DUAL DIAGNOSIS IN PRIMARY CARE: Detecting and Treating Both the Addiction and Mental Illness

Psychiatric symptoms are common among individuals with an addiction, and some of these individuals have both a substance use and a psychiatric disorder. These patients have been labeled with a dual diagnosis. Dually diagnosed patients, however, represent a heterogeneous population. There are many different subtypes based on the different combinations of psychiatric and substance use disorders (i.e., schizophrenia and cocaine dependence versus panic disorder and alcohol dependence). Dual diagnosis subtypes also vary according to the relative age of onset, severity, and duration of the substance use and psychiatric disorders. They vary according to their willingness to admit they have a problem and their motivation to seek treatment. Many patients have multiple psychiatric disorders, multiple addictions, and medical illnesses. In general, patients with a dual diagnosis are more difficult to treat than patients who have only one disorder because they require an integrated treatment approach that addresses both problems. Treatment is further complicated by variations within the dual diagnosis subtypes. Dual diagnosis in the primary care setting is common and highlights the complex relationship between addiction and psychopathology. This article emphasizes the need for psychiatric screening of all substance abusers and suggests general strategies for establishing a psychiatric diagnosis. The focus is the assessment and treatment of specific dual diagnosis subtypes, including depression, anxiety, personality disorders, somatoform disorders, eating disorders, attention deficit hyperactivity disorders, and psychotic disorders. Unfortunately, there are few research studies on dual diagnosis in primary care, and the clinical suggestions in this article are generalized from clinical experience and studies in psychiatric and substance abuse treatment settings. The term dual diagnosis can help remind primary care physicians of the common prevalence of both psychiatric and substance use disorders. About 20% of primary care outpatients have a primary or associated mental illness. In the general population, estimates range from approximately 25% to 50% with a lifetime psychiatric disorder to approximately 15% to 25% who currently meet criteria for a psychiatric disorder. Substance use disorders are common among psychiatric patients, and psychiatric disorders are common among patients in substance abuse treatment. The most common psychiatric disorders associated with substance use disorders are depression, anxiety, schizophrenia, and antisocial personality. Of note, 14% of the general population has three or more comorbid disorders (substance abuse and psychiatric disorders). 20,37,43 Often both the substance abuse and the psychiatric problems are hidden from the primary care physician. Any patient presenting with either a psychiatric or a substance use problem should be evaluated for both. Establishing a concurrent psychiatric disorder among active substance abusers can be difficult but is important for appropriate and realistic treatment planning. Patients with psychiatric symptoms should receive a medical evaluation to rule out the possibility that symptoms are caused by a medical illness, medications, or substance abuse. For example, certain medical conditions have high rates of major depression, including stroke, parkinsonism, human immunodeficiency virus (HIV) infection, endocrinopathies, and chronic renal failure. Intoxication or withdrawal (acute or protracted) from alcohol or other drugs as well as chronic use can cause symptoms of depression, mania, anxiety, or psychosis. Screening for substance misuse can be aided with tools such as the CAGE, Trauma scale, MAST (Michigan Alcoholism Screening Test), or AUDIT (Alcohol Use Disorders Identification Test). 30 In all cases, the evaluation for one psychiatric disorder should include an evaluation for other psychiatric disorders, a process that allows the physician to discover related conditions. To cite one example, depressive disorders are associated with personality and anxiety disorders. In the initial evaluations of psychiatric or substance abuse problems, there is much to be gained from contacting a significant other, family member, or friend. Current and lifetime history of symptoms and problems can be elaborated on, including a family history of addictions and psychiatric disorders. Family or friends can provide invaluable information in establishing a diagnosis, evaluating the patient's environment and support system, initiating treatment, and establishing a treatment alliance. The patient's acceptance of a problem and his or her willingness to engage in treatment are important predictors of clinical outcomes. As a result, motivation is an important treatment-matching factor. Whether treated in a primary care or psychiatric setting, many patients with an active substance use disorder (including nicotine dependence) have low motivation to stop using substances. In nonpsychiatric settings, patients with a psychiatric problem often have low motivation to seek treatment, although those with a dual diagnosis may be more likely to complain of psychiatric symptoms. 38 For example, many individuals with clinically significant depression in the community do not seek help because they want to solve the problem themselves, are uncertain where to get help, believe that their problem will spontaneously resolve itself, believe that medical treatment will not help, and think that treatment is too costly or not covered by insurance. 20