Rev Bras Psiquiatr. 2011;33:390-399
Volume 33 • Número 4 • Dezembro/2011
Introduction: Obsessive-compulsive disorder (OCD) is a heterogeneous condition, in which
subtypes have been proposed. Previous studies suggested that gender plays a relevant role in OCD
phenotypic expression. This study aimed to review the literature on gender differences in clinical,
genetic or familial aspects of OCD. Method: A conventional review was conducted, including all
papers that investigated demographic, clinical, and genetic aspects of OCD according to gender.
The search was based on data available in Medline and PsycINFO databases in the last 20 years,
using as keywords: obsessive-compulsive disorder; and: gender, sex, male, female, demographic
characteristics, clinical features, clinical characteristics, genetic, genes, genetics gender OCD,
genes OCD, genes OCD males, genes OCD females. Results: Sixty three of 487 phenotypical and
genetics studies were selected. Most studies indicate that male patients are more likely than
females to be single, present early onset of symptoms and chronic course of the disorder, greater
social impairment, more sexual-religious and aggressive symptoms, and greater comorbidity with
tic and substance use disorders. Female patients present more contamination/cleaning symptoms
and greater comorbidity with eating and impulse-control disorders. Genetic and family studies
are inconclusive, but suggest that gender may play a role in the disease expression. Conclusions:
Gender is a relevant factor that should be taken into account when evaluating OCD patients.
More studies are necessary to determine whether in fact it defines a homogeneous and particular
group in OCD.
©2011 Elsevier Editora Ltda. All rights reserved.
Gender differences in obsessive-compulsive disorder:
a literature review
Maria Alice de Mathis,1 Pedro de Alvarenga,1 Guilherme Funaro,1
Ricardo Cezar Torresan,2 Ivanil Moraes,1 Albina Rodrigues Torres,2
Monica L. Zilberman,1 Ana Gabriela Hounie1
1 Department of Psychiatry, Universidade de São Paulo (USP), São Paulo, Brazil
2 Department of Neurology, Psychology and Psychiatry, Botucatu Medical School,
Universidade Estadual Paulista (Unesp), Brazil
Received on July 13, 2011; accepted on July 31, 2011
Corresponding author: Maria Alice de Mathis; Departamento de Psiquiatria, Faculdade de Medicina da USP; Rua Dr. Ovídio Pires de Campos, 785,
CEAPESQ, sala 7; 05403-010 São Paulo, SP , Brazil; Phone: (+55 11) 30697896; Fax: (+55 11) 30697895; E-mail: email@example.com
1516-4446 - ©2011 Elsevier Editora Ltda. All rights reserved.
391 Gender differences in obsessive-compulsive disorder: a literature review
Diferenças de gênero no transtorno obsessivo-compulsivo: uma revisão da literatura
Introdução: O transtorno obsessivo-compulsivo (TOC) é um quadro heterogêneo, no qual subtipos
têm sido propostos. Estudos anteriores sugerem que gênero desempenha papel relevante na
expressão fenotípica. O objetivo foi realizar uma revisão convencional da literatura sobre
diferenças de gênero em relação a aspectos clínicos e genéticos ou familiares do TOC. Método:
Realizou-se uma revisão convencional da literatura incluindo todos os artigos que investigaram
aspectos sociodemográficos, clínicos e genéticos do TOC, de acordo com o gênero. A pesquisa
foi baseada em publicações disponíveis nas bases de dados Medline e PsycInfo nos últimos 20
anos, usando como palavras-chave: obsessive-compulsive disorder (OCD), e: gender, sex, male,
female, demographic characteristics, clinical features, clinical characteristics, genetic, genes,
genetics gender OCD, genes OCD, genes OCD males, genes OCD females. Resultado: Sessenta e
três artigos de fenótipo e genética foram selecionados. Na maioria dos estudos, o sexo masculino
associou-se mais que o feminino com: ser solteiro, apresentar início mais precoce dos sintomas,
maior prejuízo social, mais sintomas sexuais, religiosos e de agressão, e mais comorbidade
com transtorno de tiques e abuso de substâncias. Pacientes do sexo feminino apresentam mais
sintomas de contaminação/limpeza e mais comorbidade com transtornos alimentares e do controle
de impulsos. Estudos genéticos e familiares são controversos, mas indicam que o gênero pode
desempenhar um papel na expressão da doença. Conclusão: Gênero é um fator relevante a ser
considerado na avaliação de pacientes com TOC. São necessários mais estudos para determinar
se este fator define de fato um grupo homogêneo e particular de TOC.
©2011 Elsevier Editora Ltda. Todos os direitos reservados.
