Concept, Diagnostic Criteria and
Classification of Autistic Disorders:
A Proposed New Model
Dr Khalid A Mansour
Concepts of autism and autistic spectrum can be difficult to understand to the public as
well as untrained professionals. This is reflected in difficulties in diagnosing mild autism;
first recognised in adulthood, compared with severe autism; first recognised in
childhood. This paper provides a new model of autistic spectrum disorders that is simple
and easier to use. It is more in line with established literature about autism, clinical
evidence and recent developments in neurosciences. The model has used the Triune
Brain Theory to establish the neuropsychological basis for the Object Related,
Emotional and Social intelligences. The model suggests that autism is a form of “Socio-
Emotional Learning Disability”. Diagnostic criteria include; “core symptoms” that do exist
in both severest as well as mildest forms of autism. Other symptoms are included under
“associated symptoms”, “compensatory symptoms” and “complications related
symptoms”. Autistic spectrum has been classified into Central and Peripheral autism
disorders as well as Non-autistic socio-emotional conditions. The difference between
Central and Peripheral autism depends on severity of symptoms according to a
particular cognitive-clinical scale based on Lezak’s stages of intelligence. In this model
Narcissistic Personality Disorder, is part of the autistic spectrum. Evidence from the
literature has been summarised and discussed.
Keywords: autism, autistic spectrum, asperser syndrome, high functioning autism,
narcissistic personality disorder, Triune Brain Theory.
Declaration of interest: None
Concept, Diagnostic Criteria and Classification of Autistic Disorders:
A Proposed New Approach
The concepts of autism and autistic spectrum disorders (ASD) can difficult to
comprehend especially for people who don’t have first-hand knowledge of autistic
people. It is well known for clinicians who work in the field of developmental
disorders that even experts can disagree about diagnosis of autism, especially the
milder forms of it (1-4). Part of the problem is that the current concepts of autism
and autistic spectrum are not clear enough. They seem to need further
development and clarity (4-5). Another part of the problems is that most of the
literature refer to severe autism in children as the prototype of autistic disorders.
This makes it difficult to apply such literature on milder forms of autism especially
the ones that are first diagnosed in adulthood.
This paper represents the author’s effort to reformulate the concepts of both autism
and autistic spectrum, provide clearer diagnostic criteria and “easier to use”
classification of autism. The model proposed in this paper will expand further on the
main features of the autistic spectrum. This new model would try to explain autism
and autistic spectrum in a more consistent and meaningful way in reference to both
clinical and public use. It would also aim to produce a generic model which is fit to
deal with both mild and severe autism as well as autism-like conditions.
Although this model presents new formulations of autism, it is based on the
literature and clinical observations. This includes both well-established theories of
autism that have been widely accepted by professionals as well as the recent
advances in neuropsychological studies especially Triune Brain Theory of Paul
Historically established data about autistic spectrum disorders:
There have been a number of research data and theories that have been better
received and accepted by clinicians all over the world for a reasonable length of
time. These concepts are used here as landmarks for understanding ASD. These
include Kanner’s concept of Infantile Autism (7), the distinction between autism and
learning disabilities (7), the distinction between autism and childhood
schizophrenia (8-9), the data about milder forms of autism including high
Functioning Autism (HFA) (10), Asperger’s Syndrome (AS) (11-12), Broader Autism
Phenotype (13), Semantic Pragmatic Syndrome (Pragmatic Language Impairment )
(14), autistic spectrum disorder (15), “Theory of Mind” or “empathy” in autism (16),
“Mirror Neurons” (17-18), the work about co-morbidity in autism especially with
Learning Disability, Attention Deficit Hyperactivity Disorder (ADHD) and epilepsy
(19-21), the studies about forensic aspects of autistic spectrum disorders (22-23),
the work about cognitive aspects of autism including the “savant” phenomenon
(10,24), the genetic aspects of autism (25-27), its association with abnormalities in
the brain (10-28), and the different types of social inadequacy in autism (15).
Perhaps the diagnostic criteria of autistic disorders in the “Diagnostic and Statistical
Manual of Mental Disorders, Fourth Edition” (DSM-IV) (29) and “International
Statistical Classification of Diseases and Related Health Problems, 10th Revision”
(ICD-10) (30) are the most recognised embodiment of the concept of autism.
