Depression rates were higher in those with normal intellectual functioning than in their siblings or in cases with intellectual disability.

 Patients with autism spectrum disorder (ASD) sustain higher rates of mood disorders and suicidal attempts than their neurotypical peers.  The higher rate of depression in people with ASD than in their siblings is consistent with a role for environmental factors, which may be more operative in ASD patients with normal IQs. One environmental factor is their placement in regular classrooms, where their intellectual similarity to classmates may lead educators to expect typical social and communicative skills. Although patients may be aware of their social awkwardness, teachers and parents might consider their ineptness as volitional and thus not provide appropriate remediation.