Handbook of the MedicalConsequences of Alcoholand Drug Abuse

also called angel dust or crystal) can produce mild agitation, catatonic rigidity, and possible lack of verbal communication. Higher doses can result in coma, apnea, hypertension, and fatality.

The possibility that PCP produces organic mental impairment was studied

by Carlin and colleagues (1979). PCP abusers who had been abstinent for an average length of 27 months were compared on a number of neuropsychological measures to polydrug users who had never used PCP and to controls who were neither alcohol nor substance abusers. Neuropsychological impairment was demonstrated for six of the 12 PCP users, five of the 12 polydrug users, and none of the controls. Neuropsychological test protocols of the Halstead-Reitan Neuropsychological Test Battery and MMPI were rated on overall level of performance on a scale of 1 to 6. Subjects were matched for age, education, sex, and ethnicity. The authors found that 50 percent of the PCP users demonstrated neuropsychological deficits in the range of mild organic mental impairment.

A comprehensive review by Ellison (1995) documented animal studies that revealed the neurotoxic effects in, and neuronal degeneration of, limbic structures. Increased glucose metabolism in the areas of degeneration was noted. These changes in the limbic circuit with degeneration and alteration in glucose metabolism appeared to be similar to that seen in “some schizophrenics and most Alzheimers patients� (Ellison, 1995, p. 250). Thus, increased glucose utilization and neuronal degeneration from neurotoxicity in the limbic structures is seen as the reason for memory disturbances in schizophrenics, Alzheimers patients, and chronic PCP users. Animal studies have also suggested that PCP is involved in a number of different brain neurotransmitter systems (Sircar and Li, 1994). Compared to the illegal drug studies already discussed, the PCP research seems to most clearly demonstrate its deleterious effects.

Amphetamines and MDMA (Ecstasy) Although amphetamine use can result in neurological findings such as hypertension, stroke, brain hemorrhage, or other neuropathy, neuropsychological findings in human subjects have not been well documented, except in the cases of infant and developmental exposure (Hartman, 1995). With the increase of methamphetamine use in the United States, patients are presenting with chronic psychotic illnesses likely to be related to vasoconstriction and neurotoxicity resulting in brain damage (Buffenstein et al., 1999).

The decision-making abilities of chronic amphetamine abusers were studied by Rogers and others (1999). In a computerized decision-making task, chronic amphetamine abusers tended to exhibit longer response times