However there have been many difficulties which yet have to be dealt within those
two systems (31).
1) The DSM-IV and ICD-10 diagnostic classification of autistic disorders are
categorical rather than dimensional classifications under the heading of
Pervasive Developmental Disorders. The categories of Pervasive
Developmental Disorders include syndromes like Rett’s Syndrome and
Childhood Disintegrative Disorders. These disorders are of doubtful
significance from classification point of view. The use of such strict diagnostic
criteria has lead to inevitable over use of the category “Pervasive
Developmental Disorder Not Otherwise Specified” (32). However this is
expected to be corrected in DSM-V and ICD-11 (33).
2) The diagnostic criteria of autism are still focused on childhood severe autism
with less emphasis on milder forms of autism (34) that could be diagnosed for
the first time in adulthood.
3) The classifications do not include important concepts like “High Functioning
Autism” (HFA). This is probably partially due to the ambiguity of the difference
between HFA and Asperger’s Syndrome (AS) (35).
4) The diagnostic criteria are heavily influenced by the usual “diagnostic triads”
like the one developed by Lorna Wing (15) at the expense of other features of
autism like the “lack of empathy” and “lack of theory of mind” (36-37).
The Triune Brain Theory:
The Triune Brain is a model of brain functional structures based on evolutional
analysis of comparative neuroanatomy of vertebrates. The model has been
proposed by the American neuroscientist Paul D. MacLean in his book “The Triune
Brain in Evolution. Role in Paleocerebral Functions” (6). According to Maclean, the
human brain is made of three integrated but specialised brains;
1) The Reptilian Complex: (brain stem, cerebellum and basal ganglia), which is
the main brain structure in reptiles and fish. This part of the brain is
responsible for instinctual behaviours involved in exploration, feeding,
dominance, aggression, territoriality, procreation and behavioural motor
routines; aiming at achieving self-preservation and procreation.
2) The Limbic System: composed mainly of the septum, amygdala,
diencephalon, hippocampus complex and cingulate cortex. When the Limbic
System is added to the Reptilian Complex (as in the brains of lower mammals
like rats, cats and dogs), it starts to produce functions like; bonding, nursing,
parental care, separation anxiety, audio-vocal communication and
playfulness; aiming at maintaining mother–offspring contact.
3) The Neocortex: a structure found uniquely in higher mammals like apes and
humans, when its functions are added to the Limbic System and the Reptilian
Complex, this produces new skills like social languages, abstraction, planning,
and perception; aiming at preservation of ideas and transmission of culture
from generation to generation.
This theory is indirectly supported by the clinically established observations about
the human brain development. It is known that, phylogenetically, older brain areas
mature earlier in humans than newer ones. This means that reptilian brain in
humans matures earlier than the limbic lobe and then the Neocortex. This is
consistent with MacLean’s theory (38). The developmental milestones in humans
indicate that the functions of the Reptilian Complex, Limbic System and Neocortical
functions follow different lines of maturity. Babies in the first year to two rely mainly
on their Reptilian structures to produce their main functions like homeostasis and
identifying objects and producing primary sensori-motor development. In the years
3-5 children seem to develop emotional functions when the Limbic System starts to
be more functional. Later social skills start to develop further in school stages and
after that in a way consistence with what we know about neocortical maturity in the
human brain (39).
It is also possible to view regression in major mental illness to be consistent with
Maclean’s theory too. In major brain disease like dementia, schizophrenia or
demyelinating diseases, skills attributed to neocortex, are more likely to be lost
before those of the limbic lobe and then those of the reptilian complex in some
form of succession indicative of uniqueness and independence of these brain
Table 1: Socio-emotional line of brain development and regression:
5 y and above
Facilitated mainly by
neocortex (frontal lobe)
2 – 5 y
Facilitated mainly by
0 - 2 y
Facilitated mainly by
Based on Maclean theory, it is possible to think of the human brain functioning as
is the final product of integration of three subsystems. One brain subsystem is
more specialised in processing object related data. Another subsystem is more
specialised in processing emotional data. The third subsystem is more specialised
in processing social data. Subsequently, it is possible to subdivide human
intelligence into three different components; Object Related Intelligence, Emotional
Intelligence and Social Intelligence.
