About 7 of every 8 prisons in the nation tested an estimated total of 565,500 inmates for one or more illegal drugs between July 1, 1989, and June 30, 1990. In state facilities, 3.6 per cent of the tests for cocaine, 1.3 per cent for heroin, 2.0 per cent for methamphetamines, and 6.3 per cent for marijuana found evidence of drug use. In federal prisons, 0.4 per cent of the tests for cocaine, 0.4 per cent for heroin, 0.1 per cent for methamphetamines, and 1.1 per cent for marijuana were positive.
This report uses information provided to the Census of State and Federal Adult Correctional Facilities. Data were collected from 957 state prison facilities, 250 state community-based facilities, and 80 federal prisons operating on June 29, 1990. Censuses were also conducted in 1984, 1979, and 1974, but the 1990 census was the first to gather information on drug interdiction practices, drug testing of inmates and staff, and inmate drug treatment programs.
Other findings from the 1990 census include the following:
â€¢ Ninety-eight per cent of state community-based facilities-those in which at least half of the residents may leave the facility daily-tested residents. All federal prisons and 83 per cent of state prisons reported that they tested inmates for drugs.
â€¢ Seventy-six per cent of institutions reported testing inmates for drugs when drug use was suspected. Twenty per cent tested all inmates at least once during confinement.
â€¢ At state confinement facilities 1.4 per cent of tests for cocaine, 1.0 per cent for heroin, 2.3 per cent for methamphetamines, and 5.8 per cent for marijuana indicated drug use.
â€¢ At state community-based facilities 8. 9 per cent of tests for cocaine confirmed the presence of the drug, as did 2.2 per cent for heroin, 1.1 per cent for methamphetamines, and 8.1 per cent for marijuana.
â€¢ State confinement facilities that only tested inmates suspected of drug use had higher positive rates than facilities that tested all or random groups of inmates (6% for cocaine and 14% for marijuana versus 1.5% for cocaine and 5% for marijuana).
â€¢ State and federal facilities used a variety of methods to prevent drugs from being brought into the institution, including questioning, patdowns, clothing exchanges, and body cavity searches.
â€¢ At admission inmates were required to exchange clothing in 88 per cent of the federal prisons and 58 per cent of state prisons; inmates were patted down in 88 per cent of federal prisons and 78 per cent of the state prisons.
â€¢ In the facilities using the most intrusive interdiction technique, body cavity searches, positive drug test results among inmates tested were lower than in facilities using other methods of interdiction.
â€¢ Questioning and search of belongings were widely used for visitors to both federal and state facilities.
â€¢ Federal confinement facilities reported that they could provide drug treatment for an estimated 7,800 inmates; state confinement facilities, for 114,000; and state community-based facilities, for 9,400.
â€¢ Federal facilities were using an estimated 62 per cent of total drug treatment capacity on June 29, 1990; state confinement facilities, 78 per cent; and community-based facilities, 66 per cent.
Interpreting Measures of Drug Testing
Prevalence of drug use in prisons is difficult to estimate. Part of the difficulty occurs with record-keeping and reporting. A drug test determines the presence of a specific drug at a specific level. A single urine sample can be used for a single drug test or for multiple tests for different drugs. Correctional authorities were asked to report the number of tests for each drug and the number of positive tests. However, some authorities may have reported the number of urine samples taken if their records included only those figures.
Other difficulties in estimating the amount of drug use in prison include the following:
â€¢ Prisons differ in the selection of whom to test. Most facilities do not choose inmates for testing using a sample with a known probability of selection: one cannot say that the selected inmates represent all inmates in the institution.
â€¢ Prisons differ in what drugs they test for. Prison authorities may not suspect the use of a drug and not test for it, even though the drug is used in their facility. Other prisons may conduct repeated tests for a drug seldom used.
â€¢ A single urine specimen can have more than one positive drug test from an individual using multiple drugs. Describing positive rates by type of drug will overstate the number of inmates with at least one positive test.
â€¢ Prisons differ in how often they test inmates. Drug testing may be rare in some prisons and frequent in others.
â€¢ Urine tests only detect the presence of most drugs 48 to 72 hours after use, except for PCP and marijuana, which may be detected up to 30 days after use. This varying span, when combined with lack of random sampling, distorts any estimation of overall drug use.
â€¢ Depending on various factors, the presence of methamphetamines may not be distinguished from amphetamines; therefore, the test results for these two drugs should be considered together.
â€¢ Prisons may differ in the types of tests used. Some types are more accurate than others, producing lower numbers of false positives and false negatives. Facilities may or may not perform confirmatory tests, and they were not asked to estimate the number of false positives and false negatives.
This article was based on the Bureau, of Justice Statistics report "Drug Enforcement and Treatment in Prisons, 1990," NCJ-134724. Copies of the complete report are available through the Alaska Justice Statistical Analysis Unit of the Justice Center.