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

ABSTRACT

BACKGROUND: Functional 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. METHODS: Data 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. RESULTS: After 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 %]). LIMITATIONS: Short-term studies. CONCLUSIONS: These 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 %.