Evaluating integrated MI and CBT for people with psychosis and substance misuse: Recruitment, retention and sample characteristics of the MIDAS trial

Major problems with existing RCTs evaluating psychosocial interventions for psychosis and substance misuse have been identified, in particular small sample sizes, high attrition rates, and short follow up periods. With a sample size of 327 and a follow up of 2 years, the MIDAS trial in the UK is to date the largest RCT for people with psychosis and substance use and is evaluating an integrated MI and CBT (“MiCBT”) client therapy. Whilst the outcomes of the study are not yet available, data on recruitment and retention indicate that attrition rates in MIDAS are low and the majority of those allocated to treatment received a substantial number of therapy sessions. Sample characteristics are in line with those reported in epidemiological studies and are indicative of the challenges facing mental health services attempting to manage the client group: substance use is often longstanding, with frequent use at moderate or severe level and low motivation for change, and seen in the context of low levels of functioning and significant psychopathology. We conclude that this is a methodologically robust study that will have results generalisable to mental health services.