“New-Onset Psychiatric Disorders in Individuals With Autism”, Jane Hutton, Susan Goode, Margaret Murphy, Ann Le Couteur, Michael Rutter2008-07-01 (anxiety, BP & autism)⁠:

A follow-up study to at least the age of 21 years of 135 individuals with an autism spectrum disorder diagnosed in childhood and an IQ of over 30 was conducted. The study is distinctive in its large size, low attrition rate and use of systematic interviews to obtain clinical information. Questionnaires completed by caregivers asked about the development of new psychiatric disorders. For the 39 individuals with a possible new disorder, a detailed psychiatric assessment was undertaken through parental interview.

Of all participants, 16% developed a definite new psychiatric disorder. A further 6% developed a possible new disorder. 5 individuals developed an obsessive-compulsive disorder and/or catatonia; 8 an affective disorder with marked obsessional features; 3 complex affective disorders; 4 more straightforward affective disorders; one a bipolar disorder; and one an acute anxiety state complicated by alcohol excess. There was no case of schizophrenia.