ASD: diagnostic criteria

April 4, 2020 0 By S Harachand

The Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 groups autism and Asperger syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS) and childhood disintegrative disorder under one umbrella term — autism spectrum disorder (ASD).

The DSM description of ASD diagnosis involves the severity of social communication symptoms, the severity of fixated or restricted behaviours and hyper or hyposensitivity to sensory stimuli. The manual has also relaxed the onset from 3 years of age to “early developmental period”.

Published by the American Psychiatric Association (APA), DSM is a diagnostic system widely used by the clinicians, researchers, and policy makers in the US.

DSM-5 published in 2013 notes that autism spectrum disorder is characterised by:  

A. Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history:  

1. Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions. 

2. Deficits in nonverbal communicative behaviours used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication. 

3. Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behaviour to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to the absence of interest in peers. 

B. Restricted, repetitive patterns of behaviour, interests, or activities, as manifested by at least two of the following, currently or by history: 

1. Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases). 

2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behaviour (eg, extreme distress at small changes, difficulties with transitions, rigid thinking
patterns, greeting rituals, need to take the same route or eat food every day). 

3. Highly restricted, fixated interests that are abnormal in intensity or focus (eg, strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest). 

4. Hyper or hyporeactivity to sensory input or unusual interests in sensory aspects of the environment (eg, apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement). 

C. Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities or may be masked by learned strategies in later life). 

D. Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning. 

E. These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and an autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.”

ICD

The International Classification of Diseases (ICD) produced by the World Health Organization (WHO) is an alternate classification publication. 

The 11th edition of the ICD, which is due for publication in 2022, notes that:

“Autism spectrum disorder is characterized by persistent deficits in the ability to initiate and to sustain reciprocal social interaction and social communication, and by a range of restricted, repetitive, and inflexible patterns of behaviour and interests. 

The onset of the disorder occurs during the developmental period, typically in early childhood, but symptoms may not become fully manifest until later, when social demands exceed limited capacities.

Deficits are sufficiently severe to cause impairment in personal, family, social, educational, occupational or other important areas of functioning and are usually a pervasive feature of the individual’s functioning observable in all settings, although they may vary according to social, educational, or other context. 

Individuals along the spectrum exhibit a full range of intellectual functioning and language abilities.”

There are several subtypes of autism spectrum disorder:

1. ASD without disorder of intellectual development and with mild or no impairment of functional language. 

All definitional requirements for autism spectrum disorder are met, intellectual functioning and adaptive behaviour are found to be at least within the average range (approximately greater than the 2.3rd percentile), and there is only mild or no impairment in the individual’s capacity to use functional language (spoken or signed) for instrumental purposes, such as to express personal needs and desires.

2.1 ASD with the disorder of intellectual development and with mild or no impairment of functional language. 

All definitional requirements for both autism spectrum disorder and disorder of intellectual development are met and there is only mild or no impairment in the individual’s capacity to use functional language (spoken or signed) for instrumental purposes, such as to express personal needs and desires.

2.2 ASD without disorder of intellectual development and with an impaired functional language. 

All definitional requirements for autism spectrum disorder are met, intellectual functioning and adaptive behaviour are found to be at least within the average range (approximately greater than the 2.3rd percentile), and there is marked impairment in a functional language (spoken or signed) relative to the individual’s age, with the individual not able to use more than single words or simple phrases for instrumental purposes, such as to express personal needs and desires. 

2.3 ASD with the disorder of intellectual development and with impaired functional language. All definitional requirements for both autism spectrum disorder and disorder of intellectual development are met and there is marked impairment in functional language (spoken or signed) relative to the individual’s age, with the individual not able to use more than single words or simple phrases for instrumental purposes, such as to express personal needs and desires.  

2.4 ASD without disorder of intellectual development and with the absence of functional language. 

All definitional requirements for autism spectrum disorder are met, intellectual functioning and adaptive behaviour are found to be at least within the average range (approximately greater than the 2.3rd percentile), and there is complete, or almost complete, absence of ability relative to the individual’s age to use functional language (spoken or signed) for instrumental purposes, such as to express personal needs and desires. 

2.5 ASD with the disorder of intellectual development and with absence of functional language. 

All definitional requirements for both autism spectrum disorder and disorder of intellectual development are met and there is complete, or almost complete, absence of ability relative to the individual’s age to use functional language (spoken or signed) for instrumental purposes, such as to express personal needs and desires.”