of deficit scores on the perceptual
organization index. This WAIS factor index provides an
estimate of abstract fluid reasoning, integration of
visual perceptual stimuli with relevant motor responses,
ability to solve unfamiliar problems, and planning and
interpreting social events [59]. Of all subtests, including
the perceptual organization index, BIF+ reported
significantly more performance deficits only on the
Picture Arrangement subtest compared to BIF-. As has
been previously reported in the literature, the WAIS
Picture Arrangement reveals information about an
individual's ability to grasp the essential messages in
social interaction, comprehension of irony, and capacity
to anticipate consequences of someone's actions
[60,61]. Patients with schizoid personality disorder
reportedly do not desire relationships due to deficits in
their capacity to relate meaningfully with others,
difficulties understanding social interaction, and an
unintentional tendency to disregard social conventions
[62,15]. A number of authors have recognized that
dysfunctions in mentalizing abilities connected with
executive functions may explain destructive social
interactions among persons with borderline intellectual
functioning [47,63,64]. According to Hengartner et al.
[52] many Schizoid PD patients included in the present
study reported slow information processing speed (i.e.,
low scores on the WAIS Digit Symbol-Coding),
associated with fluid intelligence that is highly relevant
for social functioning and psychosocial adaptation
[65,66]. The cognitive profile of BIF+ is worth
discussing. Besides the severe impact on social and
adaptive abilities, these patients have reported
difficulties in verbal and perceptual abstract reasoning,
as well as slower processing speed and impaired
working memory. The difficulty with abstract material in
BIFs has been associated with limited capacity to hold
and manipulate information in mind (i.e., poor working
memory), and this might explain their low concept
formation, difficult understanding of the meaning of
many words, and poor motivation to learn [67-69]. BIFs
may have less efficient cognitive abilities to constantly
update personal knowledge with new information, to
learn by experience, and to master real-life situations
adaptively [70,53]. Further, the findings that BIF+
compared to BIF- have reported poorest performances
on tasks that require verbal understanding,
mathematical skills, and the ability to remember
instructions manipulating information in short-term
memory (i.e., lower scores on the WAIS Arithmetic
Reasoning and Digit Span) would support the notion
that working memory impairment is closely related to
deficit performance on arithmetic word problems, and
might represent a high-risk factor for educational
underachievement (Swanson and Sachse-Lee, 2001;
Gathercole et al. 2006; Alloway, 2010) [42,71,72]. In
line with the results of our previous study [53], BIF+
compared to BIF- reported more frequently impaired
performances on the WAIS Vocabulary, Similarities,
and Comprehension. Moreover, in the present study,
the effect sizes indicate primarily deficits in the verbal
IQ and verbal comprehension (VC) domain in BIF+
than BIF- suggesting specific weaknesses related to
verbal reasoning underlying the BIF condition. We can
assume the WAIS verbal IQ and VC may be the most
useful indexes discriminating the presence of BIF in
people diagnosed with schizoid personality disorder.
