Chapter 2 The Problem of Dual Diagnosis

Dual Diagnosis and Comorbidity Dual diagnosis – Describes individuals who meet diagnostic criteria for a mental disorder(s) along with one or more substance use disorders Comorbidity – Combinations of any types of psychiatric disorders that co-occur in the same individual More than half of patients in psychiatric treatment meet criteria for more than one diagnosis

Factors that affect rates of dual diagnosis: – Demographics (e.g., age and sex) Males and those of younger age are more likely to abuse substances – Inpatient or outpatient status and chronicity of illness More severely impaired inpatients (e.g., schizophrenics) are less likely to abuse substances than are patients who are less ill – Setting Hospital emergency rooms reflect higher estimates than other settings Dual Diagnosis: Methodological Issues in Determining Prevalence Rates

Definitions of what constitutes dual diagnosis are far from uniform – Studies often use differing definitions and measures of substance use disorders, making prevalence rates diverse and difficult to compare Dual Diagnosis: Methodological Issues in Determining Prevalence Rates cont.

Methods used to determine psychiatric and substance use diagnoses can influence findings – Research with clinical samples will often employ less- standardized assessments – Assessments measure different substances in their assessments of dual diagnosis Split between the mental health and substance abuse treatment systems impacts dual-diagnosis research Dual Diagnosis: Methodological Issues in Determining Prevalence Rates cont.

High Rates of Dual Diagnosis Exist in community samples – Overall, studies find that a psychiatric diagnosis yields at least double the risk of a lifetime alcohol or drug use disorder Rates of dual diagnosis persist over time Changes in definitions (DSM-5) will impact prevalence rates of dual diagnosis in future research

General Psychiatric Patients Highest rates are among patients with severe mental illnesses – Bipolar disorder 45% have an alcohol use disorder and 39% have a drug use disorder – Schizophrenia or paranoid disorders 42% have an alcohol use disorder and 38% have another substance use disorder Other patient groups – Major depression 33% have an alcohol use disorder and 18% have a drug use disorder – Anxiety disorders 19% have an alcohol use disorder and 11% have another substance use disorder

Dual Diagnosis: Patients With Primary Substance Use Disorders Lifetime and current rates of psychiatric disorders are high (e.g., between 55% and 78%) Treatment-seeking substance abusers show high rates of both major depression and bipolar disorder Comorbid patients showed greater problems at baseline (more disabled, drank more heavily) than did substance-abuse-only patients – Difference persisted at 3-month follow-up

Dual Diagnosis: Impact on Patient Functioning Impacts the severity and course of many disorders, especially among patients with serious mental illnesses – Schizophrenia, bipolar disorder, and recurrent major depression More frequent hospitalizations and more relapses for comorbid substance abusers Poorer overall life functioning – Social stability – Health quality – Life satisfaction

Cognitive functioning – Chronic or sustained substance use can contribute to cognitive impairment and resulting brain dysfunction – Overall, no difference on composite scores of cognitive functioning exist between individuals with schizophrenia with or without an SUD – Significantly more work is needed to understand the specifics of cognitive functioning in dual disorders both with regard to preexisting impairment as well as a sequelae of chronic substance use Dual Diagnosis: Impact on Patient Functioning cont.

Treatment noncompliance – Substance use often interferes with compliance with both behavioral and pharmacological treatments – Linked to poorer outcomes Violence – Substance use and its associated noncompliance with treatment is also linked to greater risk for violence – Risk for violent crime among individuals with bipolar disorder is almost entirely due to substance abuse comorbidity Those with bipolar-only diagnoses show extremely low risk for violent crime Dual Diagnosis: Impact on Patient Functioning cont.

Suicide – Psychiatric inpatients with major depressive disorder at greatest risk for suicide – Those with multiple comorbidities are at even higher risk for suicide than single diagnosis Service utilization and health care cost – Increased rate of treatment seeking – Patients with dual diagnoses had psychiatric treatment costs that were approximately 60% higher than the costs of psychiatrically impaired individuals without substance abuse Dual Diagnosis: Impact on Patient Functioning cont.

