Among completers , 68.4 % ( 26/58 ) of those in the brief pulse group achieved remission versus 49.0 % ( 24/49 ) of those in the ultrabrief pulse group ( P = .019 ) , and the brief pulse group needed fewer treatment sessions to achieve remission : mean ( SD ) of 7.1 ( 2.6 ) versus 9.2 ( 2.3 ) sessions ( P = .008 ) .