Consistent with the correlational findings, in the BIF+
group, males compared to females reported lower
scores on the verbal subtest Vocabulary, while females
performed worse than males on the performance
subtest Block Design. The present results can be
interpreted as poorer logical reasoning to solve
unfamiliar problems than acquired knowledge and the
ability to express thoughts verbally for BIF+ females
compared to males. Conversely, BIF+ males could
have more difficulty, as compared to females, in
expressing thoughts verbally and/or have poor
222 Journal of Intellectual Disabi lity - Diagnosis and Treatment, 2023, Vol. 1 1, No. 5 Galletta et al.
acquired knowledge to face everyday situations than
logical problem-solving ability. However, there is still an
ongoing debate in the literature on gender differences
in verbal and spatial abilities, as well as crystallized
and fluid intelligence in normally developing individuals
[73-77]. Since these relationships were not found for
BIF-, further studies are needed to evaluate the
relevance of cognitive gender differences for borderline
intellectual functioning in schizoid personality disorder
condition. In the present study, the global cognitive
abilities (i.e., the WAIS FSIQ scores) of Schizoid PD
patients were strongly associated with the capacity of
acquisition, organization, and retrieval of knowledge
(i.e., the WAIS VIQ), as well as positive related to the
level of educational attainment. One can argue that
individuals with higher cognitive abilities could have
more cognitive resources available to acquire
knowledge and achieve academic success. The 49% of
Schizoid PD patients included in the current study
reported substance use. The regression analysis
finding that BIF+ were 7 times more likely to be
substance users than not is in line with studies that
have identified a relationship between increased
substance use and frequency of PD in individuals with
BIF [12, 78, 79]. Further, Schizoid PD patients were
more able to learn and generalize verbal information to
solve novel problems (i.e., higher verbal
comprehension index scores) and express thoughts
verbally (i.e., better performances on the WAIS
Vocabulary) and were less likely to be substance
users. Although the Vocabulary subtest score is the
best indicator of general intelligence and an individual's
intellectual potential, often used to estimate the
premorbid level of functioning [80] the performance is
susceptible to improvement by experience or schooling
[81]. Probably, adequate cognitive resources, a wealthy
educational background, and normal language
development may be protective factors for substance
use. This interpretation is in accord with previous
population-based and longitudinal studies that
investigated cognitive functioning in childhood,
academic achievement, and substance use in
adulthood. Researchers found that poorer verbal
reasoning abilities and decreased ability to express
thoughts verbally accounted for by parental and low
basic education, were associated with lower academic
attainment and lifetime substance use [82,83]. Several
interpretations can be made from our findings. First,
weakened verbal abstract reasoning and reduced
working memory may exert a negative influence on
mastering other basic abilities such as reading, writing,
and mental arithmetic calculating required to achieve
personal independence. In the case of an educational
environment that fails to provide adequate stimuli,
individuals with these difficulties might be less
motivated to learn, avoiding mental training with
abstract materials [69,84]. As a result, these individuals
may face long-term learning difficulties, experiencing
constant situations of failure and academic
underachievement. Moreover, feelings of
incompetence due to not being able to reach age-
appropriate expectations (especially in BIFs) may
increase the withdrawal from life experiences and
social interactions, hindering the development of useful
coping strategies to deal with stressful events, likewise,
social competency to establish interpersonal relations
(characteristics of schizoid traits). When individual
features interfere extremely with the ability to form
relationships, control impulses or emotions, perceive
oneself and others accurately, and enjoy life or function
at work, personality is defined as pathological [81].
Nevertheless, this study is a reflection of actual daily
clinical practice, and several limitations need to be
addressed. First, the participants were assessed using
the DSM-IV rather than DSM-5 [15] and were
administered the WAIS-R rather than the WAIS-IV [85];
still, the last was not standardized in the Italian
population when neuropsychological data were
collected (i.e., from September 2012). Further
limitations are the reduced sample size for detecting
smaller effects and the lack of information related to
perceived social support, occupation, and married
status satisfaction, which are useful to investigate the
quality of participants' lives. Taken together, the main
results of the present retrospective study suggest the
need for neuropsychological evaluation in patients with
schizoid personality disorder to identify weakened
cognitive skills important to plan targeted strategies
able to prevent negative outcomes. Early identification
of borderline intellectual functioning and specialized
treatments improving verbal reasoning abilities,
possibly incorporating family or community
interventions, may support these individuals to resume
a healthier trajectory and attain social and vocational
functioning.
CONCLUSIONS
• BIF in Schizoid PD participants is correlated with
a peculiar cognitive pattern of verbal, perceptual,
attention, memory, planning, and problem-
solving dysfunctions
• The verbal IQ and the Verbal Comprehension
Index (VC) discriminated the presence of BIF in
Schizoid PD participants
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 223
• The BIF condition and the VC index were the
predictors most associated with substance use
behavior in people diagnosed with schizoid
personality disorder
DECLARATIONS OF INTEREST
None.
FUNDING
This research did not receive any specific grant
from funding agencies in the public, commercial, or not-
for-profit sectors.
REFERENCES
[1] APA, American Psychiatric Association. Diagnostic and
statistical manual of mental disorders. 4rd ed. Washington
DC: American Psychiatric Association 2000.
[2] Martín ez-Leal R, Folch A, Munir K, et al. The Girona
Declaration on borderline intellectual functioning. Lancet
Psychiat 2020; 7.
https://doi.org/ 10.1016/S2215-0366(20)30001 -8
[3] Salvador-Carulla L, García-Gutiérrez JC, Gutiérrez-Colosía
MR, et al. (Borderline intellectual functioning: consensus and
good practice guidelines. Rev Psiquiatr Salud Ment (Barc.)
