The toxic effects of substances can mimic mental illness in ways that can be difficult to distinguish from mental illness. This chapter focuses on symptoms of mental illness that are the result of substance abuse—a condition referred to as “substance-induced mental disorders.”
Cocaine and Amphetamines
Case Studies: Identifying Disorders
As defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision (American Psychiatric Association [APA] 2000) (DSM-IV-TR), substance-induced disorders include:
Substance-induced persisting dementia
Substance-induced persisting amnestic disorder
Substance-induced psychotic disorder
Substance-induced mood disorder
Substance-induced anxiety disorder
Hallucinogen persisting perceptual disorder
Substance-induced sexual dysfunction
Substance-induced sleep disorder
Substance-induced disorders are distinct from independent co-occurring mental disorders in that all or most of the psychiatric symptoms are the direct result of substance use. This is not to state that substance-induced disorders preclude co-occurring mental disorders, only that the specific symptom cluster at a specific point in time is more likely the result of substance use, abuse, intoxication, or withdrawal than of underlying mental illness. A client might even have both independent and substance-induced mental disorders. For example, a client may present with well-established independent and controlled bipolar disorder and alcohol dependence in remission, but the same client could be experiencing amphetamine-induced auditory hallucinations and paranoia from an amphetamine abuse relapse over the last 3 weeks.
Symptoms of substance-induced disorders run the gamut from mild anxiety and depression (these are the most common across all substances) to full-blown manic and other psychotic reactions (much less common). The “teeter-totter principle”—i.e., what goes up must come down—is useful to predict what kind of syndrome or symptoms might be caused by what substances. For example, acute withdrawal symptoms from physiological depressants such as alcohol and benzodiazepines are hyperactivity, elevated blood pressure, agitation, and anxiety (i.e., the shakes). On the other hand, those who “crash” from stimulants are tired, withdrawn, and depressed. Virtually any substance taken in very large quantities over a long enough period can lead to a psychotic state.
Because clients vary greatly in how they respond to both intoxication and withdrawal given the same exposure to the same substance, and also because different substances may be taken at the same time, prediction of any particular substance-related syndrome has its limits. What is most important is to continue to evaluate psychiatric symptoms and their relationship to abstinence or ongoing substance abuse over time. Most substance-induced symptoms begin to improve within hours or days after substance use has stopped. Notable exceptions to this are psychotic symptoms caused by heavy and long-term amphetamine abuse and the dementia (problems with memory, concentration, and problem solving) caused by using substances directly toxic to the brain, which most commonly include alcohol, inhalants like gasoline, and again amphetamines. Following is an overview of the most common classes of substances of abuse and the accompanying psychiatric symptoms seen in intoxication, withdrawal, or chronic use.
In most people, moderate to heavy consumption is associated with euphoria, mood lability, decreased impulse control, and increased social confidence (i.e., getting high). Such symptoms might even appear “hypomanic.” However these often are followed with next-day mild fatigue, nausea, and dysphoria (i.e., a hangover). In a person who has many life stresses, losses, and struggles, which is often the case as addiction to alcohol proceeds, the mood lability and lowered impulse control can lead to increased rates of violence toward others and self. Prolonged drinking increases the incidence of dysphoria, anxiety, and such violence potential. Symptoms of alcohol withdrawal include agitation, anxiety, tremor, malaise, hyperreflexia (exaggeration of reflexes), mild tachycardia (rapid heart beat), increasing blood pressure, sweating, insomnia, nausea or vomiting, and perceptual distortions.
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