Objective: To compare computer-delivered and therapist-delivered treatments for people with depression and comorbid addictive disorders.
Design: Randomised controlled clinical trial.
Setting and participants: Our study was conducted between January 2005 and August 2007 at seven study clinics in rural and urban New South Wales. Participants were 274 people who had a Beck Depression Inventory II (BDI-II) score ≥ 17 and were using alcohol and/or cannabis at harmful levels in the month before baseline. They were self-referred or referred from other sources such as outpatient drug treatment clinics, general practices and non-government support agencies.
Interventions: Participants were randomly allocated to receive (1) integrated cognitive behaviour therapy and motivational interviewing (CBT/MI) delivered by a therapist; (2) integrated CBT/MI delivered by computer, with brief therapist assistance at the end of each session (clinician-assisted computerised [CAC] treatment), or (3) person-centred therapy (PCT), consisting of supportive counselling given by a therapist (the control group). All three treatments were delivered according to a manual developed specifically for the study.
Main outcome measures: Changes in depression, alcohol use and cannabis use at 3 months after baseline; significant predictors of change in the primary outcome variables.
Results: Compared with computer- or therapist-delivered CBT/MI, PCT was associated with significantly less reduction in depression and alcohol consumption at 3 months. CAC therapy was associated with improvement at least equivalent to that achieved by therapist-delivered treatment, with superior results as far as reducing alcohol consumption. Change in depression was significantly predicted by change in alcohol use (in the same direction) and an ability to determine primacy, irrespective of whether this was for drug use or depression. Change in alcohol use was significantly predicted by changes in cannabis use and depression, and change in cannabis use by change in alcohol use. In the regression model, treatment allocation did not independently predict change, but was associated with significant reduction in depression and alcohol use at 3 months.
Conclusions: Over a 3-month period, CBT/MI was associated with a better treatment response than supportive counselling. CAC therapy was associated with greater reduction in alcohol use than therapist-delivered treatment.
Trial registration number: ACTRN12610000274077.