Substance use is common in people with mental health problems, and this can have important negative consequences for health and social function. The high comorbidity of mental health problems and substance use is a major contributor to the shorter life expectancy of this population – a person with a severe mental disorder can expect to live up to 20 years less than someone else without a mental disorder. Clearly there is a pressing need for effective interventions that can reduce this burden.
This review, by Hunt and colleagues under the aegis of the Cochrane Schizophrenia Group, assessed the effects of psychosocial interventions for reducing substance use in people with serious mental health problems, compared with usual care. It included all randomised controlled trials of psychosocial interventions compared with usual care, and analysed data on an intention-to-treat basis, for both categorical (e.g., death from all causes) and continuous (e.g., mental state) outcomes. Data were combined in a meta-analysis using random effects methods.
A total of 32 trials, comprising 3,165 participants, were included. This included:
- 4 trials (n = 765) of long-term integrated care
- 4 trials (n = 163) of non-integrated intensive case management
- 7 trials (n = 878) of motivational interviewing plus cognitive behavioural therapy (CBT)
- 2 trials (n = 152) of CBT alone
- 8 trials (n = 509) of motivational interviewing alone
- 2 trials (n = 94) of skills training
- 2 trials (n = 206) of contingency management
The outcomes that were assessed included substance use (including relapse), loss to treatment, death, global assessment of functioning, general life satisfaction and measures of mental health. It was not possible to summarise all findings, either due to skewed data or because the outcome of interest was not measured.
- There was no evidence of any benefit, relative to usual care, of long-term integrated care, non-integrated intensive case management, motivational interviewing plus CBT, CBT alone, skills training, or contingency management.
- There was some evidence for:
- a benefit of motivational interviewing in terms of numbers reporting for the first after-care appointment (1 trial, n = 93, RR 0.69, 95% CI 0.53 to 0.90)
- and abstaining from alcohol (1 trial, n = 28, RR 0.36, 95% CI 0.17 to 0.75)
- but not for other outcomes
- In general, the quality of evidence was rated as low or very low, due to high or unclear risk of bias (e.g., due to poor trial methods or reporting of results)
- The sample size of individual trials was also low, increasing imprecision
The results were extremely disappointing – there was no compelling evidence to support any one psychosocial treatment over another in this population, either to reduce substance use or improve mental health. The methodological limitations of the literature as a whole also limit the interpretation of these results, suggesting that even the benefits observed should be treated with caution.
The authors conclude that there is a clear need for further high-quality trials which address these limitations, in order to improve the evidence base in this important area. This is an important conclusion – while a number of psychosocial interventions for substance use in people with mental health problems are available, they do not seem to work (or at least we have no clear evidence that they do). Better evidence is required regarding those interventions currently available, and most likely better interventions are required as well.
It may also be helpful to focus on harm reduction as an outcome, as well as abstinence. For example, NICE has recently introduced guidelines for the tobacco harm reduction, which includes provision for those working in secure mental health units.
If the ultimate aim is to reduce the wider health burden associated with mental health problems, targeting substance use should be an important priority.
Hunt GE, Siegfried N, Morley K, Sitharthan T, Cleary M. Psychosocial interventions for people with both severe mental illness and substance misuse. Cochrane Database of Systematic Reviews 2013, Issue 10. Art. No.: CD001088. DOI: 10.1002/14651858.CD001088.pub3.
Tobacco: harm-reduction approaches to smoking. NICE public health guidance, PH45, June 2013.