Autism spectrum disorder patients who attempt suicide are younger and more likely to have comorbid adjustment disorder, compared with suicidal patients without autism.
The findings come from what the investigators say is the "first study to compare suicide attempts in [autism spectrum disorder] and [non–autism spectrum disorder] patients in adults in the emergency department, according to Dr. Koji Kato and colleagues (Gen. Hosp. Psychiatry 2013;35:50-3).
Dr. Kato looked at 587 consecutive adult patients who attempted suicide and were hospitalized at the Advanced Critical Care Center of Tokai (Japan) University Hospital between April 2010 and December 2011.
Overall, 43 of the 587 subjects (7.3%) were found to have autism spectrum disorders, diagnosed by family history and also by administration of the Autism-Spectrum Quotient–Japanese version during hospitalization, wrote Dr. Kato of Tokai University, Kanagawa, Japan.
"Poor interpersonal problem-solving skills or impulsive behavior, which is characteristic of individuals with [autism spectrum disorders], had been linked with an increased risk of suicidal behavior among youth." -Dr. Kato, et. al.
The researchers then began to characterize these patients in comparison with their nonautism counterparts. First, they found that patients with autism spectrum disorder were significantly younger than were their nonautism counterparts (33.7 years versus 42.5 years, respectively; P = .001) and also much more likely to be male (81.4% vs. 30.3%; P less than .001).
Similarly, more than three-quarters of the autism spectrum patients were unmarried, compared with just over one-third of nonautism patients (76.7% vs. 37.5%; P less than .001) and were in fact more likely to be living alone at the time of the attempt (41.9% vs. 18.9%; P less than .001).
Next, the authors looked at psychiatric diagnoses. They found that patients with an autism spectrum disorder were much less likely to have a diagnosis of a mood disorder, compared with their nonautism counterparts (18.6% vs. 34.2%, P = .043), although they were much more likely to have adjustment disorders (70.0% vs. 41.5%, P less than .001).
Commenting on the marked difference in age between autism spectrum disorder patients and the rest of the cohort, they wrote: "Poor interpersonal problem-solving skills or impulsive behavior, which is characteristic of individuals with [autism spectrum disorders], had been linked with an increased risk of suicidal behavior among youth."
Indeed, other research "suggests that suicidal acts are more frequent in adolescents with Asperger syndrome, perhaps due to bullying and feelings of inadequacy in coping with the social demands that occur during puberty."
Looking at the documented higher incidence of single individuals and individuals living alone in the autism spectrum disorders group "could be explained by autism spectrum disorder characteristics such as lack of social reciprocity and/or repeated failure to develop peer relationships since childhood or adolescence," they added.
Finally, they addressed the prevalence of mood and adjustment disorders among the cohort.
They conceded that the individuals with autism spectrum disorders in this study "were compared to control subjects who had also attempted suicide" versus patients in the general population, which likely skews the significance of the prevalence of psychiatric disorders as a risk factor for suicide.
Nevertheless, "not only mood disorders but also an adjustment disorder may contribute to suicidal behavior in individuals with autism spectrum disorders," they wrote.
Dr. Kato disclosed that the study was partly funded by grants from pharmaceutical companies, including the makers of antidepressant and antipsychotic medication, and to one of the coinvestigators. The investigators disclosed no other personal conflicts of interest.