Substance misuse in a high security hospital: period prevalence and an evaluation of screening

Illicit drug misuse by people with mental disorder in the community has been associated with increased risk of violence but not tested among inpatients.

To evaluate screening for illicit drugs and determine the period prevalence of use in one high security hospital.

A records study six and 18 months after introduction of random ward urine testing was followed by a true random prospective study. A random sub-sample of these tests was checked in the laboratory.

In the first period there were few tests and patchy recording; during the second, both improved, but testing was not random. In the third period there were 217 tests (65% of those requested) in 33 days; 116 tests requested were not carried out, of which 42 were due to patient refusals. Correlations between dipstick and laboratory results, and research and central recording of tests were high. The rate of drug detection was no higher with true randomization. The hospital's central record was confirmed as a reliable and valid research tool with respect to illicit substances. In the year 2000 the central record showed 12 definite cases of illicit substance use in 153,887 patient days, but some for test refusals.

Random, reliable urine drug testing can be implemented, with generally good cooperation between patients and staff. Contrary to popular belief, in this setting there was little misuse. Further research might test whether current extensive preventive measures are cost effective. The methodology might be applied in less controlled settings to test inpatient violence and substance misuse associations.