A multi-center, randomized controlled trial of a group psychological intervention for psychosis with comorbid cannabis dependence over the early course of illness Kevin Madigan a, b, ⁎, Daria Brennan a, b , Elizabeth Lawlor a, b , Niall Turner a, b , Anthony Kinsella b, c , John J. O'Connor d , Vincent Russell e, f , John L. Waddington c, e , Eadbhard O'Callaghan a, b, † a St. John of God Adult Mental Health Services, Cluain Mhuire Family Centre, Blackrock, Co. Dublin, Ireland b DETECT Early Intervention in Psychosis Service, Blackrock, Co. Dublin, Ireland c Molecular & Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland d Drug Treatment Centre Board, Dublin, Ireland e Cavan–Monaghan Mental Health Service, Cavan Hospital, Cavan, Ireland f Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland abstract article info Article history: Received 25 May 2012 Received in revised form 12 September 2012 Accepted 21 October 2012 Available online 24 November 2012 Keywords: Substance abuse Psychosis Psychological therapy RCT Background: Patients who experience the onset of psychotic illness with a comorbid diagnosis of cannabis de- pendence experience poor clinical outcomes. Few studies have identified interventions that reduce cannabis use and improve clinical outcome in this population. Aims: We undertook a multi-center, randomized controlled trial of a group psychological intervention for psychosis with comorbid cannabis dependence to determine whether there was any impact on cannabis use symptoms, global functioning, insight, attitudes to treatment and subjective quality of life. Method: Across three centers, we compared a group psychological intervention, based on cognitive behavioral therapy and motivational interviewing, with treatment as usual among patients experiencing their first psy- chotic episode or early in the course of psychotic illness. Substance misuse and indices of clinical outcome were assessed at baseline, 3 months and 1 year. Results: At 3 month and 1 year follow-ups, there was no evidence for an intervention effect on cannabis use, symptoms, global functioning insight or attitude to treatment. However, the intervention improved subjec- tive quality of life at 3 months and this effect was sustained at 1 year. Conclusions: Over the early phase of psychotic illness, group psychological interventions for those with comorbid cannabis dependence improved subjective quality of life. However, this was not associated with reduction in use of cannabis or improvement in clinical outcomes. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Substance misuse is the predominant comorbidity of schizophre- nia (Buckley et al., 2009) with cannabis being the most commonly used substance (Koskinen et al., 2010). Up to 60% of patients ex- periencing a first psychotic episode have used cannabis in the 12 months prior to presentation to treatment services (Wade et al., 2006). Emerging evidence supports the hypothesis of cannabis as a causal factor in the development of psychotic illness (Moore et al., 2007) with cannabis users developing psychotic symptoms at an ear- lier age than non-cannabis users (Large et al., 2011). Those patients who continue to use cannabis are also more likely to have poorer out- comes and to experience a greater number of relapses and longer periods in hospital (Isaac et al., 2005). Poor insight and inadequate ad- herence to prescribed treatment are highly prevalent among substance abusers (Kamali et al., 2001) with increased risk of loss to treatment services over the first 12 months following the onset of psychosis (Miller et al., 2009). Cannabis users experience positive symptoms of psychosis with greater frequency and severity (Machielson et al., 2010) without reduction in negative symptoms (Compton et al., 2004). However, comorbid cannabis use is often associated with poorer psychosocial outcomes relating to occupation (Claussen, 1999) and housing (Drake and Osher, 1991). In terms of quality of life, adverse fi- nancial circumstances, social isolation and interpersonal conflict appear related to comorbid substance misuse (Kessler, 1995). Despite these poor clinical outcomes, there are few interventions of proven efficacy for psychotic patients with comorbid substance misuse. A Cochrane review of psychosocial interventions for people with both severe mental illness and substance misuse (Cleary et al., 2008) found 25 randomized controlled trials of sufficient quality that compared psychosocial interventions with standardized care in reducing substance misuse. Only one randomized controlled trial Schizophrenia Research 143 (2013) 138–142 ⁎ Corresponding author at: St. John of God Adult Mental Health Services, Cluain Mhuire Family Centre, Newtownpark Avenue, Blackrock, Co. Dublin, Ireland. Tel.: +353 1 217 2100. E-mail address: kevin.madigan@sjog.ie (K. Madigan). † Deceased. 0920-9964/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.schres.2012.10.018 Contents lists available at SciVerse ScienceDirect Schizophrenia Research journal homepage: www.elsevier.com/locate/schres