QUESTION-307: In dialectical behaviour therapy, do skills-homework completion and phone coaching predict falling urges and less frequent target behaviour once baseline functioning and motivation are controlled and patients with missing diary data are kept, and does skill use between sessions mediate the change?

Why it is a question

THEORY-922 holds that, among 56 of 88 patients in one DBT intensive outpatient programme, homework completion correlated with falling suicide and substance-use urges and phone coaching with falling self-harm urges, uncorrected for multiple comparisons, with no association with how often the behaviours occurred. Nothing measured skill use between sessions, so the record’s DBT example (CLAIM-443, CLAIM-349), in which practice changes which process is recruited, has no evidence about what practice changed.

What would answer it

A larger sample, or a second programme, with the analysis specified in advance and corrected for multiple comparisons, finding homework completion associated with falling suicide or substance-use urges and coaching with falling self-harm urges, with intention-to-treat handling of dropouts and missing diary days; better, a randomized component design that varies homework or coaching. The associations are refuted if they vanish with baseline functioning and motivation controlled, or in the full sample including those with missing diary data. A causal claim about generalization needs a measure of skill use as a mediator.