The primary objective of the study is to assess the clinical course and functional outcome of comorbid mood disorders in children and adolescents with Intellectual Disability [IDD]

53 children and adolescents with varying levels of severity of IDD presenting with comorbid mood disorders diagnosed using Kiddie Schedule for Affective Disorder and Schizophrenia-DSM-5 version [KSADS] were recruited by convenient sampling with the exclusion of autism spectrum disorders. Vineland Social Maturity Scale [VSMS] is used to quantify the severity of ID. Developmental Behaviour Checklist-Parent [DBC-P] version is used to measure psychopathology, Clinical Global severity of illness [CGI-S] to quantify the clinical improvement, and Developmental Disabilities Children's Global Assessment of Severity [DD-CGAS] to assess functional improvement. Prospective naturalistic follow-up was done with assessment points at baseline, 1, 3- and 6-month timeline.

40 patients were followed up for 6 months period. Overall significant improvement is observed in the dependent variables like CGI, DDCGAS, and DBC-P from baseline to 3 months and then a plateau of improvement from 3 to 6 months. The diagnostic breakup of mood disorders is mania [N = 19], Depression [N = 12], and mixed affective state [N = 9]. Patients with mania had significant improvement in DBC score [F = 12.69, p < 0.001 in repeated measures ANOVA], DDCGAS [p < 0.001], and CGI score [p < 0.03] with an overall remission rate of 42.10% over 6 months period. Patients with depression had significant improvement in DBC score [F = 15.48, p < 0.001], DDCGAS, and CGI score [p < 0.001] with an overall remission rate of 41.7%. None of the patients with mixed affective states had clinical remission with no significant improvement observed in any of the dependent variables measuring course and outcome.

Comorbid psychiatric disorders in children and adolescents with IDD have a guarded prognosis compared to mood disorders in neurotypical children. Comorbid ADHD and caregiver stress majorly influenced the course and outcome in the current study.