Prominent psychotic symptoms (i.e., hallucinationsand/or delusions) determined to be caused by the effects of a psychoactive substance is the primary feature of a substance-induced psychotic disorder. A substance may induce psychotic symptoms during intoxication (while the individual is under the influence of the drug) or during withdrawal (after an individual stops using the drug).
Description
A substance-induced psychotic disorder is subtyped or categorized based on whether the prominent feature is delusions or hallucinations. Delusions are fixed, false beliefs. Hallucinations are seeing, hearing, feeling, tasting, or smelling things that are not there. In addition, the disorder is subtyped based on whether it began during intoxication on a substance or during withdrawal from a substance. A substance-induced psychotic disorder that begins during substance use can last as long as the drug is used. A substance-induced psychotic disorder that begins during withdrawal may first manifest up to four weeks after an individual stops using the substance.
Causes
A substance-induced psychotic disorder, by definition, is directly caused by the effects of drugs including alcohol, medications, and toxins. Psychotic symptoms can result from intoxication on alcohol, amphetamines(and related substances), cannabis (marijuana), cocaine, hallucinogens, inhalants, opioids, phencyclidine (PCP) and related substances, sedatives, hypnotics, anxiolytics, and other or unknown substances. Psychotic symptoms can also result from withdrawal from alcohol, sedatives, hypnotics, anxiolytics, and other or unknown substances.
The speed of onset of psychotic symptoms varies depending on the type of substance. For example, using a lot of cocaine can produce psychotic symptoms within minutes. On the other hand, psychotic symptoms may result from alcohol use only after days or weeks of intensive use.
The type of psychotic symptoms also tends to vary according to the type of substance. For instance, auditory hallucinations (specifically, hearing voices), visual hallucinations, and tactile hallucinations are most common in an alcohol-induced psychotic disorder, whereas persecutory delusions and tactile hallucinations (especially formication) are commonly seen in a cocaine- or amphetamine-induced psychotic disorder.
Symptoms
The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) notes that a diagnosisis made only when the psychotic symptoms are above and beyond what would be expected during intoxication or withdrawal and when the psychotic symptoms are severe. Following are criteria necessary for diagnosis of a substance-induced psychotic disorder as listed in the DSMIV-TR:
Hallucinations and/or delusions develop during, or within one month of, intoxication or withdrawal from a substance or medication known to cause psychotic symptoms.
Psychotic symptoms are not actually part of another psychotic disorder (such as schizophrenia, schizophreniform disorder, schizoaffective disorder) that is not substance induced. For instance, if the psychotic symptoms began prior to substance or medication use, then another psychotic disorder is likely.
Psychotic symptoms do not only occur during delirium.
Demographics
Little is known regarding the demographics of substance-induced psychosis. However, it is clear that substance-induced psychotic disorders occur more commonly in individuals who abuse alcohol or other drugs.
Diagnosis
Diagnosis of a substance-induced psychotic disorder must be differentiated from a psychotic disorder due to a general medical condition. Some medical conditions (such as temporal lobe epilepsy or Huntington's chorea) can produce psychotic symptoms, and, since individuals are likely to be taking medications for these conditions, it can be difficult to determine the cause of the psychotic symptoms. If the symptoms are determined to be due to the medical condition, then a diagnosis of a psychotic disorder due to a general medical condition is warranted.
Substance-induced psychotic disorder also needs to be distinguished from delirium, dementia, primary psychotic disorders, and substance intoxication and withdrawal. While there are no absolute means of determining substance use as a cause, a good patient history that includes careful assessment of onset and course of symptoms, along with that of substance use, is imperative. Often, the patient's testimony is unreliable, necessitating the gathering of information from family, friends, coworkers, employment records, medical records, and the like. Differentiating between substance-induced disorder and a psychiatric disorder may be aided by the following:
Time of onset: If symptoms began prior to substance use, it is most likely a psychiatric disorder.
Substance use patterns: If symptoms persist for three months or longer after substance is discontinued, a psychiatric disorder is probable.
Consistency of symptoms: Symptoms more exaggerated than one would expect with a particular substance type and dose most likely amounts to a psychiatric disorder.
Family history: A family history of mental illness may indicate a psychiatric disorder.
Response to substance abuse treatment: Clients with both psychiatric and substance use disorders often have serious difficulty with traditional substance abuse treatment programs and relapse during or shortly after treatment cessation.
Client's stated reason for substance use: Those with a primary psychiatric diagnosis and secondary substance use disorder will often indicate they "medicate symptoms," for example, drink to dispel auditory hallucinations, use stimulants to combat depression, use depressants to reduce anxiety or soothe a manic phase. While such substance use most often exacerbates the psychotic condition, it does not necessarily mean it is a substance-induced psychotic disorder.
Unfortunately, psychological tests are not always helpful in determining if a psychotic disorder is caused by substance use or is being exacerbated by it. However, evaluations, such as the MMPI-2 MAC-R scale or the Wechsler Memory Scale—Revised, can be useful in making a differential diagnosis.
Treatments
Treatment is determined by the underlying cause and severity of psychotic symptoms. However, treatment of a substance-induced psychotic disorder is often similar to treatment for a primary psychotic disorder such as schizophrenia. Appropriate treatments may include psychiatric hospitalizationand antipsychotic medication.
Prognosis
Psychotic symptoms induced by substance intoxication usually subside once the substance is eliminated. Symptoms persist depending on the half-life of the substances (i.e., how long it takes the before the substance is no longer present in an individual's system). Symptoms, therefore, can persist for hours, days, or weeks after a substance is last used.
Prevention
There is very little documented regarding prevention of substance-induced psychotic disorder. However, abstaining from drugs and alcohol or using these substances only in moderation would clearly reduce the risk of developing this disorder. In addition, taking medication under the supervision of an appropriately trained physician should reduce the likelihood of a medicationinduced psychotic disorder. Finally, reducing one's exposure to toxins would reduce the risk of toxin-induced psychotic disorder.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders.4th edition, text revised. Washington, DC: American Psychiatric Association,2000.
Kaplan, Harold I., M.D., and Benjamin J. Sadock, M.D. Kaplan and Sadock's Synopsis of Psychiatry: Behavioral Sciences, Clinical Psychiatry.8th edition. Baltimore: Williams and Wilkins, 2002.
