Comorbid psychiatric and substance use disorders can be treated sequentially (one disorder is treated before the other), in parallel (two separate disorders are treated by two different treatment teams) or within an integrated treatment model in which both disorders are treated within the context of a single treatment program (Minkoff, 1989). Integrated treatments among people with psychotic disorders and substance abuse or dependence have been shown to be more effective to parallel or sequential approaches (Drake, Yovetich, Bebout, Harris & McHugo, 1997). A recent randomised controlled trial (Barrowclough, Haddock, Tarrier, Lewis et al., 2001) compared routine care and routine care plus an integrated intervention, addressing motivation for change and CBT for psychotic symptoms, plus family sessions and practical assistance. The mean percentage of change in days abstinent from all substances was greater in the integrated group. In practice, the primacy of psychiatric and substance use disorders is difficult to disentangle and both the psychiatric disorder and the substance use disorder should be addressed (Kavanagh, Mueser & Baker, in press). In acute settings, priority is given to treating symptoms that may be life threatening, for example, suicidal behaviour and integrated treatment for the psychiatric disorder and substance use may follow, once the immediate crisis has resolved. All clinicians working in the mental health and AOD fields should have sound suicide risk assessment skills and know when to appropriately refer to a specialist service when and if it is required.
Integrated treatments for depression and substance use problems are currently being investigated in several randomised controlled trials in Australia. Integrated psychotherapy and pharmacotherapy treatments have been advocated for psychostimulant dependence (Stitzer & Walsh, 1997) and for comorbid psychiatric and substance use disorders (Carroll, 1997) with the aim of broadening and enhancing outcomes.
Integrated interventions for comorbid psychostimulant use and anxiety disorders have not been widely researched. A small uncontrolled study by Brady and colleagues (Back et al., 2001; Brady et al., 2001) evaluated a treatment program for people with post-traumatic stress disorder (PTSD) and comorbid cocaine dependence that included imaginal and in vivo exposure for PTSD and CBT for cocaine dependence (see Chapter 5: Psychosocial interventions for a description of CBT for cocaine dependence). The dropout rate was high (38.5% attended at least 10 of 16 therapy sessions), but large effect sizes for both disorders were reported for those who remained in treatment.
Many psychostimulant users, particularly those whose use is harmful or hazardous, may benefit from short interventions such as MI. It may be possible to extrapolate from research performed among people with psychiatric disorders using drugs other than psychostimulants. Hulse and Tait (2002) have reported results of a randomised controlled trial of a brief motivational intervention among psychiatric in-patients who were drinking at a hazardous but not dependent level. At 6-month follow-up, the MI group reported a significantly greater reduction in weekly consumption of alcohol compared to an education group. MI has been found to be effective among people with psychotic illnesses and substance use disorders (Baker & Hambridge, 2002; Kavanagh, Young, White, Saunders et al., in press) and can be employed to enhance engagement in treatment for mental health problems (Baker & Hambridge, 2002).
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As part of the National Comorbidity Project Workshop, Kavanagh outlined principles for the development of treatments and services that are applicable to all people with psychiatric and substance use disorders (Teesson & Burns, 2001):
- effective management of comorbidity is likely to be cost-effective;
- service deployment should take into account factors such as the prevalence of disorders (e.g. anxiety and depression are common conditions) and the impact of substance use (e.g. amphetamine use may have stronger impact on people with schizophrenia);
- treatment services need to be responsive to heterogeneity in the type and severity of comorbidity and changes in presenting problems and motivation to change, and for treatment over time;
- treatment services need to be able to address multiple morbidities;
- confrontation and punitive communication styles should be avoided in the interests of improving engagement and retention in treatment; and
- existing treatments for individual disorders are likely to be useful in comorbidity, with more modifications needed among people with severe disorders.
Monitoring of service outcomes and the effectiveness of training and supervision on client outcomes should be a priority.