Exploring autistic traits in adults with chronic depression: A clinical study

Background: Chronic depression is characterized by persistent or recurrent depressive symptoms, defined according to DSM criteria, and is associated with lack of empathy; deficits in social perception, interaction, and communication; and social withdrawal. These symptoms are reminiscent of autism spectrum disorders, yet the co-occurrence of autistic traits and chronic depression has been rarely explored. We explored measures of autistic traits in chronically depressed adult patients in order to further define and delineate the overlap of symptoms between chronic depression and autism spectrum disorders. Method: Three groups were tested: 31 patients with chronic depression, 27 patients with autism spectrum disorder, and 31 healthy controls. The Autism Spectrum Quotient (AQ) and the Empathy Quotient (EQ) were used to measure autistic traits. The severity of depression was measured by Beck's Depression Inventory. Results: The group of chronically depressed patients showed significantly elevated autistic traits according to both AQ and EQ measures. In addition, 48.4% of the patients with chronic depression showed AQ scores within the range of the broader autistic phenotype. Similar scores were found among 3.2% of the healthy controls and 100% of the patients with autism spectrum disorder. Conclusions: About half of the chronically depressed patients showed elevated autistic or autism-like traits. It remained unclear whether this was due to the state of chronic depression or a kind of premorbid autistic personality trait. The findings illustrate the need for further research to clarify the possible role of autistic traits in the development of chronic depression. Furthermore, they reveal that it might be clinically useful to focus on autism-like social impairments in therapy for chronic depression.