Background: Relative to other aspects of Down syndrome, remarkably little is known about the psychiatric problems experienced by youth and young adults with this syndrome and if these problems differ from others with intellectual disabilities. Yet adolescence and young adulthood are particularly vulnerable time periods, as they involve multiple life transitions in educational, medical, and other service systems.
Methods: This study compared the psychiatric diagnoses of 49 adolescent and young adult patients with Down syndrome to 70 patients with other intellectual disabilities (IDs). The groups were similar in age, gender, and level of intellectual impairment. The 119 participants, aged 13 to 29 years (M = 21) were evaluated in one of two specialized psychiatric clinics.
Results: In contrast to previous literature, those with Down syndrome versus other IDs had significantly higher rates of psychosis NOS or depression with psychotic features (43% versus 13%). Unlike the ID group, psychosis was predominantly seen in females with Down syndrome. Marked motoric slowing in performing routine daily activities or in expressive language was manifested in 17% of patients with Down syndrome. No group differences were found in anxiety or depressive disorders, and the ID group had significantly higher rates of bipolar and impulse control disorders.
Conclusions: These preliminary observations warrant further studies on genetic, neurological, and psychosocial factors that place some young people with Down syndrome or other IDs at high risk for severe psychiatric illness.
Keywords: Catatonia; Depression; Down syndrome; Intellectual disabilities; Psychosis.