Exploring fatigue in clinically depressed adolescents: a secondary analysis of the IMPACT study sample

BACKGROUND: Fatigue is a highly disabling symptom of adolescent depression, yet little is known about prevalence, associated characteristics, nor how fatigue might change during psychological intervention. METHODS: An exploratory secondary analysis was conducted using trial data from 465 adolescents (aged 11-17 years old) diagnosed with major depressive disorder who were randomised to receive one of three psychological interventions. Fatigue was measured as a binary variable (fatigue status; fatigued versus non-fatigued). We explored the prevalence of fatigue, associated demographic and clinical characteristics, changes in fatigue following psychological intervention, and the impact of baseline fatigue on improvements in depression severity and psychosocial functioning. RESULTS: Clinically significant fatigue was self-reported by 73% of adolescents at baseline. From self-report and diagnostic interviews, fatigue status was consistently associated with older age and higher depression severity. Through self-report only, depressed adolescents were also more likely to be fatigued if they were an ethnic minority, had more comorbidities, and higher psychosocial impairment. Fatigue status significantly decreased across all timepoints, irrespective of treatment arm, and continued to decrease after treatment was terminated. Furthermore, fatigue did not significantly predict overall treatment response or differential response between arms in relation to depression severity and psychosocial functioning. However, up to a third of depressed adolescents still reported residual fatigue at 86-weeks follow-up. CONCLUSIONS: In this exploratory study, fatigue is commonly reported by depressed adolescents and consistently associated with older age and higher depression severity, which are characteristics that could aid identification. Fatigue may decrease when receiving evidence-based psychological interventions for adolescent depression, but a proportion are left with residual symptoms. Further research is warranted to expand on these tentative findings.