2013; (6): 109-120.
https://doi.org/ 10.1016/j.rps men.2012.12.002
[4] Wieland J, Van Den Brink A, Zitman, FG. The prevalence of
personality disorders in psychiatric outpatients with
borderline intellectu al functioning: Comparison with
outpatients from regular mental health c are and out patients
with mild intellectual disabilities. Nord J Psychiatry 2015;
(69): 599-604. Available fr om:
http://hdl.hand le.net/ 1887/38454
[5] Venkatesan S. Demographic, Cognitive and Psycho-Social
Profile of Adults with Borderline Intellectual Functioning. J
Contemp Psychol Res 2017; (4): 1-13.
[6] Fernell, E, Ek U. Borderline intellectual functioning in children
and adoles cents–insufficiently recognized difficulties. Acta
Paediatrica 2010; (99): 748-753.
https://doi.org/ 10.1111/j.1651-2227.2010.01707
[7] Emerson E, Einfeld S, Stancliffe RJ. The mental health of
young children with intellectual disabilities or borderline
intellect ual functioning. Soc Psych Psych Epid 2009; (45):
579-587.
https://doi.org/ 10.1007/s001 27-009-0100-y
[8] Gigi K, Werbeloff N, Goldberg S, et al. Borderline intellectual
functioning is associated with poor social functioning,
increase d rates of psychiatric diagnosis, and drug use–A
cross-sectional population-based study. Eur
Neuropsychopharm 2014; (24): 1793-1797.
https://doi.org/ 10.1016/j.euro neuro.2014.07.016
[9] Hayes S, Shackell P, Mottram P, et al. The prevalence of
intellect ual disability in a major U K prison. Brit J Learn Disabil
2007; (35): 162-167.
https://doi.org/ 10.1111/j.1468-3156.2007.00461.x
[10] Herrington V. Assessing the prevalence of intellectual
disability among young male prisoners. J Intellect Disabil Res
2009; (53): 397-410.
https://doi.org/ 10.1111/j.1365-2788.2008.01150.x
[11] Luteijn I, D idden R, Van der Nagel J. Individuals with mild
intellect ual disability or borderline intellectual functionin g i n a
forensic addiction treatment center: Prevalence and clinical
characteristics. Adv Neurodev Disord 2017; (1): 240-251.
https://doi.org/ 10.1007/s412 52-017-0031- 7
[12] Didden R, VanDerNagel J, Delforterie M, et al. Substance
use disor ders in people wi th intellectu al disability. Curr Opin
Psychiatr 2020; (33): 124-129.
https://doi.org/ 10.1097/YCO. 0000000000000569
[13] Moran P , Klinteberg B A, Batty GD, et al. Brief report:
childhood intelligence predicts hospitalization with personality
disorder in adulthood: evidence from a population-based
study in Sweden. J Pers Disord 2009; (23): 535-540.
https://doi.org/ 10.1521/pedi.2009.23.5.535
[14] Gale CR, Batty GD, Tynelius P, et al. Intelligence in early
adulthood and subsequent hospitalis ation and admission
rates for the whole range of mental disorders: a longitudinal
study of 1,049,663 men. Epidemiology 2010; (21): 70-77.
https://doi.org/ 10.1097/EDE.0b013e3181c17da8
[15] APA, American Psychiatric Association. Diagnostic and
statistical manual of mental disorders. 5rd ed. Washington,
DC: American Psychiatric Association 2013.
[16] Martens WH, Palermo GB. L oneliness and associate d violent
antisoci al behavior : analysis of the case rep orts of Jeffrey
Dahmer and Dennis Nilsen. Int J Offender Ther 2005; (49):
298-307.
https://doi.org/ 10.1177/0306624X05274898
[17] Mulay AL, Thurnauer H, Cai n N M. Schizoid personality
disorder. Zeigler -Hill V, Shackelford TK, E ncyclopedia of
personality and individual differences, Springer International
Publishing 2017; 1-9.
https://doi.org/ 10.1007/978-3-319-28099-8_626-1
[18] Levi-Belz Y, Gvion Y, Levi U, et al. Beyond the mental pain:
A case-control study on the contribution of schizoid
personality disorder sym ptoms to medically serious suicide
attempts. Compr Psychiat 2019; (90): 102-109.