Identidade de gênero;
Obsessive-Compulsive Disorder (OCD) is the fourth
most prevalent psychiatric disorder in the United
States.1 Epidemiological studies conducted in several
countries reported current prevalence around 1% and
lifetime prevalence ranging from 2% to 3%.2 Regarding
gender, a bimodal distribution of age of onset has been
described. Studies assessing pediatric samples report male
preponderance (70%), whereas adult studies report equal
gender distribution or a slight female preponderance.3 Males
usually report early-onset of obsessive-compulsive symptoms
(OCS) and association with tic disorders, attention deficit,
and hyperactivity disorder (ADHD).4,5
OCD is a very heterogeneous disorder, and gender
differences may help identify more homogeneous
subgroups. This strategy may enhance our understanding
of the pathophysiology of OCD, including gene-environment
interactions.6 Also, as a considerable proportion of OCD
patients is not responsive to first line treatments,7 the
identification of more homogeneous subgroups may lead to
more tailored and effective treatments.8 Until now, some OCD
subgroups have been proposed based on age of OCS onset,
presence of tics, and history of streptococcal infection.8,9
Gender has been shown to play a vital role in
neurobiological aspects, psychosocial factors, and behavioral
patterns in several psychiatric disorders. Whereas sex is a
concept focused on biological aspects, gender is a broader
concept, including a range of psychosocial aspects (e.g.
attitudes, feelings, values, behaviours, and activities) that,
through a process of social construction, differentiate men
and women.10 Recent studies of OCD clinical samples suggest
that gender moderates the genetic expression of this complex
disorder, resulting in specific phenotypes.11-14
The aim of this study was to conduct a two-decade
conventional literature review of gender differences in
demographic, clinical, and genetic aspects of OCD.
A conventional review of gender (or sex) differences in
OCD patients was conducted, including all epidemiological,
clinical, neuropsychological, and genetic or familial studies
available in Pubmed and PsycINFO databases between January
1990 and August 2010. Only articles published in English and
Portuguese were included. The phenotypical studies search
strategy included the following keywords: obsessive-
compulsive disorder (OCD) and: gender, sex, male, female,
demographic characteristics, clinical features, clinical
characteristics. Initially, 343 studies were found, but only 39
of them were included in the present review, as most articles
(N = 304) did not specifically address gender differences
and were therefore excluded. A few references cited in the
selected articles that had not been previously found and that
were considered pertinent were also included.
To investigate genetic or familial aspects, the following
key words were used: obsessive-compulsive disorder (OCD)
and genetic(s), genes, gender OCD, genes OCD, genes OCD
males, genes OCD female, gene OCD male. Twenty-four
genetic studies from a pull of 144 articles were finally
included in this study (Figure 1).
392M.A. Mathis et al.
Several studies describe an earlier OCD onset among male
patients, compared to femaless.14,15 Approximately one
third of adult patients refer symptom onset in childhood26
and, among children, two thirds of cases are boys.3,13,27-28
Fontenelle et al. evaluated possible differences in Brazilian
patients with early (up to 17 years of age) and late onset,
confirming the predominance of men in the first group,
which presented higher clinical severity when compared
to the latter.20 In another study conducted in Brazil of 330
patients, men also prevailed in the early onset group (up to
11 years of age).29 An Italian study found a higher frequency
of insidious onset and chronic course among male sufferers
and more episodic course among females.19
According to Noshirvani et al.,17 similarly to schizophrenia,
OCD cases with an early onset are usually more severe,
reflecting the influence of cerebral lesions or constitutional
aspects to which men are more vulnerable than women.
Likewise, Bogetto et al.19 consider that early OCD onset is
not strongly related to the impact of stressful life events but,
conversely, could indicate a higher influence of biological
lesions to which men are more predisposed. Biological
theories propose that damage occurring during pregnancy is
more global than that occurring after birth, and that the rapid
growing organs are more vulnerable. Boys would be more
susceptible than girls to developmental damage because
among humans and other animals females are biologically
stronger compared to males.30 A more accelerated growth of
the prefrontal cortex (PFC) was observed between 8 and 14
years of age,31 a period in which most cases of OCD begin in
childhood. This finding indicates that abnormal development
of these structures could be related to early onset of
symptoms.32 As the PFC continues to mature throughout adult
life, abnormalities in later maturation processes could be
related to late-onset OCD. Because the development of the
caudate nucleus and the orbitofrontal cortex (OFC) — two
central components of the OFC/ACC (anterior cingulate
cortex) loop — is different for boys and girls, this could
explain, at least in part, the higher prevalence of early-onset
OCD among boys.32
Sobin et al.33 found some indirect indicators of a higher
negative impact of OCD among male sufferers. For example,
two thirds remain single versus only one third of women.
