Autism Spectrum DisorderSymptoms

Autism Symptoms and Diagnosis #

Autism spectrum disorder (ASD) is defined (and diagnosed) based on a collection of symptoms. The type and severity of symptoms that are used to diagnose autism have changed over time. ASD symptoms generally include problems with social interactions, paired with certain types of behavioral patterns, such as strong adherence to routines, repetitive behaviors, or abnormally strong and fixed interests. Many people with ASD have co-occurring mental and physical health disorders, some of which have symptoms that overlap with autism.

Autism Diagnosis #

Currently, clinicians in the United States use the criteria listed in a guidance document called the Diagnostic and Statistical Manual, fifth edition (DSM-5); clinicians elsewhere might use the International Classification of Diseases, version 11 (ICD-11).¹ While there are some similarities between the DSM-5 and ICD-11 definitions of ASD, their diagnostic criteria are not the same. For example, a child diagnosed with autism under the ICD-11 may not necessarily be diagnosed with the condition under DSM-5, and vice versa. NeuroCytonix relies on the DSM-5 criteria for clinical studies of autism.

The first stage of diagnosis often involves a screening. These screenings can be given by a teacher, social worker, or other professional familiar with autism symptoms. While the screening generally isn’t used to make a formal diagnosis, it will identify children who might be at risk of autism.

Formal autism diagnoses are based on an evaluation of a child’s behavior. A clinician (such as a psychologist) will assess whether the child’s symptoms align with the domains listed in the DSM-5. In general, the symptoms must have arisen early in childhood, although more recently clinicians have begun diagnosing autism even in those whose symptoms did not begin until later in development. Clinicians use defined scales to determine whether a child’s behavior falls within the normal range for their age and stage of development. 

In addition to making a diagnosis, clinicians will generally also estimate a level of severity.² Level 1 indicates that a child needs some support, level 2 indicates the child needs significant support, while level 3 indicates the child needs the highest level of support for daily function.

Diagnostic Criteria for Autism (DSM-5) #

Autism diagnosis depends on symptoms in two distinct areas: social communication and behavior.^1-4 To receive an ASD diagnosis, a child must have problems in all the social communication domains and in several behavioral domains; children with symptoms in fewer domains might have “autism-like traits,” but will not receive an autism diagnosis.

There are three core areas of social interaction that clinicians consider. A child must have difficulty in all three areas.

• Social Reciprocity: Children with autism often struggle to approach people that they want to talk with, or may have difficulty maintaining a smooth conversation.
• Non-verbal Communication: Children with autism may have trouble understanding gestures or other body language. They also may not engage in eye contact or look at people’s faces.
• Relationships: As children develop, they generally learn to behave differently in different contexts. For example, a child may be respectful with a teacher but playful with a friend. Children with autism might struggle to understand the differences between different relationships or switch behavioral modes, leading to inappropriate behaviors in certain contexts. They also have trouble making and keeping friends.

Children with autism also have unusual behaviors. In order to receive an autism diagnosis, a child must display symptoms in two of four behavioral areas.

• Motor movements: Children with autism might do the same activity over and over again over long periods of time (repetitive motor movements), or they might only do certain types of movements (restricted behavior). Examples of repetitive behaviors include lining up or ordering toys, or saying the same thing over and over.
• Routines: Many people with autism depend on strict routines, and even small adjustments to their routine can be distressing. They might also be very rigid in their thinking, requiring tasks to be managed in one particular way.
• Interests: Children with autism often display abnormally strong interest in a single subject, and maintain that interest over a long period of time.
• Sensory inputs: Children with autism may react abnormally to light, sound, textures, or pain. Some children may be over-sensitive, while others might be under-responsive. 

Other Autism Symptoms #

In addition to difficulties with social interaction and behavior, children with autism often have other symptoms. These can include:

• Sleep disturbances or insomnia^5,6
• Restricted or rigid food choices⁷
• Gastrointestinal symptoms^8,9
• Obesity⁸

Conditions that Co-occur with Autism #

As many as 70% of people with autism also have other co-occurring conditions, especially mental health disorders.⁸ For example, 28% of people with ASD also have attention deficit hyperactivity disorder (ADHD); problems with executive and social function associated with ADHD can overlap with ASD symptoms. Anxiety, depression, obsessive/compulsive disorder (OCD), irritability, and aggression are also common in people with autism. 

While the presentation of ASD varies widely, a significant proportion (upwards of 15%) of people with autism also have an intellectual disability, and many have speech and language delays. Epilepsy, cerebral palsy, and other neurological disorders are also much more common in people with autism than in the general population.¹⁰

Examples of Measurement Scales for Autism #

There are a wide variety of scales that have been developed to screen or test for autism.¹¹ Some of these are based on a questionnaire given to parents or a teacher, while others require a long interactive session between a clinician and the child. A few examples are listed below.

Scales used to assist diagnosis:

• Autism Diagnostic Observation Schedule 2 (ADOS-2): a clinical observation-based exam, the ADOS-2 includes a variety of activities and tasks that demonstrate a child’s abilities and function within autism domains. Versions are available for children 12 months and older.^12-14
• Childhood Autism Rating Scale (CARS): clinician-reported scale based on observation of the child, or optionally through a parent’s questionnaire, designed for young children and those with intellectual disability. Standard form is used for children under age 6 or those with IQ less than 80; “High Functioning” form under CARS-2 is used for those over age 6 with IQ 80 or above.¹⁵
• Gilliam Autism Rating Scale (GARS): a clinician, parent, or teacher-reported scale that assesses each of the DSM-5 defined behavioral and communication domains. However, this scale has been reported to have lower reliability than some other options.¹⁶
• Autism Diagnostic Interview-Revised (ADI-R): a standardized interview given to caregivers, used most often in clinical research.¹⁷
• Adaptive Behavior Assessment System (ABAS): a general assessment that can be used at any age, the ABAS identifies challenges with communication, academics, safety, and other functions of daily life. This scale is not specific for autism.¹⁸

Scales used for screening:

• Modified Checklist of Autism in Toddlers (M-CHAT): a two-stage report that relies on parent-reported symptoms. Used for children between 16 and 30 months of age.¹⁹
• Screening Tool for Autism in Toddlers and Young Children (STAT): an interactive scale administered by a clinician that assesses social and behavioral domains. Useful between 24 and 36 months of age.²⁰

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