Agomelatine significantly reduced mean ( SD ) HARS total score ( agomelatine-placebo difference : 4.71 [ 1.03 ] , P < .0001 ) and had significant effects on secondary outcome measures , including psychic and somatic HARS subscales , response rate ( estimate [ standard error ] ) ( agomelatine-placebo difference : 27.4 % [ 5.9 % ] , P < .0001 ) , remission on the HARS ( agomelatine-placebo difference : 16.8 % [ 5.4 % ] , P = .002 ) , Clinical Global Impressions-Severity of Illness scale ( CGI-S ) ( P < .001 ) , functional impairment ( P < .0001 ) , and sleep quality ( P < .001 ) .