Moreover, almost half of male patients continued to live with
their original families or in assisted homes, compared with
only 20% of women. Torresan et al.25 described earlier age of
symptom interference among Brazilian men, who were also
more likely than women to be single, which is consistent with
findings from other countries.18,23,34 Several other authors have
also described that women with OCD are more frequently
married than men.14,22-24 Matsunaga et al.,34 evaluating 94
Japanese patients, found higher social interference of OCS
among men, whereas women more frequently involved
family members in their rituals. Therefore, an early onset
among males can lead to a higher impact on several areas
of daily life, including social adjustment and interpersonal
relationships, which may be indirectly indicated by the lower
rates of marriage in this population.
Differences in the content of OCS between genders
have also been described in studies conducted in Spain,
Italy, France, India, and Turkey. Women are more prone
to contamination obsessions,22 usually associated with
cleaning rituals;6,19,23,24 whereas sexual obsessions are more
common among men.19,22,23,35 Several studies combine rates
of sexual and religious symptoms, which are more frequent
in males.6,24,36 Results are inconclusive regarding aggressive
obsessions, with studies showing varying predominance
between genders.22,36,37 In male, symmetry obsessions would
be more common,23,24,38 as well as ordering,36,38 repeating,19
checking,23 and hoarding compulsions.39,40,41
Torresan et al.25 found among Brazilian men more sexual,
religious, and symmetry obsessions, as well as more mental
rituals. Chacon et al.42 evaluated OCD symptom dimensions
in 40 pairs of Brazilian siblings with OCD. When both
siblings were male, there was a significant correlation with
contamination obsessions and cleaning rituals; and when
both siblings were female, a correlation was found with
The higher frequency of aggressive obsessions among
women,37 which are usually characterized by fear of losing
control, could be related to motherhood and fear of causing
some harm to the newborn.37 Different ways of clustering
symptoms hamper the comparisons between OCD studies to
some extent. Some of them, for example, analyze aggressive
obsession along with sexual and religious obsessions,36,38-42
which are more common among males. Such symptoms are
called by some authors “forbidden” or “taboo” thoughts,43
usually manifested as ego-dystonic impulses. Aspects related
to sexuality are particularly complex, involving a constant
interaction between biological, psychosocial, and cultural
factors, which are remarkably divergent between genders.
Likewise, the predominance of contamination-cleaning
symptoms among females, a finding almost universal in
OCD phenomenological studies, probably involve biological,
psychological, and sociocultural aspects related to the
female role in different societies. Mataix-Cols et al.,44 in a
functional neuroimaging study during a provocation task of
487 INITIAL ARTICLES
343 PHENOTYPICAL ARTICLES
24 SELECTED GENETIC
144 GENETIC ARTICLES
Figure 1 Fluxogram of the articles included in this revision.
304 EXCLUDED*120 EXCLUDED**
* Did not specifically address sex or gender differences.
** Did not specifically address genetic differences.
393 Gender differences in obsessive-compulsive disorder: a literature review
cleaning symptoms, described a greater activation of areas
such as ventromedial prefrontal regions, medium temporal
gyrus, right caudate nucleus, medium frontal gyrus, and
left cingulus antero-dorsal gyrus in OCD patients, when
compared to normal controls. A study of individuals without
any psychiatric disorder suggested that the same cerebral
areas contain a large number of sex hormone receptors, with
relevant sexual dimorphism, with women presenting larger
volumes of these structures.45 According to Labad et al.,6 this
finding could at least partially explain the greater proportion
of women with these symptoms.
Regarding psychiatric comorbidities in OCD, some of
them seem to be more associated with one gender than the
other.46 According to some authors, more women present
co-occurring major depressive disorder.6,23,33 On the other
hand, several studies found no gender differences regarding
major depression comorbidity, which is the most common
Axis I disorder in both genders.21,22,24,25,37,47 In an Italian
study,19 men presented more social phobia, tic disorders,
and hypomania episodes. In Brazil, Torresan et al.25 found
more posttraumatic stress disorder and tic disorders among
men, whereas women presented more simple phobias,
eating disorders (anorexia nervosa), as well as more impulse
control disorders in general, particularly skin picking and
“compulsive” shopping.25 Another Brazilian study47 compared
OCD patients with and without alcohol use disorders and
found more men in the first group, in accordance with other
studies.19,33 Men also presented more chronic tics and Tourette
syndrome (TS), a clinical aspect that overlaps with early
onset of OCS.9 Besides substance use disorders, men were
more likely to present attention deficit, hyperactivity, social
phobia, affective, and anxiety disorders in general.24,25,48
Some gender-related comorbidity findings in OCD, such as
substance use and social phobia among men, and eating and
impulse control disorders among women, seem to reflect a
general trend of clinical samples with other mental disorders,
as well as community samples. Therefore, it is noteworthy
that major depression usually does not predominate among
women with OCD, possibly indicating that depressive
symptoms are intrinsically linked to OCS regardless of gender.
