To the Editor: In the past decade, methamphetamine abuse has been on the rise throughout the United States +(1, +2). Although methamphetamine is generally taken orally or intravenously, crystal methamphetamine or "ice" is smoked. This manner of admission is highly addictive. It is odorless, difficult to detect, and less expensive and longer lasting than crack. Vaporized crystal methamphetamine, when inhaled, is rapidly absorbed through lung capillaries and has pharmacokinetics similar to intravenous amphetamines. With continued abuse, crystal methamphetamine usually leads to paranoid, often violent, psychotic states accompanied by auditory and tactile hallucinations. Many, but not all, patients improve with abstinence and symptomatic treatment with low-dose neuroleptics. Brain damage to dopamine and 5-hydroxytryptamine receptors from the vasoconstriction and neurotoxicity of methamphetamine has been documented in animals +(3). Our experience in Hawaii has provided some clinical evidence to support this.

While binding sites and cerebral perfusion deficits resulting from cocaine and crack abuse have been mapped out with single photon emission computed tomography (SPECT), identifying focal and long-term perfusion deficits in frontal and temporal lobes +(4–+6), no known study of cerebral perfusion in crystal methamphetamine abusers has been published to date. To assess brain perfusion deficits in crystal methamphetamine abusers, we used SPECT to scan 21 crystal methamphetamine abusers with psychotic symptoms. Scans were read by qualified neuroradiologists who were blind to the diagnoses. Length of crystal methamphetamine abuse ranged from 3 months to 10 years. No patients’ charts showed a history of psychotic diagnosis or symptoms before the use of crystal methamphetamine. Sixteen of the 21 (76%) crystal methamphetamine abusers had focal perfusion deficits distributed in the frontal, parietal, and temporal lobes. A similar cerebral perfusion profile has been described for those who exhibit violent or aggressive behavior +(7). Although our study group size was small, dose and length of exposure appear to be related to the extent of the perfusion deficits. In a few additional crystal methamphetamine abusers with psychotic symptoms, multiple SPECT scans have been done to document deficits over time—even years after crystal methamphetamine has left their bodies.

The "ice age" in Hawaii has shown methamphetamine abuse to be both debilitating and dangerous. Our preliminary findings suggest that crystal methamphetamine abuse leads to short-term and potentially long-term functional abnormalities linked to violence. Further research is needed. Clinical data and SPECT scans on crystal methamphetamine abusers are now being reviewed.