Psychiatric comorbidity in substance use disorder

Psychiatric comorbidity in substance use disorder
A large proportion of people who use drugs have a mental health diagnosis. The question then becomes why do some people with mental health illnesses or mental health diagnoses use drugs? For some people it is a coping mechanism and form of self-medication to deal with trauma, pain, loneliness, stigma and isolation. Drugs can also often be used to manage boredom and as a form of escapism from the daily realities of life. Drugs can also be used as a form of self harm and also due to physical dependence on the drug. There can also be the social factor involved in drug use if one's peers are also using drugs. Some medications used to treat mental health disorders can result in various forms of sexual dysfunction and sometimes drugs are used to counteract the effects of psychotropic medications.

When viewing mental health illness and substance use disorders as comorbid conditions there are a number of different pathways to consider such as: mental illness and addiction as separate but contemporaneous conditions; mental illness as a risk factor for addiction; addiction as a risk factor for mental illness and temporary mental illness as a consequence of drug use.

People with mental illness experience more complications from drug use than the general population. A 'dual diagnosis' is when an individual has comorbid mental health and psychiatric diagnoses. 'Dual diagnosis' complicates the prognosis and treatment of each diagnoses though it has been shown that dual treatment of both conditions improves outcomes. Substance use can be an indicator of poor treatment adherence and an increased risk of failure of psychiatric treatment and one should also consider interactions between treatments for both conditions.

In summary it is important to distinguish between substance-induced psychiatric disorders and substance-related psychiatric disorders. Symptoms of psychiatric disorders such as depression, anxiety and psychosis are more the rule than the exception in patients who misuse substances. Treating both the psychiatric and substance disorders improves outcomes for patients. A lot of patients with a 'dual diagnosis' have experienced trauma and stigma so it is important to treat the patient holistically and with empathy and respect to achieve the very best outcomes.

Author: Dr Thileepan Naren
Thileepan is an Addiction Medicine Advanced Trainee and experienced general practitioner with a demonstrated history of working with disadvantaged and marginalized groups.