The results of the main clinical studies assessing OCD
clinical features and gender are summarized in Table 1.
Several genes of serotoninergic, dopaminergic, and other
systems have been implicated in OCD pathogenesis, based
on theories derived from treatment response to medications
that exert effects on those pathways.
Table 2 presents the main findings for genetic differences
between genders in OCD. The discussion will not focus
on each individual study, as the main findings for each
individual are summarized in the above-mentioned table.
As for methodological details, they can be found in the
original articles. For some studies, when genotypic data was
available, we reanalyzed the allelic frequencies. Thus, some
findings published as “trends” were not included by us as
positive results (e.g., study 50) if after our reanalysis they
turned to be negative (Izbicki et al., submitted).
The results of association or family-based studies are
inconclusive, with some rendering positive associations
with one gender, others negative and even some with
positive findings for the opposite sex regarding several
polymorphisms of candidate genes. Candidate genes in the
serotonergic pathway were more frequently studied due
to the consistent response of OCD to selective serotonin
reuptake inhibitors (SSRI). However, findings have not been
conclusive. For example, the same polymorphism of the gene
5HT1Dbeta [Single Nucleotide Polymorphism (SNP) G861C]
was associated with OCD in males in two studies, one found
association with the C allele,21 and the other with the G
allele.49 However, the second study49 evaluated only males,
not allowing an unequivocal association. On the other hand,
OCD in women, but not in men, was associated with the A
allele of the -1438G>A polymorphism of the promoter region
of 5-HT2A50 and the short allele of 5-HTTLPR.51 However
Wendland et al.52 found no association between OCD, gender
and three other functional polymorphisms of the serotonin
transporter gene (5-HTTLPR, STin2, and rs25531),52 despite
using a larger sample than the one used by Denys et al.,53
which also found an association between the short allele of
5-HTTLPR and women with OCD.53
Dickel et al.54 also found an association between woman
with OCD and the 5-HTTLPR long allele polymorphism,
although, after correction for multiple testing, the finding
lost significance.54 Although no individual study has been
replicated, a pooled analysis of five TDT replication studies
of the SLC6A4 5-HTTLPR polymorphism supports association
(p = 0.02) between OCD and this polymorphism.
In the most recent study of SLC6A4 in OCD, Voyiaziakis et
al.55 genotyped 1241 individuals from 278 families for 13 SNPs
in the polymorphic region (LPR) indel (insertion/deletion)
including haplotypes of the rs25531, VNTR polymorphisms
in introns 2 and 7, and for a 381 bp deletion in the 3´
portion of LPR. Data were analyzed with the Family Based
Association Test (FBAT) and after sex stratification, women
were associated with alleles 9/10 of the Int2 (p < 0.0002).55
This was the most significant finding in terms of statistical
outcomes, which remained significant even after correction
for multiple markers. The authors mentioned that many
alleles related to the Int2 marker are associated with
neuropsychiatric disorders, and as the majority of the
affected individuals were women (66%) and there were
differences due to gender in the prevalence of several Axis I
disorders (women more affected with major depressive
and panic disorders), it is plausible that the association
observed with 9/10 alleles of Int2 VNTR in the sample may
be explained by other Axis I disorder rather than by OCD.
The most plausible explanation so far for the discrepancy in
the findings lies in the small size of the sample.
An interesting finding is the association between MAOA
gene variants and OCD. The monoamine oxidase is responsible
for the oxidation of biogenic amines. Additionally, the gene
encoding MAO-A is located on the X chromosome. There are
few functional MAOA polymorphisms that have been studied
in OCD: one is a 30 bp VNTR in the encoding region (intron
1); another is a T to G substitution in the exon 8 (T941G)