https://doi.org/ 10.1016/j.comppsych.2019.02.005
[19] Nirestean A, Lukacs E, Cimpan D, et al. Schizoid personality
disorder—the peculiarities of their interpersonal relationships
and exist ential roles. Perso nal Me nt Health 2012; (6): 69-74.
https://doi.org/ 10.1002/pmh. 1182
[20] Thomat AL. Pathways between Trauma, Schiz oid Personality
Traits, and Substance Pro blems Among Males on P robation
(Doctoral dissertation, UC Santa Barbara). Ca lifornia Digital
Library 2014. Available from:
https://escholarship.org/uc/ item/2 p56900h
[21] Loza W, Hanna S. Is schiz oid personality a forerunner of
homicidal or suicidal behav ior? A case study. Int J Offender
Ther 2006; (50): 338-343.
https://doi.org/ 10.1177/0306624X05285093
[22] Koch J, Berner W, Hill A, et al. Sociodemographic and
diagnostic characteristics of homicidal and nonhomici dal
sexual offenders. J Forensic Sci 2011; (56): 1626-1631.
https://doi.org/ 10.1111/j.1556-4029.2011.01933.x
[23] Apostolopoulos A, Michopoulos I, Zachos I. et al. Association
of Schizoid and Schizotypal Personality disorder with violent
crimes and homicides in Greek prisons. Ann G enn Psychiatry
2018; (17): 1-9.
https://doi.org/ 10.1186/s129 91-018-0204- 4
[24] Kosson DS, Blackburn R, Byrnes KA, et al. Assessing inter-
personal aspec ts of schizoid personali ty disorder: Preliminary
validation studies. J Pers Assess 2008; (90): 185-196.
https://doi.org/ 10.1080/0022389070 1845427
[25] Fenning RM, Baker JK, Baker BL, et al. Parent-child
interaction over time in families of young children with
borderline intellectual functioning. J Fam Psychol 2014; (2 8):
326-335.
https://doi.org/ 10.1037/a0036537
[26] Cohen P, Brown J, Smaile E. Child abuse and neglect and
the development of mental disorders in the general
population. Dev Psychopathol 2002; (13): 981-999.
https://doi.org/ 10.1017/S0954579401004126
[27] Jenkins JVM, Woolley DP, Hooper SR, et al. Direct and
indirect effects of brain volume, socioeconomic status, and
224 Journal of Intellectual Disabi lity - Diagnosis and Treatment, 2023, Vol. 1 1, No. 5 Galletta et al.
family stress on child IQ. J Child Adolesc Behav 2013; (1):
1-12.
https://doi.org/ 10.4172/2375-4494.1000107
[28] Ninivaggi FJ. Borderline intellectual functioning and
academic pr oblems. In: S adock BJ, Sadock VA, Ruiz P,
Kaplan & Sadock’s 2009. Available from:
https://scholar.google.com/scholar_lookup ?title=Border line%
20intellectual%20functioning %20and%20academic %20probl
ems&author=F.J.%20Ninivagg i&publication_year=2009
[29] Thylstrup B, Hesse M. “I am not Complaining”—Ambivalence
Construct in Schizoid Personality Disorder. Am J Psychol
2009; (63): 147-167.
https://doi.org/ 10.1176/appi.psychotherapy.2009.63.2.147
[30] Masi G, Marches chi M, Pfanner P. Adolescents with
borderline intellectual functi oning: Psychop atholog ical risk.
Adolescence 1998; (33): 415-424.
[31] Bradley RH, Corwyn RF. Socioeconomic status and child
development. Ann Rev Psychol 2002; (53): 371-399.
https://doi.org/ 10.1146/annurev.psych.53. 10090 1.13523 3
[32] Farrington DP, Gelder MG, Lopez-Ibor JJ, Andreasen N.
Psychosocial causes of offending. In New Oxford Textbook
of Psychiatry. Oxford University Press 2000; 20 29-36.
[33] Hassiotis A, Strydom A, Hall I, et al. Psychiatric morbidity and
social functioning among adults with borderline intelligence
living i n priv ate households. J Intellect Disabil Res 2007;
(52): 95-106.
https://doi.org/ 10.1111/j.1365-2788.2007.01001.x
[34] Pessoa L. On the relationship between emotion and
cognition. Nat Rev Neurosci 2008; (9): 148-158.
