Patient is a 14-year-old male with history of autism spectrum disorder who presents for psychiatric evaluation. Patient was diagnosed with autism at age 3 after his pediatrician noticed concerning signs including speech delay, limited social interaction, and repetitive play. On interview, patient’s mother shares that over the past few months patient has exhibited increased aggression resulting in altercations with others and destruction of property. Furthermore, she notes that patient has started eating less and has expressed concerns about contamination of food. She has seen him talk to unseen others and laugh inappropriately. The patient endorses hearing voices but he otherwise has difficulty engaging in the interview due to internal preoccupation and thought disorganization.
Autism spectrum disorder (ASD) and psychosis are distinct but closely related psychiatric conditions. In the twentieth century, Swiss psychiatrist Eugen Bleuler identified autism, which he defined as withdrawal from the world, as a core, pathognomonic symptom of schizophrenia. Since the 1970s and the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), ASD and psychosis have become recognized as separate diagnoses, but they remain highly comorbid. Up to 34.8% of those with ASD exhibit psychosis and 3.6-60% of those with schizophrenia present with autistic traits. Individuals with ASD are 3.5x more likely to develop psychosis than the general population. Both conditions share risk factors including advanced paternal age, pregnancy and birth complications, migration status, specific genetic pathways, abnormalities in brain development, neuroanatomical markers, and social cognition deficits. It is thought that the impairments in information processing seen in ASD may confer a risk for later psychosis.
Identifying psychosis in individuals with ASD can be challenging. First, patients with ASD may have difficulty communicating psychotic experiences, such as delusions and hallucinations due to the social communication impairments inherent to ASD and/or insufficient cognitive ability if they have comorbid intellectual disability. Additionally, overlapping symptoms in both conditions may create complications. For example, hallucinations may be misinterpreted as the anomalous perceptual experiences reported in ASD, or negative symptoms of psychosis, such as flat affect and social withdrawal, may be confused for difficulties with socio-emotional reciprocity seen in ASD.
Considering the overall course of illness can be helpful in distinguishing psychosis from ASD. While the onset of ASD is typically in early childhood, as early as 12-24 months of age, the onset of primary psychotic disorders is typically between late adolescence and the mid-thirties (there are exceptions to this pattern; for example, childhood-onset schizophrenia can be diagnosed before 13 years old). Furthermore, negative symptoms of psychosis typically worsen over time if untreated while autistic traits remain more stable.
There are also key differences between these two disorders that can aid in diagnosis. ASD is generally associated with an impairment in understanding the rules of common social interactions, greater impairment in theory of mind (the ability to understand and predict the mental states of others) and difficulty in distinguishing between one’s subjective perceptions and reality. On the other hand, individuals with psychosis tend to have a greater tendency towards external attributions for negative events and internal attributions for positive events. They are also more likely to demonstrate hostility bias, or the tendency to interpret the ambiguous behaviors of others as hostile.
Distinguishing ASD from psychosis is important, as it can allow for early intervention and treatment. Medications for these diagnoses can overlap; for instance, the second-generation antipsychotics aripiprazole and risperidone are used for both irritability associated with ASD and for psychosis. However, higher doses of such medications may be required in primary psychotic disorders compared to ASD. Additionally, diagnostic clarification can help guide therapy. While Applied Behavior Analysis may be most appropriate for an individual with ASD, Cognitive Behavioral Therapy for Psychosis might be recommended for individuals with psychosis. Understanding the differences and shared features of ASD and psychosis is crucial for accurate diagnosis and effective intervention, ultimately leading to improved outcomes for affected individuals.
Back to the Case: Patient was diagnosed with unspecified psychosis in addition to his existing diagnosis of autism spectrum disorder. He was started on aripiprazole, which was gradually titrated to 20mg daily. He and his mother reported improvement in his aggression, hallucinations, and paranoia on this medication. He was referred to the San Diego Regional Center for interventions related to his autism spectrum disorder and to a psychosis specialty clinic for interventions related to his psychosis.
AUTHOR:
Dr. Kristen Kim, MD
Child, Adolescent and Adult Psychiatrist
Vista Hill Foundation