The Functioning Assessment Short Test (FAST): Clinically meaningful response threshold in patients with major depressive disorder receiving antidepressant treatment

Abstract

BackgroundFunctional impairment is common in patients with major depressive disorder (MDD). The Functioning Assessment Short Test (FAST) provides a detailed clinician-rated assessment of functioning across multiple aspects of daily life. This study aimed to establish clinically relevant response thresholds for the FAST in patients with MDD receiving antidepressant treatment. MethodsData were derived from three 8-week clinical trials of antidepressant therapy in patients with MDD that included assessment of functioning using the FAST as a pre-specified endpoint. The minimal clinically important difference (MCID) and threshold for response in terms of change in FAST total score were determined using anchor-based methods. ResultsAfter 8 weeks of antidepressant treatment, the mean reduction in FAST total score in patients considered clinically minimally improved (Clinical Global Impression–Improvement [CGI-I] score of 3) was 7–9 points (~20 % reduction). The threshold for functional response (reduction in FAST total score from baseline in patients with a CGI-I score of ≤2 at week 8) was 16–19 points (~50 % reduction). The threshold for functional response was higher in patients with MDD and comorbid generalized anxiety disorder than in those with MDD alone (mean reduction in FAST total score at 8 weeks: 26 points [63 %]). LimitationsShort-term studies. ConclusionsThese results provide further validation of the FAST for assessing functioning in patients with MDD. In patients with MDD, the suggested MCID for FAST total score is 7–9 points and the proposed threshold for response is a reduction from baseline of approximately 50 %.