Scientific Summary Growing concern about suicide risk among individuals with autism spectrum disorder (ASD) necessitates population‐based research to determine rates in representative samples and to inform appropriate prevention efforts. This study used existing surveillance data in Utah to determine incidence of suicide among individuals with ASD over a 20‐year period, and to characterize those who died. Between 1998 and 2017, 49 individuals with ASD died by suicide. Suicide cumulative incidence rates did not significantly differ between 1998 and 2012 across the ASD and non‐ASD populations. Between 2013 and 2017, the cumulative incidence of suicide in the ASD population was 0.17%, which was significantly higher than in the non‐ASD population (0.11%; P < 0.05). During this period, this difference was driven by suicide among females with ASD; suicide risk in females with ASD was over three times higher than in females without ASD (relative risk (RR): 3.42; P < 0.01). Among the individuals with ASD who died by suicide, average age at death and manner of death did not differ significantly between males and females. Ages at death by suicide ranged from 14 to 70 years ( M [SD] = 32.41[15.98]). Individuals with ASD were significantly less likely to use firearms as a method of suicide (adjusted odds ratio: 0.33; P < 0.001). Study results expand understanding of suicide risk in ASD and point to the need for additional population‐based research into suicide attempts and ideation, as well as exploration of additional risk factors. Findings also suggest a need for further study of female suicide risk in ASD. Autism Research 2019, 12: 658–666 . © 2019 The Authors. Autism Research published by International Society for Autism Research published by Wiley Periodicals, Inc. Lay Summary This study examined suicide risk among individuals with autism spectrum disorder (ASD) in Utah over a 20‐year period. Risk of suicide death in individuals with ASD was found to have increased over time and to be greater than in individuals without ASD between 2013 and 2017. Females with ASD were over three times as likely to die from suicide as females without ASD. Young people with ASD were at over twice the risk of suicide than young people without ASD. Individuals with ASD were less likely than others to die from firearm‐related suicides.

Understanding the complex relationships among factors that may predict the outcomes of young adults with autism spectrum disorder (ASD) is of utmost importance given the increasing population undergoing and anticipating the transition to adulthood. With a sample of youth with ASD (n = 1170) from the National Longitudinal Transition Study-2, structural equation modeling techniques were used to test parent expectations as a mediator of young adult outcomes (i.e., employment, residential independence, social participation) in a longitudinal analysis. The mediation hypothesis was confirmed; family background and functional performance variables significantly predicted parent expectations which significantly predicted outcomes. These findings add context to previous studies examining the role of parent expectations on young adult outcomes and inform directions for family-centered interventions and future research.

It has been proposed that early differences in sensory responsiveness arise from atypical neural function and produce cascading effects on development across domains. This longitudinal study prospectively followed infants at heightened risk for autism spectrum disorder (ASD) based on their status as younger siblings of children diagnosed with ASD (Sibs-ASD) and infants at relatively lower risk for ASD (siblings of typically developing children; Sibs-TD) to examine the developmental sequelae and possible neurophysiological substrates of a specific sensory response pattern: unusually intense interest in nonsocial sensory stimuli or "sensory seeking." At 18 months, sensory seeking and social orienting were measured with the Sensory Processing Assessment, and a potential neural signature for sensory seeking (i.e., frontal alpha asymmetry) was measured via resting state electroencephalography. At 36 months, infants' social symptomatology was assessed in a comprehensive diagnostic evaluation. Sibs-ASD showed elevated sensory seeking relative to Sibs-TD, and increased sensory seeking was concurrently associated with reduced social orienting across groups and resting frontal asymmetry in Sibs-ASD. Sensory seeking also predicted later social symptomatology. Findings suggest that sensory seeking may produce cascading effects on social development in infants at risk for ASD and that atypical frontal asymmetry may underlie this atypical pattern of sensory responsiveness.

Sensory features may interfere with development of adaptive behaviors, suggesting a need for effective interventions addressing sensory features early in development.