[35] Schulkin J, Thompson BL, Rosen JB. Demythologizing the
emotions : a daptation, cogni tion, and visceral representations
of emotion in the nervous sys tem. Brain Cognition 2003;
(52): 15-23.
https://doi.org/ 10.1016/S0278-2626(03)00004 -6
[36] Inzlicht M, Bartholow BD, Hirsh JB. Emotional foundations of
cognitive control. Trends Cogn Sci 2015; (19): 126-132.
https://doi.org/ 10.1016/j.tics.2015.01.004
[37] Bogg T, Finn PR. A self‐regulatory model of behavioral
disinhibi tion in late adolescence: Integrating personality
traits, externalizing psychopathology, and cognitive capacity.
J Pers 2010; (78): 441-470.
https://doi.org/ 10.1111/j.1467-6494.2010.00622.x
[38] Neely-Prado A, Navarrete G, Huepe D. Socio-affective and
cognitive predictors of social adaptation in vulnerable
contexts. PloS One 2019; 14.
https://doi.org/ 10.1371/journal.pone.0218236
[39] Koenen KC, Moffitt TE, Roberts AL, et al. Childhood IQ and
adult mental disorders: a test of the cognitive reserve
hypothesis. Am J Psychiat 2009; (166): 50-57.
https://doi.org/10.1176/appi.ajp.2008.08030343
[40] Bonifacci P, Snowling MJ. Speed of processing and reading
disability: A cross-linguistic investigation of dysl exia and
borderline intellectual functioning. Cognition 2008; (107):
999-1017.
https://doi.org/ 10.1016/j.cognition.2007.12.006
[41] Alesi M, Rappo G, Pepi A. Emotional profile and intellectual
functioning: a comparison among children with b orderline
intellect ual functioning, average intellectual functioning , and
gifted intellectual functioning. SAGE Open 2015.
https://doi.org/ 10.1177/2158244015 589995
[42] Alloway TP. Working memory and executive function profiles
of individuals with borderline intellect ual function ing. JIDR
2010; (54): 448-456.
https://doi.org/ 10.1111/j.1365-2788.2010.01281.x
[43] Karande S, Kanchan S, Kulkarni M. Clinical and
psychoeducational profile of children with borderline
intellect ual functioning. The Indian Journal of Pediatrics
2008; 75.
https://doi.org/ 10.1007/s120 98-008-0101-y
[44] Pluzhnikov IV, Kaleda VG. Neuropsychological findings in
personality disorders: AR Luria's Approach. Psychology in
Russia 2015; (8): 113-125.
https://doi.org/ 10.11621/pir.2015.0210
[45] Pulina F, Lanfranchi, S, Henry L, et al. Intellectual profile in
school-aged children with borderline intellectual function ing.
Res Dev Disabil 2019; 95.
https://doi.org/ 10.1016/j.ridd.2019.103498
[46] Cornoldi C, Giofre D, Orsini A, et al. Differences in the
intellect ual pr ofile of children with intellectual vs. learning
disability. Res Dev Disabil 2014; ( 35): 2224-2230.
https://doi.org/ 10.1016/j.ridd.2014.05.01 3
[47] Baglio G, Blasi V, Sangiuliano Intra F. et al. Social
competence in children with borderline intellectual
functioning: delayed development of theory of mind across all
complex ity levels. Front Psychol 2016; (7): 1-10.
https://doi.org/ 10.3389/fpsyg.2016. 01604
[48] Dodge KA. Social cognition and children's aggressive
behavior. Child Dev 1980; (5 1): 162-170.
https://doi.org/ 10.2307/1129603
[49] Van Nieuwenhuijzen M, Vriens A, Scheepmaker M, et al. The
development of a dia gnostic instrument to measure social
information processi ng in c hildren with mild to b orderline
intellect ual disabilities. Res Dev D isabil 2011; ( 32): 358-370.
https://doi.org/ 10.1016/j.ridd.2010.10.01 2
[50] Van Rest MM, Matthys W, Van Nieuw enhuijzen M, et al.
Social information processing skills link executive functions to
aggressi on in adolescents with mild to borderline intellectual
disability. Child Neuropsyc hol 201 9; (25): 573-598.
https://doi.org/ 10.1080/09297049.2018.1495186
[51] Korsakova NK, Pluzhnikov IV. Neiropsikhologi-
cheskiypodkhod k Izucheniyuprotsessovadaptatsii
[Neuropsychological approach to adaptive process]. In
Akhutina TV, Glozman ZhM, (Eds.), Conference: Heritage of
Luria A.R. in contemporary scientific and cultural-historical
context: To the 100 anniversary from birthday of Luria A.R.
