Computer-based psychological treatment for comorbid depression and problematic alcohol and/or cannabis use: a randomized controlled trial of clinical efficacy Frances J. Kay-Lambkin 1 , Amanda L. Baker 2 , Terry J. Lewin 3 & Vaughan J. Carr 4 Centre for Brain and Mental Health Research, University of Newcastle, Newcastle, NSW, Australia, 2300 and National Drug and Alcohol Research Centre, University of New South Wales, Sydney NSW 2052, Australia, 1 Centre for Brain and Mental Health Research, University of Newcastle, Newcastle, NSW 2300, Australia, 2 Centre for Brain and Mental Health Research and Hunter New England Mental Health, Newcastle, NSW 2300, Australia 3 and Centre for Brain and Mental Health Research, University of Newcastle, Newcastle, NSW 2300, Australia and Schizophrenia Research Institute, Sydney, Australia 4 ABSTRACT Aims To evaluate computer- versus therapist-delivered psychological treatment for people with comorbid depression and alcohol/cannabis use problems. Design Randomized controlled trial. Setting Community-based participants in the Hunter Region of New South Wales, Australia. Participants Ninety-seven people with comorbid major depression and alcohol/cannabis misuse. Intervention All participants received a brief intervention (BI) for depressive symptoms and substance misuse, followed by random assignment to: no further treatment (BI alone); or nine sessions of moti- vational interviewing and cognitive behaviour therapy (intensive MI/CBT). Participants allocated to the intensive MI/CBT condition were selected at random to receive their treatment ‘live’ (i.e. delivered by a psychologist) or via a computer-based program (with brief weekly input from a psychologist). Measurements Depression, alcohol/cannabis use and hazardous substance use index scores measured at baseline, and 3, 6 and 12 months post-baseline assessment. Findings (i) Depression responded better to intensive MI/CBT compared to BI alone, with ‘live’ treatment demonstrat- ing a strong short-term beneficial effect which was matched by computer-based treatment at 12-month follow-up; (ii) problematic alcohol use responded well to BI alone and even better to the intensive MI/CBT intervention; (iii) intensive MI/CBT was significantly better than BI alone in reducing cannabis use and hazardous substance use, with computer- based therapy showing the largest treatment effect. Conclusions Computer-based treatment, targeting both depres- sion and substance use simultaneously, results in at least equivalent 12-month outcomes relative to a ‘live’ intervention. For clinicians treating people with comorbid depression and alcohol problems, BIs addressing both issues appear to be an appropriate and efficacious treatment option. Primary care of those with comorbid depression and cannabis use problems could involve computer-based integrated interventions for depression and cannabis use, with brief regular contact with the clinician to check on progress. Keywords Comorbidity, computer-based treatment, depression, substance use. Correspondence to: Frances Kay-Lambkin, Centre for Brain and Mental Health Research, University of Newcastle, PO Box 833, Newcastle, NSW, 2300, Australia. E-mail: frances.kaylambkin@newcastle.edu.au Submitted 6 June 2008; initial review completed 29 September 2008; final version accepted 20 October 2008 INTRODUCTION Depression and alcohol/other drug (AOD) use disorders are two of the three most common and disabling mental disorders [1]. These disorders also co-occur with consid- erable frequency, a phenomenon referred to as ‘comor- bidity’ [2]. Although much is known about the epidemiology and characteristics of people with comor- bid disorders, much less is known about effective treat- ment strategies to assist this increasingly prevalent clinical group, who often do not access treatment for their conditions [3]. Computers and the internet offer a potential solution [4]. Treatment via these modalities may enable treatment RESEARCH REPORT doi:10.1111/j.1360-0443.2008.02444.x © 2009 The Authors. Journal compilation © 2009 Society for the Study of Addiction Addiction, 104, 378–388