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Part I of II: Depression and substance use disorder – a meeting of minds
All too often, when depression and substance-use coincide, assumptions are made that the person is ‘self-medicating’. But this oversimplifies what in reality is a complex inter-relationship that requires careful dissection if a patient’s best interests are to be met. During a symposium organized by the US National Institute on Drug Abuse (NIDA) held on the opening day of the 2016 APA congress, experts described new insights and understandings on these commonly comorbid conditions.
Having depression increases your lifetime risk of succumbing to drug or alcohol misuse. Women are more likely than men to have co-morbid depression and substance use disorder (SUD), and as many as half of all people with depression may consume alcohol or drugs to an extent that could constitute SUD. These are the facts, but do psychiatrists really understand the relationship, and what are the implications for clinical practice?
Sobering facts
According to Professor Edward Nunes, Professor of Psychiatry at Columbia University Medical College, New York, the inter-relationship between depression and SUD needs careful exploration. Playing on the high prevalence of these co-morbidities, particularly in middle-aged female patients, Professor Nunes posed four different case histories to delegates at the APA. Each was “a 46 year old female” with features of depression and SUD – and Professor Nunes challenged his audience to come up with a diagnosis. The point he succeeded in making is that substance use in depression is much more that self-medication of an affective disorder. He urged delegates to consider and investigate the subtle but important differences between substance-induced depression, depression that exists independent of and alongside substance use and the effects of substance-use in inducing depressive symptoms. Only by doing this, he said, is it possible to know how best to manage the patient.
No smoke without fire
Both Professor Nunes and Professor Professor Kathleen Brady, Clinical and Translational Research Director at the South Carolina Clinical and Translational Research Institute, were keen to highlight that when depression and SUD occur together, the association might be explained by the presence of yet another psychiatric disorder. Professor Nunes said ‘where there is smoke, there is fire’ and he suggested that depression plus SUD could also be a signal of a current or past history of conditions like ADHD or PTSD.
Diagnostic dilemmas – don’t lump things together!
Describing co-morbid depression and SUD, Professor Nunes said it is important not to think that substance-induced depression is the same as the depression that may result from the immediate withdrawal of alcohol or drugs. The acid-test is to look at the persistence of depression weeks and months after abstinence from drugs or alcohol. He explained that substance-induced depression is a syndrome that exceeds what would be expected from acute substance withdrawal. After drugs and alcohol have been removed from the frame, persistent depression may then be ‘substance-induced’ or may indicate that there is independent underlying depression.
Only by exploring a patient’s history is it possible to determine if depression is independent of, or precedes, SUD. Even then, the relationships are not simple: having SUD can lead to depression; depression may exist independent of SUD; SUD may be a form of self-medication for depression, or the patient may have underlying risk factors that predispose to both depression and SUD and which need separate and different management.
Important prognostic and treatment implications
Professors Brady and Nunes said that this complexity has served to confound the study of outcomes in patients with these comorbidities, including the outcomes of studies assessing antidepressant therapy in ‘SUD-induced depression’. They explained that in many studies, definitions of SUD-induced depression may have been too rigorous, actually defining patients who had independent major depressive disorder (MDD).
Nevertheless, Professor Brady was keen to stress that although having depression is a major predictor for relapse of SUD, treated-depression helps SUD, and in turn treatment of SUD helps with the remission of depression. She said that current advice is to attempt substance withdrawal or abstinence for around one month, to delineate between SUD-induced depression and MDD, before starting antidepressant therapy, but to treat any severe depression, or depression known to precede SUD, as early as possible.
Every little helps
Professor Brady highlighted the important adjunctive roles of pharmacotherapy and psychotherapy on comorbid depression and SUD. She said that even small antidepressant effect sizes may confer the additional benefit of curbing alcohol or drug consumption. Professor Brady believes that it is also important to maximize non-pharmacological options in patients with these comorbidities, given the modest but clear benefits of CBT in SUDs.
Looking to the future, Professor Brady said that there is increasing interest in studying combinations of antidepressant therapies with drugs designed to support patients with SUDs.
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Our correspondent’s highlights from the symposium are meant as a fair representation of the scientific content presented. The views and opinions expressed on this page do not necessarily reflect those of Lundbeck.