BACKGROUND: Previous studies reported a high prevalence of depression among 
patients with autism spectrum disorder (ASD) and suggested a relationship 
between ASD and suicidality. However, whether ASD independently increases the 
risk of attempted suicide regardless of depression has not been determined.
METHODS: Using the Taiwan National Health Insurance Research Database, 5,618 
adolescents aged 12-17 years and young adults aged 18-29 years with ASD 
(ICD-9-CM code: 299) and 22,472 age- and sex-matched controls were enrolled 
between 2001 and 2009 and followed to the end of 2011. Any suicide attempt was 
identified during the follow-up period.
RESULTS: Patients with ASD had a higher incidence of suicide attempts (3.9% vs 
0.7%, P < .001) than did those without ASD. Both adolescents (HR = 5.79; 95% CI, 
3.98-8.41) and young adults (HR = 5.38; 95% CI, 3.58-8.06) with ASD were more 
likely to attempt suicide in later life after adjusting for demographic data and 
psychiatric comorbidities. Sensitivity analyses after excluding the first year 
(HR = 4.52; 95% CI, 3.39-6.03) or first 3 years (HR = 3.36; 95% CI, 2.40-4.70) 
of observation showed consistent findings.
CONCLUSIONS: Patients with ASD had an increased risk of suicide attempts 
compared with those without ASD. ASD was an independent risk factor of attempted 
suicide. Further studies are needed to clarify the underlying pathophysiology 
between ASD and suicidality and to elucidate whether prompt intervention for ASD 
may reduce this risk.