Comorbidity of alcoholism and psychiatric disorders: an overview

Alcohol Research & Health, Spring, 2002 by Ismene L. Petrakis, Gerardo Gonzalez, Robert Rosenheck, John H. Krystal

People with alcohol use disorders often have co-occurring psychiatric disorders, but they frequently do not receive specialized substance abuse treatment that addresses both conditions. Although pharmacological and psychosocial treatments for alcohol use disorders and psychiatric disorders can be integrated to help these patients, relatively few clinical studies have tested these types of treatments. As mental health and substance abuse facilities expand their services for patients with dual disorders, further research is needed to guide the treatment of this patient population. KEY WORDS: AODD (alcohol and other drug dependence); comorbidity; mentally ill; prevalence; health care utilization; drug therapy; antidepressants; serotonin uptake inhibitors; psychosocial treatment method; antipsychotic tranquilizers; 12-step program

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Alcohol abuse and dependence frequently occur with other psychiatric conditions; this dual diagnosis is called comorbidity. Professionals working with comorbid patients face unique and challenging dilemmas about how to provide the best treatment to address both conditions. Despite growing interest in these problems, relatively few clinical studies have tested treatments for this patient population. This review examines the prevalence of alcohol abuse and dependence with other psychiatric disorders and the patterns of treatment among comorbid patients. It also describes how treatment approaches can be integrated for patients with these comorbid disorders and offers suggestions for future directions in treatment research.

RATES OF PSYCHIATRIC DISORDERS IN PATIENTS WITH ALCOHOL USE DISORDERS

The two main U.S. studies that have addressed the epidemiology of comorbidity are the National Comorbidiry Survey (NCS) (Kessler et al. 1996) and the Epidemiologic Catchment Area (ECA) study (Regier et al. 1990). The NCS was a nationally representative household survey of people ages 15-54 conducted in 1990-1991. Diagnoses were based on the results of diagnostic interviews. The ECA study reflected data from the U.S. general population as well as an institutionalized population, using data from the National Institute of Mental Health Epidemiologic Catchment Area Program. A total of 20,291 people ages 18 and older were interviewed between 1980 and 1984.

Alcohol abuse is an alcohol use disorder characterized by continued drinking despite negative consequences and the inability to fulfill responsibilities. Alcohol dependence, also known as alcoholism, is characterized by a craving for alcohol, possible physical dependence on alcohol, an inability to control one's drinking on any given occasion, and an increasing tolerance to alcohol's effects (American Psychiatric Association [APA] 1994). The table shows the prevalence rates of psychiatric disorders among the respondents to the NCS and the ECA study who were diagnosed with alcohol abuse or dependence and a comorbid psychiatric disorder.

Alcohol Abuse

In the NCS, 2.5 percent of the respondents were classified as having abused alcohol but not as having been alcohol dependent during the 12-month period before the survey. In the ECA study, 3.5 percent of respondents were diagnosed as having alcohol abuse at some point in their lifetime. Among respondents to the NCS who had abused alcohol, 12.3 percent also met the criteria for a mood disorder (including major depression and bipolar disorder, characterized by shifts in mood between depression and manic episodes) during the previous year. Of those with comorbid mood disorders, 11.3 percent had major depressive disorder and 0.3 percent had bipolar disorder. (For each category of comorbid disorders, the prevalences of only a few specific disorders are reported. Therefore, the prevalence rates of the specific disorders [e.g., major depressive disorder, bipolar disorder] do not total the rate for the general type [e.g., mood disorders]). Post-traumatic stress disorder (PTSD) was the most frequently occurring anxiet y disorder (i.e., compared with generalized anxiety disorder [GAD] and panic disorder), affecting 5.6 percent of respondents diagnosed as alcohol abusers. The estimated rates of GAD and panic disorder were smaller and similar to each other (1.4 percent and 1.3 percent, respectively). There were no statistically significant associations between alcohol abuse and any of these psychiatric disorders.

The lifetime rates for comorbid schizophrenia were available only from the ECA study. Almost 10 percent of the people diagnosed as alcohol abusers in that study also had a diagnosis of schizophrenia. The odds of having schizophrenia were 1.9 times higher among people who abused alcohol than among those who did not.

Alcohol Dependence

For each of the psychiatric disorders examined, prevalence rates were higher among people diagnosed as alcohol dependent than among alcohol abusers (see table). In the NCS study, 7.2 percent of the survey respondents were diagnosed as alcohol dependent during the 12 months before the survey, and in the ECA study, 7.9 percent of respondents were diagnosed as having been alcohol-dependent at some point in their lifetime. Almost one-third (29.2 percent) of NCS respondents with alcohol dependence had a mood disorder. Alcohol-dependent respondents were 3.9 times more likely to have had major depressive disorder (27.9 percent) during the previous year than those who were not alcohol dependent. Although bipolar disorder was diagnosed in only 1.9 percent of people with alcohol dependence, the odds of having this disorder were 6.3 times greater among alcohol-dependent people compared with others.