that, despite not leading to aminoacid change, results in high
enzymatic activity; and a third is a T to C silent substitution
in exon 14, in which the T allele is related to lower enzymatic
activity (C1460T/EcoRV). Karayiorgou et al.56 and Lochner et
al.21 have found an association, in independent studies and
with independent polymorphisms, between men with OCD
394 M.A. Mathis et al.
Table 1 Main results of the clinical studies on obsessive-compulsive disorder and gende
Authors and year
N total (n ♂; ♀)
Minichiello et al.16
138 (67; 71)
[6 - 68]
Earlier onset of OCD, more
obsessions without compulsions
More cleaning compulsions
Noshirvani et al.17
307 (137; 170)
[16 - 67]
DSM-IIIEarlier onset of OCD, more likely to
be single, more checking compulsions
and alcohol dependence
More cleaning compulsions,
depression, and anorexia
Castle et al.14 219 (93; 126)
DSM-III-R Earlier onset of OCD More cleaning compulsions, more likely
to be married and to have children
Hantouche et al.36
646 (261; 385)
DSM-III-R Higher severity of OCS/OCD, more
sexual, religious and aggressive
obsessions, symmetry-ordering rituals,
hypochondriasis and paraphilias
More checking compulsions, eating
disorders, and “compulsive” shopping
Lensi et al.37
263 (112; 151)
[11 - 71]
DSM-III-R Earlier onset of OCD,
More sexual and symmetry-
exactness symptoms, bizarre rituals,
hypomania, and alcohol abuse
More aggressive obsessions, cleaning
compulsions, and panic attacks post OCD
Bogetto et al.19
160 (76; 84)
Y-BOCS ≥ 16
OCS and OCD earlier onset, higher
severity of obsessions, more sexual
and repetitive symptoms, social
phobia, hypomania, depersonalization,
and substance use disorders
More contamination and cleaning symptoms,
anorexia and impulse control disorders
Sobin et al.33
100 (44; 56)
DSM-IVMore likely to be single and living with
the original families or in assisted
homes, more sexual obsessions,
and substance use disorders
Fontenelle et al.20 69 (32; 37)
[18 - 65]
ICD-10Earlier onset of OCD and higher
global severity at the onset (CGI)
Higher severity of depressive
symptoms at the onset (BDI)
Lochner et al.21
220 (107; 113)
[18 - 75]
DSM-IVEarlier onset of OCD, more
unemployment, aggressive obsessions,
and substance use disorders
More anorexia, bulimia, simple
phobia, and depression
Tukel et al.22
169 (73; 96)
[16 - 60]
Earlier onset of OCD, higher educational
level, more sexual, aggressive, and checking
symptoms, social phobia and schizophrenia
More likely to be married, higher severity
of compulsions (YBOCS), and more
contamination and cleaning symptoms
Karadag et al.23
141 (41; 100)
[16 - 73]
DSM-IV Earlier onset of OCD, more sexual,
symmetry, and checking symptoms,
tics and bipolar disorder
More likely to be married, more contamination
and cleaning symptoms, and depression
Labad et al.57
186 (114; 72)
DSM-IV More sexual and religious obsessionsHigher severity of OC (YBOCS),
depressive (HAM-D) and anxious (HAM-A)
symptoms, more contamination and
cleaning symptoms, and depression
Jaisoorya et al.24
231 (166; 65)
DSM-IV Earlier onset of OCD, more religious
and symmetry symptoms, and ADHD
More likely to be married, more
cleaning rituals and trichotillomania
Li et al.38
DSM-IVMore symptoms of the symmetry-
More symptoms of the contamination-
Torresan et al.25
330 (182; 148)
[10 - 72]
DSM-IVEarlier onset and interference of OCS,
more likely to be single, higher educational
level, more sexual and religious obsessions,
symmetry and mental rituals, PTSD and tics
Higher severity of depressive (BDI) and
anxious symptoms (BAI), more simple
phobia, anorexia, impulse control disorders,
“compulsive” buying, and skin picking
BDI: Beck Depression Inventory; BAI: Beck Anxiety Inventory; HAM-A; Anxiety Hamilton Scale; HAM-D: Depression Hamilton Scale; OCS: Obsessive-
compulsive symptoms; OCD: Obsessive-compulsive disorder; PTSD: Posttraumatic Stress Disorder; ADHD: Attention deficit and hyperactivity disorder.
395Gender differences in obsessive-compulsive disorder: a literature review
and high activity alleles of the MAO-A gene. Camarena et al.58
and Lochner et al.,21 pointed towards an association between
low activity MAO-A alleles and woman with OCD. These
findings depict a probable example of sexual dimorphism,
although its significance is currently not clear, as IMAOs are
not as effective as SSRIs in OCD treatment and the outcomes
found were based on small samples and different populations.
Another explanation for the disparity of the findings is
that the studied polymorphisms were close to the “true”
polymorphism possibly associated with OCD, although they
are not, per se, responsible for OCD.
The COMT gene (catecol-O-metil transferase) encodes a
homonymous enzyme, which also metabolizes monoamines,
with particular importance for dopamine in the prefrontal
cortex.59 The COMT gene has several allelic variations,
including the most studied polymorphism Val158Met, which
is a functional SNP(G158A) of this gene, resulting in a
substitution of valine (high activity allele) to methionine
(low activity allele). In a study of 110 OCD families,
Karayiorgou et al.56 found a sexually dimorphic association
between a low enzymatic activity variant of the COMT gene
and OCD males. This finding is consistent with a previous
study11 in which the same association between OCD and Met
allele was mentioned, although in a smaller sample. However
Schindler et al.,60 Alsobrook et al.,61 Katerberg et al.,59 and
Denys et al.51 have not found differences due to gender in
the allelic or genotypic frequencies, although Katerberg
et al.,59 found that women with the val-met genotype had
lower scores in somatic- sensorial phenomena. Pooley et al.62
found a trend towards a higher frequency of the Met allele
in OCD males, although genotypic data were not published,
which did not allow us to confirm the finding.62 But this
meta-analyses, based on data from all case-control studies
published (n = 1,908 patients) showed association between
the 158met allele and OCD in males (OR = 1.88, 95% CI
1.45-2.44, p < 0.001). Wang et al. (2009) in a COMT gene
expression study found that not only did OCD patients present
a lower expression of the COMT gene, in relation to controls,
but also women had lower expression than men.63 The main
controversial point of this study is that plasma levels of COMT
do not necessarily reflect what occurs in the CNS, leaving
the interpretation of the present results for future studies.