In this model, intelligence is defined as in the main stream psychology (e.g. the one
by the “Mainstream Science on Intelligence”) (40). It is also consistent with
Spearman’s G factor or general intelligence (41). This means that it is a stable skill
hardly affected by age, education or training. However, it is separated into three
main domains; the object, the person and the group.
The idea that there could be Emotional and Social Intelligences separate from the
object related intelligences (usually represented by IQ), is not a new idea in
neurosciences or psychiatry. It is widely accepted among clinicians and neuro-
researchers that that emotional intelligence (42-44) and social intelligence (45-46)
could exist independently from general intelligence.
Functions of the three intelligences:
The main function of intelligence is survival or effective management of the
environment. While this is relatively clear regarding materialistic or Objects Related
Intelligence, it needs further analysis with Emotional and Social Intelligences.
Social Intelligence is meant to be the skills necessary to function in a group to
achieve a shared goal even if there is no emotional attachment with members of
the group. Here the group is the primary functioning unit and not the individual and
the goal is larger than what could be achieved by each individual separately. It is
the intelligence necessary for creating societies and civilisations. Social intelligence
is usually practiced in the wider society like in the streets, public transport, new
work places, etc. In this regard, the above stages of social intelligence materialises
itself in the form of social appropriateness, social cooperation and promoting group
Emotional intelligence is simply the ability to understand and manage emotional
data to achieve better survival. There could be central psychological mechanisms
that explain how it works.
1) “Theory of Mind” seems to be central to emotional intelligence.
2) Theory of Mind in turn leads to “Empathy”, when applied to others (10),
and to “Insight”, when applied to one self (47).
3) Empathy then leads to the ability to “Individualise” people i.e. perceiving
each individual as unique and not just a member of a group. Then an
emotional charge is attached to the individual. If this emotional charge is
positive, the individual becomes intimate person too like; siblings, partners,
friends, relations, etc.
4) Insight can also lead to self awareness, self criticism, remorse after
making mistakes and joy after doing well.
5) Empathy and insight then allow the development of mutually convenient
and mutually beneficial relationship with other individuals. This in turn
achieves the ultimate goal of acquiring the “intimate, supportive
relationships” most crucial for survival in humans.
6) Other components in the limbic system functioning constitute the
machinery that serve the above system. They include abilities like “face
recognition”, mirror neurones, amygdala labelling systems, hippocampus
emotional memory functions, etc.
The possession of such intelligences can dramatically enhance survival skills and
levels of functioning in humans. Object Related Intelligence is the simpler form of
intelligence and is shared (in one level or another) with most animals. Adding the
emotional brain dimension improves the Object Related Intelligence and allows
new abilities to emerge like “partnerships” and “establishing families” which is a
major advance above the previous level. The Social Intelligences allows
enhancement of Object related and Emotional Intelligences but also adds
enormous new functions including building societies and civilisations. This would
be the peak of human performance that is not shared with any other animals.
Diagram 1: Relationship between functioning and levels of integration:
Clinical components of intelligences:
In this model, the clinical concept of intelligence is further subdivided into neuro-
behavioural components consistent with Lezak four classes of intelligence/cognition
(48); “receptive functions”, “memory and learning”, “thinking” and “expressive
functions”. However they have been modified to suit clinical usage as explained in
clinical stages of intelligence or skills compared to “Lezak’s classes of
1- Monitoring the data (Object related,
emotional or social),
2- Understanding/analysing the data
3- Formulating an increasingly appropriate
response to the data
4- Memorising the data and learning new ways
to improve responses by learning from one’s
own mistakes or by observing others
5- Generalising the new skills and applying
them in new/unfamiliar situations by the use
of imagination (episodic future thinking /
6- Mastering the new skills via training so that
they can be used in stressful situations
without pathological coping mechanisms like
“hostile dependence”, somatisation or
Expressive Functions - I
Memory and Learning
Expressive Functions - II
Usefulness of tri-dimensional intelligence to explain other clinical
Building on the idea that the triune brain could possess tri-dimensional intelligence,
it is possible to see the link between this model and personality disorders as
explain in the following illustrations.
