Comorbidity: ASD & Mental Health

What is comorbidity?

In psychology terms, comorbidity simply refers to the presence of more than one disorder that exists alongside a primary diagnosis.

Although there are many physical conditions, and other neurodevelopmental conditions, that are comorbid with ASD (e.g. ADHD, developmental coordination disorder, gastrointestinal symptoms, sensory problems, sleep disorders, epilepsy, intellectual disability etc.) this article focuses specifically on the co-occurrence of mental health conditions. The statistics for comorbidity rates in ASD vary, perhaps due to the nature of studies, but it is said that nearly three-quarters of children with ASD also have another medical or psychological condition.
 

Common ASD and mental health comorbidities

With some primary diagnoses, such as Autism Spectrum Disorder (ASD), we often find that symptoms of another/other psychological disorders co-occur and, if they meet the DSM-5 criteria, should be diagnosed in order to fully explain the symptoms that the individual is experiencing. In some circumstances, however, disorders such as Social Anxiety Disorder are not commonly diagnosed in people with ASD because such symptoms are better explained by the ASD itself.

ASD & phobia

Anxiety as a whole is common in individuals with ASD but specific fears and phobias is one of the most frequent subtypes, with common phobias being loud noises, dogs, spiders, sleeping alone, going to the doctors etc. One explanation for this could be due to their black and white thinking (i.e. thinking in extremes) and thoughts such as, "this dog is definitely going to kill me" occur rather than logical thinking and realising that a dog attack on a human is very rare. The fear of loud noises, in particular, might somewhat stem from heightened sensitivity to loud noises in general.

One of the key therapeutic mechanisms in evidence-based treatments for specific phobias and fears is graduated exposure, however, this type of treatment may require adaptation when using it to treat individuals with ASD. This is because graduated exposure often begins with imagining the feared object and becoming desensitised to that, initially. For individuals with ASD, the act of imagining certain situations can be difficult and this has been found in both children and adults.

ASD & OCD

ASD and OCD are two different conditions, although some symptoms of autism overlap with OCD and can look similar; for example, people with ASD and people with OCD may display repetitive and obsessive behaviours, such as lining up toy cars. A key difference between the two is the purpose or motivation for the behaviour. For example, it is said that if you were to try and stop the repetitive routine of an individual with autism, he/she will not show distress and you may be able to redirect his/her attention with a new object. With OCD, the repetitive behaviours of an individual are related to deep fears and if you were to try and stop their routine, they could become extremely distressed.

ASD & anxiety

It is said that up to 84% of people with ASD also have anxiety symptoms. There are many subtypes of anxiety but some particularly common forms include OCD (as above), separation anxiety disorder (in children), phobia (as above) and social anxiety disorder. There are some possible reasons as to why individuals with ASD are particularly prone to anxiety:

• Coping with change: individuals with ASD can be affected by the smallest of changes to their daily routine and structure. Anything that is marginally different from their usual routine can cause anxiety.
• Sensory needs: there are many circumstances in which a person with ASD can feel overwhelmed and anxious such as crowded places, places with loud noises, different smells etc.
• Thinking in extremes: we often describe ourselves as "over-thinkers" and "worriers" but, to some extent, we are able to talk ourselves out of thinking about the worst possible outcome because we know that this would be extremely unlikely to happen. Many individuals with ASD are unable to talk themselves out of thinking in extremities and can become extremely anxious when fearing that the worst is going to happen. As well as this, they can also misinterpret something that was seen, said or done in the past.

ASD & depression

Depression is common among individuals with higher-functioning ASD and during adolescence as they are more able to understand and notice their difficulties, but, because some individuals with ASD have difficulty labelling their feelings, it can be particularly hard for them to communicate symptoms. Because of this, it is more common for the parent/caregiver to identify symptoms of depression in individuals with ASD through observable behaviours, such as; more frequent or more repetitive or compulsive behaviour, tantrums or aggressive behaviour, agitation, increased sadness, tearfulness, an increasingly negative affect, sleep and weight disturbances, starting to hurt themselves or hurting themselves more often (e.g. hand-biting), finding it harder to do everyday things be obsessed with death or talking about suicide or harming themselves. 
 

Comprehensive neurodevelopmental assessments

Even though mental health can be a common problem for people with ASD, it can often be overlooked due to a one-dimensional approach of looking at neurodevelopmental disorders. Any assessor needs to take account of the prevalence of comorbidity in neurodevelopmental disorders is high and so offer a comprehensive neurodevelopmental disorder assessment which looks at the full range of issues, including mental health.

At the post-diagnosis and treatment stage, it is important that any therapist working on treating anxiety in individuals with ASD also have an understanding of ASD as this can affect how well the therapy works. Some therapies such as graduated exposure, may need to be adapted.