We can expect no single assessment or treatment process will be effective for all types of comorbidity, because of the substantial degree of heterogeneity in those disorders. For the large numbers of people with anxiety or depression and alcohol misuse, brief interventions may prove to be both effective and practicable, especially if they can be delivered within a primary care setting. Brief interventions may even prove effective in people with psychosis who have low levels of cognitive deficit and low dependence, but further data needs to be obtained before we can be confident of this conclusion. For people with high levels of substance dependence or deficits in critical skills, more intensive interventions may be required, and in the case of people with chronic cognitive deficits, these may need to take the form of harm reduction interventions within the context of long-term supportive care. Some of the key current areas of knowledge may be summarised as follows:

  • Screening measures for SUD need to be able to detect problems that may emerge in MD at low levels of substance intake and dependence. Some measures that are used in the general population such as the AUDIT or SDS can be confidently applied, and some measures such as the DALI and DrugCheck that are designed specifically for comorbid populations show promise. Self-reports of substance intake can be reliable and valid, even in people with psychoses, as long as rapport has been developed and incentives for accuracy are present. Biochemical assays and collateral data do not substantially add to accuracy, but data in the general population suggests that awareness that such measures are being collected may add to accuracy of self-report. Measures of readiness to change substance use, readiness for treatment and insight into mental disorders are also available.

  • Screening measures for mental disorders appear to be applicable to those presenting with substance use disorders, although there are few specific data on the issue.

  • Engagement and motivational enhancement appear to be effective in comorbid substance use and mental disorders in increasing rates of engagement in treatment and substance control attempts; although multiple engagement attempts may be required for many people, and a substantial proportion may remain unmotivated to change. While an abstinence goal may often be the option most likely to result in a positive outcome, intermediate goals will initially be selected by many consumers.

  • An intervention that integrates management of the substance use and mental disorders is indicated in severe mental illness, and is also likely to be most effective in other contexts where there are strong mutual influences between the disorders.

  • Standard pharmacotherapy for depression is effective in people with comorbid depression and alcohol misuse. Atypical antipsychotics are preferred to typical drugs in people with psychosis and substance use disorders, and clozapine in particular has shown beneficial effects on the substance misuse as well as the psychotic symptoms. Nicotine replacement appears safe in those with comorbid mental disorders including psychosis.
Top of pageHowever, the literature on assessment and management of comorbid substance use and mental disorders is sparse, and many questions remain unanswered. Some examples are:
  • Is integrated treatment superior to parallel or sequential management in anxiety and depression?

  • What are the critical effective elements of interventions for comorbidity?

  • Are acamprosate and naltrexone effective treatments for alcohol dependence in psychosis?

  • What are the effective treatments for opiate dependence in mental disorders?

  • Can effective management of substance use and mental disorders in primary care be demonstrated, and what will that comprise of?

  • How can treatments for such comorbidity be successfully disseminated in existing services, and across rural and remote areas?
Answering these questions will be critical to the outcomes of people with comorbidity of substance misuse and mental disorders.