A study of the appropriateness of prescriptions for mental health disorders or pain among users of a specialist treatment service for substance use disorders

Background: People with substance use disorders (SUDs) often have co-existing physical and/or mental health conditions and are prescribed a large number of medications which may or may not be justified. Among this population, psychiatric medications and opioids are often involved in adverse events. There is, however, a lack of research on the quality of prescribing of these medications. In this thesis, the appropriateness of these medications is explored, as well as the response of prescribers in a specialist addiction service (SAS) to their inappropriate prescribing. Methods: A mixed methods design was utilised. A descriptive quantitative study using routinely available data was conducted to describe the scale of prescribing for service users. A second quantitative component involving questionnaires was carried out to assess the appropriateness of psychiatric medications and opioids in a sample of service users by SAS prescribers. Qualitative interviews were conducted with service users to explore their perspectives on the appropriateness of these medications while prescriber interviews explored how they responded to inappropriate prescribing. Results: The descriptive study showed that 27% of service users were prescribed four or more medications with almost half of them receiving antidepressants. The second study showed that nearly half of service users had at least one inappropriate psychiatric medication or opioid. Interviews with service users revealed that most of them benefited from these medications but that their use often involved making a compromise between risks and benefits. Benefits/risks of medications, prescriber expertise, nature of addiction and communication with service users and prescribers were considered by SAS prescribers before responding to inappropriate prescribing. It appears the need to maintain service users’ stability and well-being may lead to a greater focus on these issues when assessing the appropriateness of prescribing decisions. Conclusion: The quality of prescribing of opioids and psychiatric medications to service users referred to this SAS appeared to present room for improvement. Further research is required with the availability of a more mixed economy of service providers in the alcohol and drug treatment sector to establish if these findings are applicable.