Kinnear et al.64 failed to detect statistical significance in their
sample stratified by gender when studying the association
between a new polymorphism (Cà T transition) in the COMT
gene, its levels of enzymatic activity, and the regulation by
estrogen through the estrogen responsive elements in the
promoter region of this gene in OCD patients.64 The positive
findings are biologically plausible: compared to val-COMT,
met-COMT individuals performed less well on tests of task
shifting, had an electrophysiological profile indicative
of decreased flexibility of prefrontal neural processing,
and showed greater amygdala-orbitofrontal connectivity
in response to negative emotional stimuli suggestive of
inflexible emotional processing. It may be speculated that
the stability and relative inflexibility of neural processing
associated with met-COMT may become excessive, and
thereby render the individual vulnerable to obsessions and
compulsions. Anatomically, although COMT functionality
is thought to be predominantly cortical, the val158met
polymorphism also influences striatal dopamine activity,
and may thus influence both cortical and subcortical levels,
signaling within the corticostriatal loops that underlie the
pathophysiology of OCD.
Denys et al.,53 studying dopamine gene receptors in a
sample of 300 patients, half of them with OCD and half
controls, concluded that male OCD patients expressed a
predominance of A2A2 genotypes (p = 0.049), as well as the
A2 DRD2 allele (p = 0.020).53 This genetic link, supporting
the association of the dopaminergic system with the
pathophysiology of OCD and a dimorphic pattern due to
gender, was not found while investigating the association
between the polymorphism located in the intron 8 of the
dopamine transporter gene (SLC6A3 or DAT1) and OCD in a
Brazilian sample of 208 patients and 865 healthy controls.65
The positive finding of Denys et al. (2006) needs replication
as it is difficult to interpret: the association of the A2 allele
with the OCD sample was unexpected and the A1 allele of
the DRD2 TaqI A system has been found to be associated with
a variety of addictive, impulsive, and compulsive disorders.
The studies of the genes in the glutamatergic system
found a positive association between OCD, several SNPs, and
haplotypes in the gene encoding the glutamate transporter,
more associated with men with OCD, according to family-based
studies. Although the associated SNPs have not been the same,
all of them point towards the need for biological validation of
the findings, as these have been the most consistent findings
in the genetic research of OCD.66-69 Moreover, although the
stratified analysis by gender status in Shugart et al.69 indicated
that the male-only analysis showed more significant results
than the female-only analysis in our samples, the pooled data
set showed the strongest results. Therefore, their finding
may not strongly support the results reported by the other
three independent groups in which only the families with
male probands contributed to the significant association of
signs, which generally suggests an association with OCDl.
Increasing evidence from several lines of study implicate a
role for glutamatergic neurotransmission in OCD. Cerebrospinal
fluid levels of glutamate have been shown to be increased in
a sample of adult OCD patients compared to controls, and
decreased glutamate levels have been reported following
a successful paroxetine trial. Furthermore, successful
preliminary open-label trials of two glutamatergic modulating
agents (riluzole and n-acetylcysteine) have been reported.66
Finally, a few studies that searched for association
between BDNF gene polymorphism and OCD also reported
Wendland et al.52 and Dickel et al.54 found no association
between BDNF gene polymorphism and OCD, even after
gender stratification.52,54 However, Alonso et al.70 in a sample
of 215 OCD patients and 342 controls, found a significant
association between the SNP (rs2378672) in the BDNF receptor
gene (neurotrophic tyrosine kinase receptor type 2- NTRK2)
