RESUMEN
OBJECTIVES: The purpose of this study was to evaluate the effects of homework-task difficulty and electronic-diary reminders on written homework completion during cognitive-behavioural therapy (CBT) for addiction. Completion of homework is an important element in CBT that may affect outcome. DESIGN: All participants received all combinations of our two interventions in a factorial 2 × 2 counterbalanced Latin-square design. METHODS: Methadone-maintained cocaine and heroin users were given homework between each of 12 weekly CBT sessions and carried electronic diaries that collected ecological momentary assessment (EMA) data on craving and exposure to drug-use triggers in four 3-week blocks assessing two levels of homework difficulty and prompted and unprompted homework. RESULTS: Neither simplified (picture-based) homework nor electronic reminders increased homework completion. In EMA reports, standard but not simplified homework seemed to buffer the craving that followed environmental exposure to drug cues. EMA recordings before and after the CBT intervention confirmed a decrease over time in craving for cocaine and heroin. CONCLUSIONS: These findings demonstrate the utility of EMA to assess treatment effects. However, the hypothesis that simplified homework would increase compliance was not supported. PRACTITIONER POINTS: Our simplifications of homework assignments for cognitive-behavioural therapy were mostly ineffective, or even counterproductive, perhaps because they did not engage sufficient depth of processing or because they were perceived as too simplistic. Our reminder beeps for homework were mostly ineffective, or even counterproductive, suggesting that mobile electronic interventions for substance-use disorders may need to be more interactive.