Autism spectrum disorder: psychiatric comorbidities

Hello. This talk is going to be on the topic of autism spectrum disorders, with a specific focus on psychiatric comorbidities. My name is Dr. Gerrit van Schalkwyk. I'm the unit chief of the adolescent unit at Butler Hospital and an assistant professor of Psychiatry and Human Behavior at the Alpert Medical School of Brown University.

In this presentation, I'm going to start by talking about some of the conceptual issues that are critical to consider when we talk about the question of a comorbid diagnosis in autism spectrum disorder. Specifically, an issue that we'll get into is: when does one consider an additional set of symptoms as indicating a comorbid diagnosis, versus a symptom dimension that although not called the disorder is in fact part of the disorder, rather than indicating an additional diagnosis? We will then look at specific examples of symptom dimensions that occur commonly in individuals with autism disorder. These include anxiety symptoms, OCD symptoms, psychotic symptoms, and questions related to gender identity. In each case, we'll talk about how best to conceptualize these symptoms, but we'll also talk about the clinical implications of how we choose to do so.

Before we can think about the question of how to make sense of comorbid symptom dimensions in autism spectrum disorder, it's important that we take a little time to think about what the core nature of autism is. This on its own is a complex topic and well beyond the scope of today's presentation, but we'll make a couple of points around this to help us answer the question at hand. Autism spectrum disorders may be described by their core symptom dimension of abnormalities in social functioning. Individuals with autism struggle to encode social information; in other words, to match the expression on their faces, their use of gestures, the tone in their voice, to fully communicate what they mean to. They also struggle to decode social information; in other words, to make sense of the social cues of others, and other subtleties in social communication. Individuals with autism spectrum disorder may have difficulty learning from social environments. Yet, although this is the cardinal symptom of autism, many other symptom dimensions are possible, and many other impairments can be detected. For example, some individuals with autism spectrum disorder may have global cognitive impairment. Individuals with autism may have developmental impairments related to things like identity formation. They may also have developmental impairments around psychosocial functioning. As such, although the cardinal and defining symptom of autism relates to impairments in social functioning, it's the case that many individuals with autism have broader developmental impairments. How do we make sense of this? Many of the cognitive neuroscience explanations of autism (including more prominent recent ideas like predictive coding accounts of autism), describe brain-based deficits that are not specific to social functioning, but rather, argue that individuals with autism have brains that are distinct in how they handle and update expectations, based on novel information in the environment. For example, in social settings, it's important to be able to efficiently attend to important information and ignore unimportant information when many people are speaking at the same time, when people are making a range of gestures and facial expressions in rapid succession. It's difficult, inefficient, and sometimes impossible to try and understand all of what's going on and to pay it equal attention and consider it all to be salient and important. As such, in social situations, it's important that we decide what information to pay attention to and what information we can safely ignore, as it doesn't have significant meaning for either the current situation or for helping us make sense of future situations. Having difficulty in this regard can make it particularly difficult to navigate social situations. Critically, if we situate the deficit not at the level of a social part of the brain specifically, but a more basic difficulty with how we handle novel information, we can expect that people are going to have more than just difficulties in social settings, rather they will have difficulties in any setting where there is complex/an excessive amount of novel information. How does this manifest clinically? Again, the core symptoms of autism include social impairments and restricted interests, as well as repetitive behaviors. However, we may expect that given the basic nature of the brain-based difference that underlies autism, people may have difficulties under certain environmental conditions that do not involve social information. I think it's helpful to make sense of this using a metaphor from general medicine. Rheumatoid arthritis, for example, is a disease that is defined as being something that affects the joints. It has this in its name, 'arthritis', meaning joint inflammation, and yet the underlying disease process is an autoimmune one. As such, it's unsurprising that despite the cardinal symptom of rheumatoid arthritis being joint inflammation, it tends to affect organ systems throughout the body. Similarly, although the cardinal symptom of autism spectrum is one of social functioning, because the underlying brain-based deficit is one of information processing, it is also the case that we see challenges in other areas beyond simply social functioning. Given this, we ask the question: when do we make sense of an additional difficulty as being a comorbid psychiatric illness, versus when do we see this as simply part of the underlying autism spectrum disorder? We're going to now go through some specific examples of additional symptoms that are common in autism, and how we might make sense of these.