Substance-Induced Psychotic Disorder. A large number of toxic or psychoactive substances can cause psychotic reactions. Such substance-induced psychosis can occur in multiple ways. First, people may inadvertently ingest toxic substances by accident, either because they don't know any better (as is the case when a child eats lead paint chips, or mercury in tuna fish), or by mistake (such as when someone eats a poison mushroom they thought was safe, or gets food poisoning from mishandled food). Alternatively, people may take too much of a legitimately prescribed medicine, medicines may interact in unforeseen ways, or doctors may miscalculate the effects of medicines they prescribe. Finally, people may overdose on recreational drugs they commonly use (such as cocaine), or become dependent on drugs or alcohol and experience psychotic symptoms while in withdrawal from those substances. While the substance induced psychosis is triggered and then sustained by intoxication or withdrawal, its effects can continue long after intoxication or withdrawal has ended.
Drugs of abuse that can cause psychosis include alcohol, amphetamines, marijuana, cocaine, hallucinogens, inhalants, opioids, and sedative-hypnotics, including medicines that are sometimes used to treat anxiety.
Common over-the-counter and doctor-prescribed medications that can cause psychosis include anesthetics (knock-out drugs), analgesics (pain-relievers), anticholinergic agents, anticonvulsants, antihistamines, cardiovascular (heart) medications, antimicrobial medications, antiparkinsonian medications, chemotherapeutic agents, corticosteroids (steroids), gastrointestinal medications, muscle relaxants, nonsteroidal anti-inflammatory medications (NSAIDS like ibuprophin), and anti-depressants.
Environmental toxins reported to induce psychotic symptoms include anticholinesterase, organophosphate insecticides, nerve gases, carbon monoxide (car exhaust), carbon dioxide, and volatile substances such as fuel or paint.
The following diagnostic criteria must be met before a diagnosis of Substance-Induced Psychotic Disorder is warranted, according to the DSM-IV-TR:
A) Prominent hallucinations or delusions
B) There is evidence from the history, physical examination, or laboratory findings of either (1) or (2):
1. the symptoms in Criterion A developed during, or within a month of, substance intoxication or withdrawal
2. medication use is etiologically related to the disturbance
C) The disturbance is not better accounted for by a Psychotic Disorder that is not substance induced. Evidence that the symptoms are better accounted for by a Psychotic Disorder that is not substance induced might include the following: the symptoms precede the onset of the substance use (or medication use); the symptoms persist for a substantial period of time (e.g., about a month) after the cessation of acute withdrawal or severe intoxication, or are substantially in excess of what would be expected given the type or amount of the substance used or the duration of use; or there is other evidence that suggests the existence of an independent non-substance induced Psychotic Disorder (e.g., a history of recurrent non-substance-related episodes)
D) The disturbance does not occur exclusively during the course of a delirium.