SEATTLE -- Methamphetamine-induced psychosis is a challenging condition from both a medical and legal perspective, according to a panel of addiction specialists at the annual meeting of the American Academy of Psychiatry and the Law.
Its is a potent, highly addictive drug that is relatively cheap and easy to make, but "unfortunately, it is also very neurotoxic," said Dr. Mace Beckson, a forensic psychiatrist at the University of California, Los Angeles.
In addition, users of the drug often run into trouble with the law because some of its adverse effects, such as cognitive impairment, paranoia, and psychosis, may be associated with violent behavior. Originally, the drug and the problems associated with it were confined to the western United States and Hawaii, but they have now "spread eastward," he said.
Dr. David Y. Kan, a psychiatrist and substance abuse specialist at the University of California, San Francisco, said that acute methamphetamine psychosis occurs mainly with the use of high doses and that people may become psychotic after just one such incident.
Several risk factors for methamphetamine psychosis have been identified and include preexisting personality disorder (especially antisocial personality disorder), intravenous injection or smoking of the drug, abuse of other substances, previous psychosis, and brain injury.
"The psychosis of methamphetamine tends to be predominantly a positive-symptom psychosis," Dr. Kan noted. Negative symptoms such as alogia, abulia, and the inability to communicate or form thoughts are relatively rare, which helps differentiate it from schizophrenia. "If a person can tell a joke or can laugh at a joke, then they are probably methamphetamine psychotic" and not schizophrenic.
The psychosis typically begins 5-90 hours after starting use of methamphetamine. Users experience sudden hallucinations that are more often visual than auditory and generally in the presence of a clear sensorium. Psychotic users also have paranoid, reality-based delusions and ideas of reference, and are restless and agitated.
"Often, this is one of the few intoxications that includes management from the medical standpoint" with the administration of antipsychotics for the agitation, Dr. Kan noted.
When the psychotic symptoms persist or recur after drug use has stopped, the diagnosis shifts to chronic methamphetamine psychosis. "We make this call all the time, although it's not technically recognized by the DSM-IV," he commented.
Individuals with chronic psychosis often have acute, flashback-type episodes in response to psychosocial stressors, and may experience psychotic symptoms even if they take relatively low doses of methamphetamine. During the flashbacks, plasma levels of norepinephrine and lesser metabolites of dopamine are elevated, and that surge in norepinephrine resembles that in post-traumatic stress disorder, Dr. Kan said. "There may be a different mechanism at play [rather than] traditional dopaminergic models of psychosis."
The association of methamphetamine use with violence is highly controversial because most data come from the criminal justice system. …