Dual diagnoses – Severe Mental Illness and Substance Use Disorder. Part 2 – Effect of psychosocial interventions
3-page executive summary
The Norwegian Knowledge Centre for the Health Services was commissioned by The Norwegian Directorate of Health to summarize the effect of psychosocial treatment for persons with dual diagnosis.
The report summarizes the effects of psychosocial interventions for persons with dual diagnosis (co-occurring severe mental illness and substance use disorder). More specifically the effects on substance use, mental state, functioning and quality of life were investigated for the ten following psychosocial interventions: integrated treatment, case management, assertive community treatment, cognitive behavioural therapy (CBT), motivational interviewing, family therapy, social skills training, self-help groups, housing care and vocational rehabilitation. The report summarizes the effects of the interventions compared to other psychosocial interventions or treatment as usual.
We performed a literature search in MEDLINE, EMBASE, PsycINFO, Cochrane Library, CRD Databases and SveMed+ using search filters to identify systematic reviews. The inclusion of the literature was based on the following criteria:
Study design: Systematic reviews of randomized controlled trials (RCTs). Population: Persons over 15 years with severe mental illness and substance use disorder.
Interventions: Ten psychosocial interventions (as mentioned under “Objectives”).
Control interventions: Other psychosocial interventions, treatment as usual or no treatment. Outcomes: Substance use, mental state, functioning and quality of life.
We included systematic reviews according to the inclusion criteria, assessed the quality of the reviews and summarized the results. We used the GRADE system to evaluate the quality of the evidence and the strength of recommendations.
The literature search retrieved 495 titles. Of these, 13 were systematic reviews that matched our inclusion criteria. We assessed the quality of the reviews and identified the amount of overlap of included single studies. Based on this we included two systematic reviews appraised to have high and moderate quality. The two systematic reviews reported results from RCTs on seven of the ten psychosocial interventions: integrated treatment, case management, assertive community treatment, cognitive behavioural therapy (CBT), motivational interviewing, social skills training and self-
Studies on integrated treatment and motivational interviewing alone or in combination with CBT revealed statistically significant differences on some outcomes:
- One study compared integrated CBT (for alcohol disorder and social phobia) with CBT for the alcohol disorder alone. After three months the patients who received integrated CBT had a higher alcohol consumption than those in the control group. However, the recommendation strength for this result was very low. Studies on other types of integrated treatment revealed no statistically significant results.
- One study found that motivational interviewing led to a larger reduction in alcohol consumption (after six months) compared to psycho-educative treatment. The number of patients not abstaining from alcohol was lower in the group receiving motivational interviewing (42 %) than in the control group (92 %). Relative Risk was 0.36. This result was rated to have a low strength of recommendation.
- Two separate studies reported positive effects of motivational interviewing combined with CBT. One study found an improvement in social functioning compared to treatment as usual, after twelve months. Mean score on the Social Functioning Scale was 108.41 in the treatment group and 101.14 in the control group. However, the control treatment was not described in the systematic review. One study found an improvement in life satisfaction compared to i.a. psycho-educative treatment and group discussions, after six months. Life satisfaction score on the Brief Quality of Life Scale was 4.79 in the treatment group compared to 4.21 in the control group. WMD was 0.58. Both outcomes were rated to have a medium strength of recommendation.
Studies on case management, assertive community treatment, CBT alone, social skills training and self-help groups disclosed no statistically significant results.
We found no systematic reviews on the effects of family therapy, housing care and vocational rehabilitation.
There was some support for the effectiveness of motivational interviewing alone and in combination with CBT. However, the studies reported in the systematic reviews used a variety of interventions, study populations and outcome measures. The results were predominantly based on single studies, often with small population sizes, skewed outcome data and other methodological limitations. Consequently the majority of the results had a recommendation strength between medium and very low and it is difficult to reach a clear conclusion.
All studies included in the two systematic reviews were from USA, UK or Australia. Generalizability and application to the Norwegian population is thereby limited. The report does not summarize all research in the dual diagnoses field. In order to limit bias, we excluded results based on quasi-experimental and observational studies.
The systematic reviews reported no compelling evidence demonstrating the superiority of one type of psychosocial intervention over another intervention. However, there was some indication of motivational interviewing having a positive effect on alcohol consumption. There were also indications of motivational interviewing combined with cognitive behavioural therapy having a positive effect on social functioning and quality of life. It was not possible to conclude on the effects of the other ten psychosocial interventions. Further research is needed in order to improve the knowledge in this field.
The Norwegian Knowledge Centre for the Health Services summarises and disseminates evidence concerning the effect of treatments, methods, and interventions in the health services, in addition to monitoring the quality of the health services. Our goal is to support good decision making in order to provide patients in Norway with the best possible care. The Centre is organized under The Directorate of Health, but is scientifically and professionally independent. The Centre has no authority for developing or implementing health policies.
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Dobbeldiagnose – alvorlig psykisk lidelse og ruslidelse Del 1 Screening og diagnoseinstrumenter
(Rapport fra Kunnskapssenteret nr 21 - 2007)