What's the science?

Suicide rates among adolescents have increased in recent years, but no well-established treatment exists to decrease death by suicide in at-risk youth. Dialectical behavioural therapy (DBT) involves cognitive-behavioural treatment focused on reducing self-harm, skills for managing distress and emotion regulation. It was recently demonstrated to be effective in reducing self-harm and suicidal ideation in adolescents, however, it is critical to understand the effects of DBT on suicide attempts. This week in JAMA Psychiatry, McCauley and colleagues report on a randomized clinical trial comparing the effects of DBT with individual and group supportive therapy (IGST), which acts as a control that matches DBT on nonspecific treatment factors closely.

How did they do it?

173 adolescents across multiple sites participated (aged 12-18). Participants had previously attempted suicide one or more times, had high levels of suicide ideation within the past year (Suicide Ideation Questionnaire Junior), had self-injured recently, and had 3 or more criteria for Borderline Personality Disorder. Participants were randomized to the DBT or IGST group, and both treatments involved 6 months of weekly individual and group therapies as well as parental participation. IGST treatment included group therapy, weekly consultation with a therapist, and emphasized belonging and connectedness. DBT treatment included skills training, group training with multiple families, and validation of interaction between families and adolescents. DBT treatment is similar to standard cognitive behavioural therapy but focuses on helping adolescents to ‘build a life worth living’ and on commitment to change. Suicide attempts and self harm were measured using the Suicide Attempt Self-Injury Interview (SASII), and suicidal ideation was measured using the Suicide Ideation Questionnaire Junior (SIQ-JR). A mixed model repeated measures analysis was used to compare treatment groups at four timepoints (baseline, 3, 6 (end of therapy), 9, and 12 months)

What did they find?

Between 0 (baseline) and 6 months of treatment, 10% of the DBT group and 22% of the IGST group attempted suicide. Between 6-12 months (a six month follow-up period), the rates were 7% of the DBT group and 10% of the IGST group. To analyze the number of suicide attempts and non-suicidal self injuries, a generalized linear mixed-effects model was used, and each participant was given a severity score. DBT improved each outcome measure. When the authors assessed the ‘number needed to treat’ they found that for each 8.46 youth who completed DBT instead of IGST, one additional youth would be free of suicide attempts (a small-medium effect size). Overall, the effects of DBT on primary outcomes were significant at 6 months but not at 12 months (after 6 months of follow-up). In a secondary analysis, self harm was classified in a binary manner instead of on a severity scale. A significantly larger proportion (46%) of youth who underwent DBT did not self harm by 6 months, compared to only 28% for IGST. By 12 months, the rates were 51% for the DBT group and 32% for the IGST group. There was also a large effect of DBT on reducing suicide ideation at 6 months (versus IGST), and a smaller effect at 12 months.