Intelligence” (IQ), “Emotional Intelligence” and “Social Intelligences”:
An average person should possess functional “Object Related
Emotional Intelligence Social Intelligence
Intelligence” and normal “Social Intelligence” would be identified as some one with
learning difficulties but with good coping abilities due to his other intelligences are
A person with low “Object Related Intelligence” but normal “Emotional
Emotional IntelligenceSocial Intelligence
Intelligence” but low “Emotional Intelligence” could suffering from antisocial
A person with normal “Object Related Intelligence” and normal “Social
Emotional Intelligence Social
Intelligence” but low “Social Intelligence” could be having schizoid personality (high
self-satisfaction) or avoidant personality (low self-satisfaction):
A person with normal “Object Related Intelligence” and normal “Emotional
Intelligence” but normal “Emotional Intelligence” could be seen as someone with
both learning disability and social awkwardness but still able to bond with carers:
A person with low “Object Related Intelligence” and low “Social
Intelligence” but functional “Social Intelligence” could be seen as someone with
both learning disability problems due to difficulties in bonding with carers:
A person with low “Object Related Intelligence” and low “Emotional
Learning Disability with
(Learning Disability with
Diagnostic Criteria of Autism and
Autism as a socio-emotional Learning Disability:
This model adopts the view that autism is primarily a “socio-emotional learning
disability” and that the social and emotional dimensions are equally central for
diagnosis of autism. This model suggests that autism is better seen as a
biologically determined impairment in both emotional and social intelligences with
subsequent; “pervasive”, “regressive” and “developmental (since childhood)” socio-
“Social Intelligence” (with functional “Object Related Intelligence” in this table):
Autistic Spectrum Disorder
A person with autism essentially has low “Emotional Intelligence” and low
Intelligence” and low “Social Intelligences”. This would be autism with learning
A person with low “Object Related Intelligence”, low “Emotional
Learning Disability with
Autistic Spectrum Disorder
X X X
Core symptoms of autism and the emotional dimension:
In this model, core symptoms of autism are those symptoms that are shared
between both most severe and most mild autism. This would then exclude low IQ,
severe communication disorder, marked stereotyped behaviour, avoiding eye to
eye contact, pica, rocking, regressive obsessive compulsive disorder, etc. Such
model is not in total agreement with the DSM-IV and ICD-10, criteria of core
autistic features. In DSM-IV and ICD-10 core features of autism do not identify the
emotional dimension as an independent or major dimension separate from the
The emotional dimension in Autism has been mentioned implicitly inside the
“qualitative impairment in social interaction” section in DSM-IV and ICD-10 (29-30).
Then two vaguely worded emotional features were mentioned among four criteria;
“lack of social or emotional reciprocity” and “failure to develop peer relationships”.
Even then they are not crucial to make the diagnosis.
This model suggests that “qualitative impairment in emotional interactions” is as
important and as influential as the “qualitative impairment in social interactions” in
diagnosis of autism. The evidences in favour of a more elaborate emotional
dimension are numerous (49).
1) There is now significant level of agreement that emotional processing
problems like; lack of empathy, poor self-awareness, self-centredness, poor
reciprocation of emotion, poor ability to maintain emotional relationships,
anxiety and anger outbursts are more or less central features of autism (10,
2) Social and emotional skills are largely independent neurobiological functions
of the brain. While Social Intelligence is mainly centred in the neocortex
especially the frontal lobe, emotional skills are mainly related to the limbic
3) There are plenty of research data indicative of a high association between
autism and abnormalities in limbic system (52-54) as well as the studies about
the mirror neurones (18).
4) Neuropsychological research testing of emotional functioning (e.g. theory of
mind, empathy, facial recognition, etc) also suggests that impairment in
emotional functioning is central feature in autism (10,55).
5) Emotional development seems to be primary to social development (49).
Emotional functioning starts earlier in human development to social
functioning both developmentally and from evolutionary point of view. To be
able to deal with social groups and maintain reasonable social functioning we
need a minimum degree of self-awareness and empathy.
Other features of autism:
In this model, other features in autism have been divided into three groups of
symptoms; “compensatory behavioural symptoms”, “associated symptoms” and
1) Compensatory behavioural symptoms: like dependence on others, restricted
life style, having islets of interest, rigid routines, etc.
