DBT combines behaviour-change strategies from CBT and acceptance strategies from Zen philosophy into an approach that focuses on client validation and behavioural change [397]. Originally developed for the treatment of adults with BPD who were also chronically suicidal, DBT has become the ‘gold standard’ evidence-based treatment for both BPD and suicidality [398]. Strategies to address changes in behaviour consist of behavioural analyses, skills training, contingency management, cognitive restructuring, and exposure-based strategies to reduce avoidance. Acceptance strategies include mindfulness and validation. DBT has been found to be efficacious in treating personality disorders (including those comorbid with AOD use) [399], and there is emerging research supporting its use for ED that are comorbid with AOD use disorders [400] (see Chapter B6).