Variability in Clinical Outcomes for Youths Treated for Subthreshold Severe Mental Disorders at an Early Intervention Service

Objective: The study assessed the longitudinal clinical and functional outcomes of young people receiving early intervention services for subthreshold manifestations of severe mental disorders at a youth mental health service in Sydney, Australia. Methods: The six-month, prospective, longitudinal study collected data on clinical outcomes of 243 young people treated for subsyndromal presentations of putative major mental disorders. Reliable change index scores and effect sizes were calculated to compare results at baseline, three months, and six months for measures of symptoms (Brief Psychiatric Rating Scale [BPRS]), psychological distress (Kessler 10 [K10]), and social functioning (Social and Occupational Functioning Assessment Scale [SOFAS]). Results: There was variability in outcomes across each of the outcome measures, with 25%, 33%, and 23% of patients showing reliable improvement and 9%, 13%, and 5% showing reliable deterioration for the SOFAS, K10, and BPRS, respectively. Many individuals did not show linear improvement or deterioration, with reliable change within individuals varying significantly between the zero- to three-month and three- to six-month time points. After the analyses were controlled for covariates, baseline severity or impairment and number of sessions with a psychiatrist or psychologist contributed a small (4%-8%) but significant amount to the total variance in outcomes at six months. Conclusions: Most individuals did not show significant deterioration, and about one in four showed reliable improvement by six months. However, individual patterns of change were diverse, highlighting the importance of further research into factors that influence treatment outcomes among youths with subthreshold presentations of severe mental disorders.