2) Associated symptoms: these seem to be associated disorders probably
caused by the same pathology causing autism. they include learning
disability, attention deficit hyperactivity disorder (ADHD), epilepsy, involuntary
movement disorders, pica, rocking, obsessional symptoms, ritualistic
symptoms, sensory processing disorder, etc. All these features can exist
independently of autism. Any single associated symptoms, alone, does not
justify a diagnosis of autism but can increase the likelihood of the diagnosis
once the core symptoms are first identified.
3) Complications: like “Habit Disorders” that can be seen as learnt pathological
behaviour related to coping with stress e.g. fire setting, misuse of
psychoactive substances, regressive aggression towards carers,
dysfunctional sexual habits, etc.
In this model communication disorder is paramount but it is divided into social and
emotional communication problems. They are included into the social and
emotional impairment sections.
In this model, “repetitive and stereotyped behaviours” (RSB), is not put separately
as it does not exist in all forms of autism (56). RSB was put as a possible feature in
“pervasive developmental disorder not otherwise specified” in the DSM-IV (29). In
this paper’s model, part of the stereotyped behaviour would be a compensatory
coping strategy e.g. keeping rigid routine to avoid losing control on the
environment. Another part of it is obsessional, ritualistic or involuntary motor
movement and this would be included under associated symptoms (57).
Differential diagnosis: Emotional and social skills can be seriously dysfunctional
in many psychiatric disorders and not all autistic or even biological in nature.
Acquired socio-emotional deterioration e.g. in chronic schizophrenia and
dementia. Premorbid functioning is usually relatively high if not normal compared to
Socio-emotional problems since childhood in individuals who are
developmentally normal in terms of social and emotional brain centres:
1) This could include complicated cases of; Learning Disability, Attention Deficit
Hyperactivity Disorder (ADHD), Post Traumatic Stress Disorder (PTSD),
physical disability with poor coping, severe neglect, severe isolation, severe
deprivation, complicated immature personalities or complicated personality
disorders etc. Complicating matters here include mental or physical traumas,
mental or physical illnesses, ADHD, misuse of psychoactive substances, etc.
2) In such cases it usually possible to see some quantitative and qualitative
differences in symptoms. The socio-emotional difficulties do not exist in all
areas of functioning of the affected individual e.g. symptoms are prominent at
home but not in school.
Diagnostic Criteria of Autistic Spectrum Disorders:
(I), (II) and (III) need to apply on the patient’s presentation:
(I) A diagnosis of autistic spectrum disorder must include features of both A,B,C and
possible features of D and E. The more symptoms, the severer the condition on the
a. Impairment of the development of Emotional Intelligence with impaired
emotional functioning that is pervasive, regressive
i.Cross-sectional (from interview and/or observation).
1. Emotional Inattention: poor monitoring of emotional data
2. Emotional Agnosia (alexithymia): poor understanding of
3. Emotional Inadequacy / awkwardness: poor ability to formulate
appropriate emotional responses.
4. Emotional dysmimia: poor ability to learn appropriate emotional
responses from others.
5. Emotional Concreteness: poor ability to apply previously learnt
emotional skills in new or unfamiliar situations.
6. Emotional Vulnerability: poor ability to apply newly learnt
emotional skills in stressful situations. Instead exhibits emotions like
a. Hostile dependence: hostility used as a mean to facilitate
dependence in safe relationships e.g. parents or carers
b. Anger outbursts: e.g. “catastrophic reactions” to stress
c. Quick superficial despair
d. Somatisation / hypochondriasis
and since childhood :
ii.Longitudinal (from history):
1. Self-centeredness; inappropriate to developmental level and
2. Poor self-awareness, poor ability to develop remorse or learn from
3. Poor empathy or appreciation of others feelings
4. Poor ability to reciprocate emotions.
5. Hostile dependency on safe relations.
6. Failure to develop emotional relationships appropriate to
developmental level and social norms
7. Treating people as objects or preferring objects over them
iii.Impairment of Emotional Communication.
1. Lack of emotional communication (e.g. poor appreciation of
emotional communication by others and poor ability to emotionalise
his/her communication in response).
2. Immature/childish emotional communication (e.g.