Comorbidity in alcohol-use disorders
MELLOS E.
Psychiatrist, Program "ATHINA", 1st Psychiatric Clinic, University of Athens - OKANA

The high rate of co-occurrence of alcohol abuse/dependence problems and other psychiatric disorders is well established. The reasons for co-occurrence, the best methods to differentiate alcohol abuse from psychiatric syndromes, and the best treatments for comorbidity remain open research questions. Nevertheless, a consensus is emerging that comorbid psychiatric and alcohol related disorders present problems and complications that do not occur when the clinical picture is limited to a single disorder.

In the Epidemiologic Catchment Area Study an estimated 45% of individuals with alcohol use disorders had at least one co-occurring psychiatric disorder. In the National Comorbidity Study 78% of alcohol dependent men and 86% of alcohol dependent women met the criteria for a lifetime diagnosis of another psychiatric disorder, including drug dependence. The risk relationship appears to be reciprocal, with psychiatric disorder predicting increased risk of later substance and alcohol use and vice versa.

DSM-IV recognizes at least two types of comorbidity or dual diagnosis. According to DSM-IV criteria a psychiatric disorder is primary or independent if it is not due to the effects from alcohol, implying that psychopathology would precede alcohol abuse or persist during abstinent periods. All other occurrences of psychiatric symptomatology are deemed secondary or alcohol induced, indicating that it is a direct consequence from alcohol use and in many cases symptoms will spontaneously dissipate with abstinence from alcohol. Distinguishing between independent and alcohol-induced psychiatric conditions requires a careful history and examination, because in psychiatry there is no single pathognomonic symptom.

The Epidemiologic Catchment Area Study suggested that more than one third of patients with schizophrenia have a lifetime history of a alcohol use disorder and that almost 4% of alcoholics have also been diagnosed as schizophrenic. Alcohol use disorders have negative consequences for patients with schizophrenia. They are associated with an earlier age of onset, increased relapses, treatment noncompliance, a poorer overall response to antipsychotic medication, more hospitalizations, increased violence and suicide and increased medical costs.

Affective disorders, including major depression and bipolar disorder, are the most common psychiatric comorbidities among alcoholics. According to data from the Epidemiologic Catchment Area Study the prevalence of a lifetime history of major depression is 5% in men and 19% in women who have alcohol dependence. Some prevalence rates are higher, according to the National Comorbidity Study where over 32% of those surveyed with alcohol dependence also had a lifetime history of major depression. Women appear to be at higher risk than men for co-occurring depression and alcoholism. Patients with both depression and an alcohol disorder have multiple problems that stem from depression as well as alcoholism. Findings from clinical studies support the hypothesis that the vast majority of alcohol-dependent individuals did not have an independent mood disorder. Furthermore bipolar disorder is more tied to alcohol abuse/dependence that would be expected by chance alone. Comorbidity of alcoholism and bipolar disorder represents a serious clinical challenge and is associated with sever disabilities, morbidity and a heightened risk for suicide. Several hypotheses have been put forth to explain the relationship. One states that some patients develop alcohol-related problems only in the context of a manic episode and do not show alcohol-related difficulties at other points in their lives.

Lifetime co-occurrence of an alcohol use disorder and an anxiety disorder ranges from 6 to 20% depending on the specific type of anxiety disorder. The relationship between alcohol and anxiety is complex, and making an accurate diagnosis is often difficult because of overlapping symptoms or because of alcohol-induced anxiety.

Eating disorders and alcohol abuse co-occur frequently mainly in treatment settings, posing a significant treatment challenge to clinicians. Alcohol and drug abuse are more often associated with the presence of bulimia nervosa than the restricting subtype of anorexia nervosa.

The development of treatments for dually diagnosed patients, including both pharmacological and psychological treatment approaches, is an exciting and productive area of psychiatric research. Encephalos 2009, 46(2):72-78.

Key words: Alcohol abuse/dependence, comorbidity, schizophrenia, mood disorders, anxiety disorders, eating disorders.