Co-occurrence of depression and substance abuse often poses diagnostic and therapeutic challenges. This article reviews the prevalence, clinical considerations, and treatment of depression coexisting with alcohol use disorders (AUDs).
Mood and substance use disorders (SUDs) are very common with an estimated lifetime prevalence in the U.S. of 17% for major depression, 4% for bipolar I and II disorders, 13% for alcohol abuse, and 5% for alcohol dependence. 1 Almost all of the associations between disorders of mood or anxiety and drug use were positive and statistically significant in the National Epidemiologic Survey, on Alcohol and Related Conditions (NESARC), which included 43,093 noninstitutionalized patients. 2
There is a reciprocal relationship between depression and alcoholism. Epidemiologic Catchment Area Survey results indicated that baseline symptoms of depression or alcohol abuse increased the risk of developing alcohol dependence or depression. 3 The risk of developing depression were elevated among people with increasing levels of alcohol-induced debility. Conversely, the presence of depressive symptoms increased the chance of developing alcohol dependence. The association between alcohol dependence and depression may be attributable to the depressive effects of ethanol; depression often remits with sobriety. Psychosocial consequences of problem drinking also may contribute to affective illnesses.
Alcohol dependence poses a major depression risk that contributes to higher rates of alcohol use. In people with ethanol dependence, the prevalence of major depressive disorder (MDD) is 21%. 4 People who are alcohol dependent are 4 times more likely than are nondependents to have MDD. Forty-one percent of people who seek treatment for current alcohol abuse have a mood disorder.
The NESARC survey revealed strong associations between depression, substance use, and other psychopathologies. 5 Compared with MDD alone, SUD combined with MDD conferred high vulnerability to additional psychopathology, depressive episodes that were more severe and greater in number, and more suicide attempts.
Depression Clincal Considerations
Depression linked to recent alcohol abuse may not respond well to an antidepressant drug beyond what is achieved with ethanol abstinence. In one study, depressive symptoms were assessed over the course of alcohol-related hospitalizations. 6 Depression was evident in 42% of patients 48 hours after admission, but only 6% remained clinically depressed by week 4 of hospitalization. Therefore, in the treatment of patients hospitalized for alcohol detoxification, it is common to observe them for 1 month before considering antidepressant medication. Mood likely will improve without pharmacotherapy.
However, delaying treatment for depression while a patient is hospitalized for alcohol detoxification presents some difficulties. Many patients do not remain sober during the first month after detoxification. One study found that 65% of patients imbibed alcohol within 2 weeks after discharge. 7 Furthermore, 50% relapsed into heavy drinking during the same period. More than 25% of patients who used alcohol and were diagnosed with substance-induced depression at baseline were reclassified with MDD the next year. 8
Careful clinical assessment is needed after alcohol detoxification. Depression that persists during ethanol abstinence predisposes a patient to relapse into heavy drinking. Therefore, failure to treat depression after alcohol detoxification poses considerable risk. 9 A study of the effect of depression on the return to drinking among patients with alcohol dependence found that depression at entry into inpatient treatment for alcohol dependence predicted a shorter time to first drink. 9 The prognosis for a drinking relapse was worse no matter whether the depression came first or was triggered by the alcohol. Depression does not predict drinking outcomes, but it is associated with a more rapid relapse to ethanol consumption.
Similarly, inpatients with premorbid or substanceinduced depression were more likely to meet the criteria for drug dependence during outpatient follow-up. 10 In addition, patients who developed depression during the first 26 weeks after hospitalization were 3 times more likely than those without depression to relapse into drug dependence during follow-up.
Alcohol dependence may hasten the progression of depression. A study on the prognostic effect of alcoholism on the 10-year course of depression found a deleterious influence of current alcoholism after recovery from depression. 11 Patients with MDD were more likely to transition from being ill to improving if either they were forgoing alcohol or had never abused it. Another investigation verified that alcohol and drug dependence increased perceptions of affective symptomatology. 12
Substance-induced depression also increases the risk for suicide. In 602 patients with substance dependence, depression was classified as occurring before dependence, during abstinence, or during substance use. 13 Depression increased the risk for suicide in 34% of patients
who had already attempted suicide at least once. Compared with depression absent substance