Substance-/medication-induced psychotic disorder

[Gregory]

Substance- or medication-induced psychotic disorder is characterized by hallucinations and/or delusions due to the direct effects of a substance or withdrawal from a substance in the absence of delirium.
Episodes of substance-induced psychosis are common in emergency departments and crisis centers. There are many precipitating substances, including alcohol, amphetamines, cannabis, cocaine, hallucinogens, opioids, phencyclidine (PCP), and sedative/hypnotics. To be considered substance-induced psychosis, the hallucinations and delusions should be in excess of those that typically accompany simple substance intoxication or withdrawal, although the patient may also be intoxicated or withdrawing.
Symptoms are often brief, resolving shortly after the causative drug is cleared, but psychosis triggered by amphetamines, cocaine, or PCP may persist for many weeks. Because some young people with prodromal or early-stage schizophrenia use substances that can induce psychosis, it is important to obtain a thorough history, particularly to seek evidence of prior mental symptoms before concluding that acute psychosis is due to substance use.
(See also Introduction to Schizophrenia and Related Disorders.)