Physical illness – Individuals with dual diagnosis show increased risk for HIV and AIDS People with schizophrenia and other severe mental illness are now one of the highest-risk groups – Substance use substantially increases the likelihood of unsafe sex practices and other high- risk behaviors (injection drug use) in those with mental illness Dual Diagnosis: Impact on Patient Functioning cont.

Legal problems – While rates of arrest are high, patients are four times more likely to have encounters with the legal system that do not result in arrest Continued substance abuse over a long-term follow-up period was significantly associated with a greater likelihood of arrest Homelessness – Patients are more likely to live in an unstable housing situation or to be homeless – Those with mental illness and substance abuse are more than 4 times as likely to be homeless than are patients who did not abuse substances Dual Diagnosis: Impact on Patient Functioning cont.

Women – Those with comorbid severe mental illness and substance abuse show: Poorer retention in treatment Elevated levels of anxiety, depression, and medical illness More difficulty engaging in treatment and are underrepresented in treatment overall Higher rates of sexual and physical victimization than the general population Dual Diagnosis: Impact on Patient Functioning cont.

Symptom overlap – Symptoms of many psychiatric disorders overlap with those of substance use disorders For example, DSM lists problems in social functioning as symptoms of both schizophrenia and substance use disorders Criteria counting toward multiple diagnoses can potentially increase comorbidity rates and can make a diagnosis of substance abuse difficult Dual Disorders: Assessment and Diagnosis cont.

Substance-induced disorders may resemble psychiatric disorders – Because symptoms of substance use and withdrawal can resemble psychiatric symptoms, differential diagnosis may be confounded – Incorrect treatment decisions may be made if interventions are aimed at what appear to be acute symptoms of psychiatric disorder but are in fact substance-induced symptoms Dual Disorders: Assessment and Diagnosis

Interpretation of Psychopathology and Treatment Outcome Research The overall result of screening out those with substance use disorders is that there are very few data to inform treatment – Given the significant rates of dual disorders found in clinical samples, such an omission is clearly problematic – It is unclear how well findings will generalize to the larger population of individuals with a particular disorder if patients with dual diagnoses are not included Solutions involve statistical analyses

Theories of Dual Diagnosis Common factors models – Some shared influence is responsible for the development of both psychiatric and substance use disorders (e.g., genetic) – Twin, adoption, and family studies clearly show that both mental illness and substance abuse run in families – Studies of familial transmission for comorbid psychiatric and substance use disorders find little evidence for a common genetic factor – Family history may inspire both dysfunctional family interactions and inheritance of deviant personality traits Borderline personality disorder and substance use disorders

Causal models: Secondary substance use disorder models – Self-medication model Patients with psychiatric disorders use substances to self- medicate and relieve discomfort associated with the primary psychiatric disorder – Social facilitation model Patients with severe mental illness may have fewer opportunities for social interaction, and substance abuse helps the process of social engagement in patients who lack appropriate social and interpersonal skills – Neurobiological mechanisms Neurobiological deficits and abnormalities that provide the basis for different forms of mental illness may also predispose for substance abuse Positive reinforcement Theories of Dual Diagnosis cont.

Causal models: Secondary psychiatric disorder models Substance abuse causes psychopathology Substance-induced psychiatric disorder Chronic alcohol use causes depression, but how? – Considerable life stress that alcohol dependence promotes for the drinker – Pharmacological properties of alcohol as a depressant substance Theories of Dual Diagnosis cont.

Bidirectional models – Suggest that either psychiatric or substance use disorders can increase risk and exacerbate the impact of the other – Alcohol and anxiety interact to produce an exacerbation of both anxiety symptoms and drinking – Feed-forward cycle Drinking is promoted by the short-term, anxiety-reducing effects of alcohol At the same time, anxiety symptoms are worsened by heavy drinking, leading to continued drinking in response to these worsened anxiety symptoms Theories of Dual Diagnosis cont.