Moscow : Faculty of Psychology of Lomo nosov Moscow State
University 2012: 70-92.
[52] Hengartner MP, Ajdacic-Gross V, Rodgers S, et al. Fluid
intellige nce and empathy in association with personality
disorder trait-scores: exploring the link. Eur Arch Psy Clin N
2013; (264): 441-448.
https://doi.org/ 10.1007/s004 06-013-0441- 0
[53] Galletta D, Califano AI, Fausta M, et al. Cognitiv e correlates
of borderline intellectual functioning in bor derline personality
disorder. J Psychiatr R es 2020; (13 0): 372-380. Available
from: https:// pubmed.nc bi.nlm.nih.gov/32882579/
[54] Wechsler D. Manuale della Scala d'Inte lligenza W echsler per
Adulti-Riveduta (WAIS-R). Adattamento Italiano a cura di C.
Laicardi e A. Orsini. Firenze, Italy: Organizzazi oni Speciali
1997.
[55] First MB, Gibbon MA, Spitzer RL, et al. Structured clinical
interview for DSM-IV II personality disor ders (SCID-II).
Washington DC: American Psychiatic Press 1997.
[56] First MB, Spitzer RL, Gibbon M, et al. Structured clinical
interview for DSM-IV-TR axis I disorders, clinician version
(SCID-CV). American Psychiatric Press 1996.
[57] Wechsler D, Padovani F, Orsini A, et al. WAIS-R: Wechsler
adult intelligence scale-revised: manuale. OS 2007.
[58] Parker K. Factor analysis of the WAIS-R at nine age levels
between 16 and 74 years. J Consult Clin Psych 1983; (51):
302-308.
https://doi.org/ 10.1037/0022-006X.51.2.302
[59] Padovani F. L’interpretazione psicologica della. WAIS-R.
Giunti OS 1999.
[60] Allison J, Blatt S, Zimet CN. The interpretation of
psychological tests. Hemisphere Publishing Corp/Harper &
Row Publishers 1968.
Cognitive Abilities in Schizoid Personality Disorder Journal of Intellectual Disability - Diagnosis and Treatment, 2023, Vol. 11, No. 5 225
[61] Baglio F, Cabinio M, Ricci C, et al. Abnormal development of
sensory-motor, visual temporal, and parahippocampal cortex
in chil dren with learning disabilities and borderline intellectual
functioning. Front Hum Neurosci 2014; (8): 1-11.
https://doi.org/ 10.3389/fnhum.2014.00806
[62] Smith A. Cognitive empathy and emotional empathy in
human behavior and evolution. T he Psychological Record
2017; (56): 3-21.
https://doi.org/ 10.1007/BF03395534
[63] Derks S, Van Wijngaarden S, Wouda M, et al. Effectiv eness
of the serious game ‘You & I’ in changing mentalizing abilities
of adults w ith mild to bor derline intellectual disabilit ies: a
parallel superiority randomiz ed control led trial. Trials 2019;
(20): 1-10.
https://doi.org/ 10.1186/s130 63-019-3608- 9
[64] Smirni D, Smirni P, Di Martino G, et al. Emotional awareness
and cognitive performance in borderline intellectual
functioning young adolescents. J NervMent Dis 2019; (207):
365-370.
https://doi.org/ 10.1097/nmd. 000000 0000000972
[65] Huepe D, Roca M, Salas N, et al. Fluid intelligence and
psychosocial outcome: from logical problem s olving to social
adaptation. PLo S One 2011; (6): 1-9.
https://doi.org/ 10.1371/journal.pone.0024858
[66] Nisbett RE, Aronson J, Blair C, et al. Intelligence: new
findings and theoretical developments. Am Psychol 2012;
(67): 130-159.
[67] Verguts T, De Boeck P. On the correlation between working
memory cap acity and performance on intelligence tests.
Learn Indivia D iffer 2002; (13): 3 7-55.
https://doi.org/ 10.1016/S1041-6080(02)00049 -3
[68] Engle RW, Kane MJ. Executive Attention, Working Memory
Capacity, and a Two-Factor Theory of Cognitive Control.
