The autopsy reports for cases that occurred in 1991 were also reviewed by three independent forensic pathologists, who were asked to determine the role of methadone in the death. In addition, the study documented Harris County methadone maintenance treatment program enrollment for each decedent. The researchers identified 91 decedents in whom methadone was detected at the time of death, with the largest number of cases occurring in 1991 (n=27). Other substances, including alcohol, were detected in 85 percent of the cases. The Harris County Medical Examiner attributed 11 of the deaths to methadone toxicity. No more than three cases per year from 1987 through 1992 were attributed to methadone toxicity. In contrast, 34 deaths were attributed to polydrug toxicity, the largest number occurring in 1991 (n=11). There was significant agreement between the results of the independent review and the opinions of the Harris County Medical Examiner. Only 20 percent of the decedents were found to have been enrolled in a Harris County methadone maintenance treatment program at the time of death. Four people died of drug toxicity shortly after enrolling in a methadone maintenance treatment program. The study found an increase in the number of deaths that occurred in Harris County, Texas, in 1991 in which methadone was detected. It also found that methadone blood levels were higher among decedents identified for 1991 and 1992 than among those identified in the previous years studied; however, the researchers did not find evidence that the cause of these deaths could be attributed solely to methadone toxicity. Instead, for all years studied, the use of multiple drugs was the leading cause of death among people in whom methadone was detected. This finding points out the difficulties involved in determining the role of methadone as a cause of death. 6 tables, 1 figure, and 37 references