Medical Diagnostic Criteria for Neurodevelopmental Disorders

There are internationally agreed criteria for diagnosing neurodevelopmental disorders¹ . These criteria are reviewed and updated at periodic  intervals.  Changes are generally based on substantive research evidence. 

I have summarised the main components of these criteria for Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder in the sections below. 

Professionals use a range of tests to assess for neurodevelopmental disorders. There is currently no single individual test which will provide a diagnosis for either condition. 

Autism Spectrum Disorder

The current term ‘Autism Spectrum Disorder (ASD)’ brings together a wider number of diagnoses which formerly included Autism Disorder, Asperger’s Syndrome, High Functioning Autism, Pervasive Developmental Disorder (not otherwise specified).

The two key determinants of ASD are :

1)    Persistent deficits in social communication and social interaction across multiple contexts

and

2)    Restricted, repetitive patterns of behavior, interests, or activities.

To meet the criteria for a diagnosis, an individual needs to present with difficulties which started in their early years but may not have become fully apparent until they reach a stage where social demands exceed their ability. Their difficulties with the ‘triad’ of social communication, interaction and restricted interests, must cause a significant impact on social, academic, work, or other areas of functioning.

The assessing professionals need to :

·         rule out alternative diagnoses, such as Social (pragmatic) Communication disorder

·         determine whether difficulties may be better explained by an intellectual developmental disorder or global developmental delay. It is possible to have ASD and an intellectual disability.

Difficulties in day-to-day life:

It is important to note that individuals with Autism can present with other difficulties including sensory, executive functions, emotions, motor skills, and physical health issues. The research evidence is just not strong enough to have them included formal medical diagnostic criteria at this time. These wider functional difficulties vary from individual to individual, but they can also have a significant impact on day-to-day functioning. That’s why it’s important to build a ‘personal picture’ of the strengths and challenges for each child.

The severity of the condition varies. Strengths and challenges can change over time.

Attention Deficit Hyperactivity Disorder

There are three different types (or presentations) of ADHD. These are ‘inattentive’, ‘hyperactive-impulsive’, or a ‘combined’ type.

Key determinants of ADHD are grouped into 2 categories which help determine the type of ADHD.

1)    Determinants of Inattention

These descriptors are a summary of the symptoms taken into account during a diagnostic assessment:

-          doesn’t pay close attention to details or makes careless mistakes

-          difficulty sustaining attention in tasks or play activities

-          doesn’t seem to listen

-          doesn’t follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace

-          difficulty organizing tasks and activities

-          avoids, dislikes, or is reluctant to engage in tasks requiring sustained mental effort

-          loses things needed for tasks or activities

-          easily distracted by things in the environment or own thoughts

-          forgetful in daily activities

For diagnosis to be made of ‘inattentive type’, children require 6 or more symptoms, those aged 17+ years require 5 or more symptoms, in each of the key determinants above.

2)    Determinants of Hyperactivity and Impulsivity

These descriptors are a summary of the symptoms of Hyperactivity taken into account during a diagnostic assessment:

-          fidgets, taps hands or feet, squirms in seat

-          leaves seat in situations when remaining seated is expected

-          runs or climbs in situations where it is inappropriate

-          unable to play or take part in leisure activities quietly

-          “on the go” acting as if “driven by a motor”

-          talks excessively.

These descriptors are a summary of the symptoms of Impulsivity taken into account during a diagnostic assessment:

-          blurts out an answer before a question has been completed

-          trouble waiting his / her turn

-          interrupts or intrudes on others

For diagnosis to be made of ‘hyperactive-impulsive’ type’, children require 6 or more symptoms, those aged 17+ years require 5 or more symptoms, in each of the key determinants above.

To meet the criteria for a diagnosis, an individual needs to present with a persistent pattern of difficulties which have been present for at least 6 months. Some symptoms need to have been present before 12 years of age. Symptoms need to be present in two or more settings.

The difficulties must be to a degree that they interfere with, or reduce the quality of, social, academic, work, or other areas of functioning or development.

The assessing professionals need to :

·         rule out alternative diagnoses, such as psychotic disorder, mood disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication or withdrawal

·         determine whether difficulties may be better explained by oppositional behaviour, defiance, or failure to understand tasks or instructions

Difficulties in day-to-day life:

The severity of the condition can vary and this can determine the degree of impact on everyday functioning.

Reference

1. American Psychiatric Association (2022) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR)

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