and OCD in women (p < 0.0001).70 Katerberg et al.59 found
that the BDNF’s genotype Met66Met might be associated with
a mild phenotype in Dutch women (but not in South Africans),
and that the BDNF Val66Val genotype and the Val66 allele
may have a role in sexual and religious obsessions.59
Hemmings et al.,71 who investigated the variant val66met in
the BDNF gene, showed an association between the met66 allele
and the male gender, as well as an association with early onset
OCD. However, the genotype val66val was associated with more
396 M.A. Mathis et al.
Table 2 Main results of genetics studies on obsessive-compulsive disorder and gender
Author; Year Males Females
Karayiorgou et al.56
- Men with OCD associated with the low activity allele in a recessive form
- High activity G allele (MAOA*297CGG) in a subsample of male OCD patients with depression
(n = 47)
- No significant association was found with females
(n = 56)
Schindler et al.60
-No difference in genotypes was found between genders regarding the gene SLC1A1
(males n = 101) (females n = 115)
Kinnear et al.64
- The C-T transition adjacent to ERE 6 in the promoter area of COMT and OCD was not significantly associated with OCD (p = 0.93) or gender (p = 0.67)
(males n = 45) (females n = 51)
Enoch et al.50
- No significant differences between male probands and controls in (-1438G>A)
(n = 53 OCD x 61 controls)
- Female probands associated with A allele of polymorphism
(-1438G>A) of 5-HT2A
(n = 48 OCD x 77 controls)
Camarena et al.58
- OCD men associated with allele 2 but not confirmed by TDT
(n = 63)
- Women with OCD and depression associated with allele 1 of MAOA/EcoRV
(T, low activity)
(n = 59)
Alsobrook et al.61
- No significant differences found in male probands compared to controls
(males n = 104) (females n = 120)
Lochner et al.21
- Caucasians expressed high activity T allele of EcoRV variant of MAO-A-(C1460T/EcoRV) gene
(n = 52 OCD x 21 controls)
- Afrikaners frequently homozygous for C allele (variant G861C) of 5HT1Dbeta gene.
(n = 37 OCD x 20 controls)
- Caucasians: most homozygous for low activity C
allele of MAOA (C1460T/EcoRV) gene.
(n = 43 OCD x 73 controls)
Arnold et al.68
-2 SNPs (rs301434; rs301435)
- Located in the SLC1A1gene area (glutamate transporter) were associated with OCD transmission
- (Haplotype C-G) was associated with transmission in OCD
(n = 191)
- No significant association was found in studied areas
(n = 285)
Denys et al.53
- No association was found with 5-HTTLPR polymorphism
(n = 56 OCD)
- Short allele (S) of 5-HTTLPR was associated with OCD in females
(n = 100 OCD)
Denys et al.51
- Predominance of genotype A2A2 of dopamine receptor (DRD2)
(n = 51 OCD x 67 controls)
- Predominance of A2 allele (DRD2) expression
- No differences found between male probands and controls for COMT gene
- No differences were found between female
probands and controls for DRD2
(n = 88 OCD x 66 controls)
(n = 99 OCD x 71 controls)
Dickel et al.54
- Probands presented significant association with SNP rs3780412 in SLC1A1 gene (p = 0.002)
and association with T/C haplotype of SNPs rs301430; rs301979 (p = 0.003)
(n = 373)
- no differences found in females
(n = 375)
Miguita et al.65
- No association nor differences between sexes in relation to polymorphism of dopamine gene transporter (SLC6A3) and OCD
(males n = 720) (females n = 353)
Wendland et al.52
- No differences between sexes according to serotonin transporter gene (SLC6A4) (and its functional polymorphisms 5-HTTLPR, STin2 and rs25531) and BDNF gene.
((n = 347 OCD x 749 controls)
Dickel et al.67
- No significant differences in genes SLC6A4,HTR1B,HTR2A and BDNF
n = 54 trios
Stewart et al.66
- Three haplotypes related to SCL1A1 gene: rs12682807/ rs2072657/
rs301430, higher transmission of a/a/t in OCD males
(n = 47)
- No significant differences found between female probands and controls
(n = 19)
Pooley et al.62
-Trend to a higher frequency of the met allele of the COMT gene in men with OCD
(n = 30 OCD x 137 controls)
- No association between met COMT allele gene in women with OCD
(n = 57 OCD x 190 controls)
Hemmings et al.71
- 66met allele of the codifying gene of BDNF was associated with early-onset OCD in males
(n = 140)
-Val66val genotype was associated with severe OCD in females
(n = 140)
Alonso et al.70
- No significant differences found between male probands and controls
(n = 103 OCD x 202 controls)
- The SNP (rs2378672) of gene (NTRK2) was higher
in women with OCD compared to controls
(n = 112 OCD x 140 controls)
Shugart et al.69
- Strong association (p < 0.0001) between SNP rs301443 (gene
SLC1A1) and relatives of male OCD probands
(n = 379)
- Trend of association (p = 0.076) with SNP rs301443
(gene SLC1A1) in relatives of female OCD probands
(n = 627)
Katerberg et al.59
- Polymorphism Val/met of BDNF in association with men
(n=200 OCD x 278 controls)
-In females with OCD, the Met66Met genotype was associated with later
age of onset and a trend for a negative family history, whereas the Val66Val
genotype showed a trend for association with lower YBOCS severity scores.
