Day 1 and Day 3 patterns of wrist activity for ketamine-treated patients who responded (>50% decrease in Montgomery-Asberg Depression Rating Scale (MADRS) score) within 1 day of ketamine infusion compared with non-responders. (Left panel) Responders (R, red) compared with non-responders (NR, blue) 1 day after ketamine infusion (Day 1). (Right panel) Responders (R, red) who maintained the 50% decrease in MADRS score compared with patients who did not meet response criteria (NR, blue) on Day 3. The raw MADRS scores for each group are shown as inserts for each day. On Day 1, the phase of the 24-h pattern of activity in ketamine responders differed from non-responders (p = 0.0038). On Day 3 the amplitude (p = 0.0488) of the 24-h pattern significantly differed between responders and non-responders. Group sizes are: D1 (R = 21, NR = 30) and D3 (R = 13, NR = 35)