Drug or toxin exposure
OTC drugs and supplements, prescription drugs, and recreational drugs may cause psychosis and other psychiatric symptoms. Examples of OTC drugs that may cause psychosis include:
- Medications containing phenylpropanolamine.
Psychosis usually occurs with chronic use of these drugs or very high doses. Ephedra-containing herbal supplements, such as ma huang, can also trigger psychosis. Other kinds of centrally acting herbal supplements are also available, but it is unknown whether these can trigger psychosis.
Prescription drugs that can trigger psychosis include:
- Dopamine agonists
- Adrenergics (stimulants, propranolol, and clonidine)
- Thyroid hormones.
Psychosis is a rare and relatively idiosyncratic adverse effect of many other medications. These include isotretinoin, indometacin, several antibiotics, and antiviral drugs.
Psychosis may be induced by intoxication with recreational drugs, such as:
- Inhalants (solvents, aerosols, gases, nitrites).
Cannabis use is an environmental risk factor for development of a persistent psychotic disorder. This occurs in a dose-related fashion, increasing the risk by 2 to 6 times for patients without other risk factors. Cannabis use by age 15 years has been shown to increase the risk of developing schizophreniform disorder (odds ratio 1.95).Cannabis intoxication can also cause a psychosis of short duration. Paradoxically, patients with psychotic disorders may report that acute use is associated with reduction of psychosis severity or of anxiety. Some studies report improvement in negative symptoms. However, there is a clear relationship between cannabis use and psychotic relapse.
Withdrawal syndromes from benzodiazepines, barbiturates, and alcohol may also include psychosis. This may be a presenting sign.
Heavy metal exposure causes a wide range of psychiatric and physical (cardiovascular, renal, reproductive, GI, neurological) sequelae. The most common heavy metals responsible for toxic exposures in the US are arsenic, mercury, and lead. Any of these can cause psychosis as a rare symptom.
Continue reading “Assessment of psychosis”