Psychol Learn Motiv 2004; (44): 145-199.
[69] Shaw SR. An educational pr ogramming framework for a
subset of students with diverse learning needs: Borderline
intellect ual functioning. Interv Sch Clin 2 008; (43): 291-299.
https://doi.org/ 10.1177/1053451208314735
[70] Devine RT, Hughes C. Relations between false belief
understanding and executive function in early childhood: A
meta-analysis. C hild Dev 2014; (85): 1777-1794.
https://doi.org/ 10.1111/cdev .12237
[71] Swanson HL, Sachse-Lee C. Mathe matical problem so lving
and working memory in children with learning disabil ities:
Both executive and phonological processes are important. J
Exp Child Psychol 2001; (79): 294-321.
https://doi.org/ 10.1006/jecp. 2000.2587
[72] Gathercole SE, Alloway TP, Willis C, et al. Working memory
in c hildren with reading disabiliti es. J Exp Child Psychol
2006; (93): 265-281.
https://doi.org/ 10.1016/j.jecp.2005.08.003
[73] Lynn R, Irwing P. Sex differe nces on the progressive
matrices: A meta-an alysis. Intell igence 2004; (32): 481-498.
https://doi.org/ 10.1016/j.intell.2004.06.008
[74] Steinmayr R, Beauducel A, Spinath B. Do sex differences in
a faceted model of fluid and crystallized intelligenc e depend
on the method applied? Intelligence 2010; (38): 101-110.
https://doi.org/ 10.101 6/j.intell.2009.08.001
[75] Lynn R. Sex differences in intelligence: The developmental
theory. Mankind Quarterly 2017; (58): 9-42.
[76] Sokołowski A, Tyburski E, S ołtys A, et al. Sex Differences in
Verbal Fluency Among Young Adults. AC Psych 2020; (16):
92-102.
http://doi.org/10.5709/acp-0288-1
[77] Pezzuti L, Tommasi M, Saggino A, et al. Gender diff erences
and measurement bias in the assessment of adult
intellige nce: Evidence from the Italian WAIS-IV and WAIS-R
standardizations. Intelligence 2020; 79.
https://doi.org/ 10.1016/j.intell.2020.101436
[78] Mortensen E, Sørensen H, Jens en H, et al. IQ and mental
disorder in young men. BJ Psych 2 018; (187): 4 07-415.
https://doi.org/ 10.1192/bjp.187.5.407
[79] Braatveit KJ, Torsheim T, Hove O. The Prevalence and
Characteristics of Intellectual and Borderline Intellectual
Disabilities in a Sample of Inpatients with Substance Use
Disorders: Preliminary Clinical Results. J Ment Res In 2018;
(11): 203-220.
https://doi.org/ 10.1080/19315864.2018.1469701
[80] De Oliveira MO, Nitrini R, Yassuda MS, Brucki SM.
Vocabulary is an appropriate measure of premorbid
intellige nce in a sample with heterogeneous educational level
in Brazil. Behavioural Neurology 2014; 875960.
https://doi.org/ 10.1155/2014/875960
[81] Adams HE, Sutker PB Eds. Comprehensive handbook of
psychopathology. Springer Science & Business Media 2007.
[82] Latvala A, Cas taneda AE, Perälä J, et al. Cognitive
functioning in substance abuse and dependence: a
population‐based study of young adults. Addiction 2009;
(104): 1558-1568.
https://doi.org/ 10.1111/j.1360-0443.2009.02656.x
[83] Luczak SE, Yarnell LM, Prescott CA, et al. Childhood
cognitive measures as predictors of alcohol use and
problems by mid-adulthood in a non-Western cohort.
Psychology of Addictive Behaviors 2015; (29): 365-370.
Available from:
https://doi.org/ 10.1037/adb0000043
[84] Jankowska AM, Bogdanowicz M, Takagi, A. Stability of the
WISC-R scores in students with borderline intellectual
functioning. Health Psychol 2014; (2): 49-59.
https://doi.org/ 10.5114/hpr.2014.42789
[85] Orsini A, Pezzuti L. WAIS-IV. Contributo alla tar atura italiana.
Firenze: Giunti OS 2013.
Received on 27-09-2023 Accepted on 05-12-2023 Published on 25-01-2024
https://doi.org/ 10.6000/2292-2598.2023.11.05.1
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