Compared with the DBT-I group , interventions that included skills training resulted in greater improvements in the frequency of NSSI acts ( F1 ,85 = 59.1 [ P < .001 ] for standard DBT and F1 ,85 = 56.3 [ P < .001 ] for DBT-S ) and depression ( t399 = 1.8 [ P = .03 ] for standard DBT and t399 = 2.9 [ P = .004 ] for DBT-S ) during the treatment year .