Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
5.2 Comorbidity with depression
- People with depression have high rates of comorbidity with other mental disorders and substance use disorders(17, 68, 119-122).
- Comorbidity in people with depression results in higher levels of impairment(119, 123) and increased severity and recurrence of depression(121, 122, 124).
- Depression and anxiety frequently co-exist(68, 119, 121, 122, 124).
- Psychosocial effects such as stigma, poverty and isolation associated with substance use may contribute to depression; depression also has the potential to predispose people to poverty, isolation and substance use(17).
5.2.1 General management approaches to comorbidity
- Clinicians often find treatment of depression in the presence of substance dependence difficult. It is often unclear what the relationship is between the conditions and whether the depression is brought about by the substance dependence itself, or whether it is a primary depressive disorder, and therefore how best to approach treatment(125).
- Substance use or dependence should not preclude treatment of depression(125).
- In ideal circumstances, the patient should be assessed for persistent depression after a few weeks of abstinence in order to exclude depression related to withdrawal or due to the substance use itself(125).
- Antidepressants are more likely to be effective for primary depression in comparison to substance induced depression(125).
- Improvements in depression may result in short-term reductions in substance use; however, these reductions do not necessarily persist. Therefore, specific interventions for the substance use are also needed to increase the likelihood of long-term abstinence(125).