Laboratory Validation Study of Drug Evaluation and Classification Program: Alprazolam, d-Amphetamine, Codeine, and Marijuana

Abstract

The Drug Evaluation and Classification (DEC) program is used by police agencies to identify drivers impaired because of drug use and to determine the class(es) of drug causing the impairment. The primary goal of this study was to determine the validity of the DEC evaluation in predicting whether research volunteers were administered alprazolam, d-amphetamine, codeine, or marijuana. A secondary goal was to determine the accuracy of Drug Recognition Examiners (DREs) in detecting if subjects were dosed with these drugs. Community volunteers (n = 48) were administered alprazolam (0, 1, 2 mg), d-amphetamine (0, 12.5, 25 mg), codeine (0, 60, 120 mg), or marijuana (0, 3.58% THC) in a double-blind, randomized, between-subject design. A single drug dose or placebo was administered at each experimental session, and blood samples were obtained before and after dosing. With the exception of marijuana, plasma drug concentration was at or near maximum during the DEC evaluation. The ability of the DEC evaluation to predict the intake of alprazolam, d-amphetamine, codeine, or marijuana was optimal when using 2-7 variables from the evaluation. DREs' decisions of impairment were consistent with the administration of any active drug in 76% of cases, and their drug class decisions were consistent with toxicology in 32% of cases, according to standards of the International Association of Chiefs of Police. These findings suggest that the DEC evaluation can be used to predict accurately acute administration of alprazolam, d-amphetamine, codeine, and marijuana and that predictions of drug use may be improved by focusing on a subset of variables.

An evaluation of the sensitivity of the standardised field sobriety tests to detect the presence of amphetamine

“…Although not significant, some improvements on the OLS test were observed in the amphetamine conditions. This is consistent with previous research where Heishman et al (1998) found that a decrease in errors on the OLS test was the third best predictor for the presence of dexamphetamine, indicating that the OLS test may not be an appropriate measure of drug presence.…”

“…This is consistent with previous research that has reported improvements on the OLS test after the administration of dexamphetamine (Heishman et al 1998).…”

“…However, the extremely low percentage of participants correctly identified with the presence of a drug is consistent with previous research on amphetamines that have highlighted that the stimulant drug class is notably difficult to detect. Heishman et al (1998) reported that the majority of subjects dosed with dexamphetamine were classified as 'not impaired' by the Drug Recognition Examiners (DREs), and that in only 2% of cases where dexamphetamine was administered the classification was correct. Furthermore, the DREs classified subjects as dosed with other drugs more frequently than with the amphetamine dose administered.…”

Impairment related to blood amphetamine and/or methamphetamine concentrations in suspected drugged drivers

“…The suspected drivers in the present study were mostly apprehended due to conspicuous driving or involvement in traffic accidents, indicating poor driving performance. This was reflected in a high percentage of the drivers being judged impaired compared to experimental studies (Heishman et al, 1998;Silber et al, 2005b). Some drivers having taken amphetamines may not have been apprehended due to a lower degree of impairment.…”

“…Such doses give rise to a C max about 0.10-0.15 mg/l (Silber et al, 2005a). In most of these studies no relationship between impairment and blood amphetamines concentrations or the doses of amphetamines taken has been found (Angrist et al, 1987;Asghar et al, 2003;Brauer et al, 1996;Evans et al, 1976;Heishman et al, 1998;Perez-Reyes et al, 1992;Pickworth et al, 1997;Silber et al, 2005b;Slattum et al, 1996). In real-life settings doses taken are commonly much higher (50-300 mg or more), and are often taken intravenously in binges.…”