(n=219 OCD x 372 controls)
Katerberg et al.72
-No association with 158Met COMT allele gene in OCD males
(n = 151 OCD x 235 controls)
- No association with 158Met of COMT gene in females
- Women with Val-Met genotype presented lower scores
in somatic symptoms and sensory phenomena
(n = 222 OCD x 227 controls)
Wang et al.63
- Men presented increased COMT gene expression compared to females
- OCD males had 38% of downregulation in expression of COMT genes compared with controls
(n = 36)
- Women presented decreased COMT gene expression compared to males
- OCD women presented 27% of downregulation in
COMT gene expression compared with controls
(n = 30)
Kim et al.49
- Increased expression of allele G861 of receptor 5-HT1Dbeta in male probands
(n = 167 OCD x 107 controls)
- Study was not conducted with females
(n = 0)
Voyiaziakis et al.55
- No association with polymorphism in SLC6A4
(n = 484)
- Females were associated with 9/10 of Int2 alleles (p < 0.0002)
(n = 742)
397Gender differences in obsessive-compulsive disorder: a literature review
severe OCD in females. BDNF has been implicated in neuronal
survival and in activity-dependent neuroplasticity. Studies in
knockout mice as well as those using B cell lines suggest that
BDNF modulates the serotonin transporter function. Although
the BDNF gene is an attractive OCD candidate gene, from both
brain development and neurotransmitter perspectives, the
findings are still controversial.
Despite the fact that almost ten years have passed since
the beginning of the Genome Project and the hope that
genes involved in several diseases would be easily found, the
results of genetic psychiatric studies remain inconclusive.
These dissonant findings are typical of association studies of
complex diseases carried out in different populations. The
low rate of replication of these studies could be explained by
methodological problems, such as differences in phenotypical
definition and small statistical power of the studies. It has
become clear over time that without establishing more
homogeneous and valid subgroups and without the correct
identification of the inherited phenotypes, molecular
genetics by itself will not be able to identify the susceptible
genes for OCD. Moreover, not only larger samples are required
for association studies of the entire genome, but also a search
for psychopathological and clinical inherited features and the
characterization of homogeneous subgroups with consistent
genetic validation. Finally, it should be borne in mind that
genetic studies are the key to understanding the interaction
between genes and environment, and that all efforts
towards molecular studies are in vain if the phenotype and
environmental factors are not carefully examined in advance.
This literature review points to some consistent differences
between genders regarding OCD phenomenology, as well
as to possible genetic differences regarding susceptible
polymorphisms. The study of these differences may lead
to the definition of more homogeneous phenotypes and
contribute to the elucidation of etiological factors and
development of new treatments. The investigation of
OCS using the recently developed dimensional approach,73
which combines obsessions and compulsions that more
frequently co-occur, may bring relevant contributions to
the understanding of this heterogeneous disorder.6 The
importance of such investigation is reinforced by studies that
described considerable differences in neuroimaging results
for different OCD symptom dimensions.74,75
In summary, gender may be a relevant factor to determine
OCD clinical presentation and course, and may be considered
to define more homogeneous subgroups. Although the reasons
why OCD presentation differs between genders are not clear,
one may speculate that they result from both biological and
psychosocial influences. Among the biological factors, sex-
linked genetic features and hormonal differences may be
cited. Considering psychosocial aspects, gender-related social
roles may affect the content of obsessions and compulsions.
While age of onset seems to be a more genetic characteristic
influenced by family history of OCD, the occurrence of sexual
and aggression symptoms may be influenced by hormonal
characteristics, as well as by gender role. For instance, it
is widely accepted that testosterone levels influence sexual
drive and preoccupations, impulsivity and aggressive behavior.
Thus, regardless of the causes of gender differences found in
patients, it is important to address this issue when it comes
to the evaluation and treatment of OCD. Further studies
are necessary to determine whether in fact gender defines
a particular OCD subgroup. Phenotypical, epidemiological,
genetic, family, neuroimaging, neuropsychological, and
intervention studies taking into account aspects of gender
differences may add to the understanding of OCD etiological
mechanisms and possibly also to the development of more
specific and effective therapeutic approaches.
Maria Alice de Mathis
Employment: Faculdade de Medicina da Universidade de São Paulo
(FMUSP). Research Grant: Fundação?de?Amparo?à?Pesquisa?do?Estado?de?
Employment: Faculdade de Medicina da Universidade de São Paulo
Employment: Faculdade de Medicina da Universidade de São Paulo
Employment: Faculdade de Medicina da Universidade de São Paulo
Monica L. Zilberman
Employment: Faculdade de Medicina da Universidade de São Paulo
Ana G Hounie
Employment: Faculdade de Medicina da Universidade de São Paulo
*** Significant: Amounts given to the author’s institution or to a colleague for
research in which the author has participation, not directly to the author.
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