Predicting categories of drugs used by suspected drug-impaired drivers using the Drug Evaluation and Classification Program tests

Figures & data

Table 1. Prediction of drug category from signs and symptoms among DEC evaluations: CNS depressants vs. no-drug cases.

Signs and symptoms	B	SE	Wald’s χ^2 test	OR	95% CI for OR
Being under the care of a doctor or dentist	−1.76	0.53	11.14*	0.17	0.06, 0.48
Not impaired vs. impaired assessment of HGN	−2.84	0.56	26.01*	0.06	0.02, 0.17
Not impaired vs. impaired performance on OLS test	−2.23	0.59	14.23*	0.11	0.04, 0.34
Not impaired vs. impaired performance on WAT test	−2.20	0.67	10.97*	0.11	0.03, 0.41
Slow vs. normal reaction to light	2.79	0.60	21.49*	16.20	5.00, 52.58

* P < .0022.

Table 2. Prediction of drug category from signs and symptoms among DEC evaluations: CNS stimulants vs. no-drug cases.

Signs and symptoms	B	SE	Wald’s χ^2 test	OR	95% CI for OR
High vs. normal mean pulse rate	2.39	0.51	22.08*	10.93	4.03, 29.63
Not impaired vs. impaired performance on OLS test	−2.76	0.58	22.35*	0.06	0.02, 0.20
Slow vs. normal reaction to light	3.13	0.60	26.97*	22.79	7.00, 74.18
Rigid vs. normal muscle tone	1.95	0.60	10.54*	7.04	2.17, 22.87

* P < .0022.

Table 3. Prediction of drug category from signs and symptoms among DEC evaluations: Narcotic analgesics vs. no-drug cases.

Signs and symptoms	B	SE	Wald’s χ^2 test	OR	95% CI for OR
Being under the care of a doctor or dentist	−2.68	0.78	11.75*	0.07	0.02, 0.32
Droopy vs. normal eyelids	2.67	0.78	11.60*	14.38	3.10, 66.66
Constricted vs. normal pupil size in darkness	3.92	1.07	13.58*	50.60	6.28, 407.78
Slow vs. normal reaction to light	2.58	0.80	10.47*	13.21	2.78, 63.09

* P < .0022.

Table 4. Prediction of drug category from signs and symptoms among DEC evaluations: Cannabis vs. no-drug cases.

Signs and symptoms	B	SE	Wald’s χ^2 test	OR	95% CI for OR
Condition of the eyes: Reddening of the conjunctiva vs. normal	2.92	0.71	16.74*	18.49	4.57, 74.79
Bloodshot vs. normal	2.74	0.59	21.34*	15.55	4.85, 49.79
Combination vs. normal	3.13	0.58	28.78*	22.97	7.31, 72.16
Low vs. normal mean pulse rate	2.69	2.38	1.29*	14.77	0.14, 155.96
High vs. normal mean pulse rate	1.55	0.39	15.45*	4.70	2.17, 10.16
Lack of convergence vs. convergence	1.27	0.40	10.35*	3.57	1.64, 7.77
Not impaired vs. impaired performance on OLS test	−1.21	0.40	9.35*	0.30	0.14, 0.65
Absence vs. presence of eyelid tremors	−1.34	0.37	13.10*	0.26	0.13, 0.54

* P < .0022.

Table 5. Contribution of groupings of signs and symptoms in predicting drug category among DEC evaluations.

Groups of signs and symptoms	χ^2	Df
Clinical indicators	887.15*	32
Performance on psychophysical tests	251.09*	12
Appearance and physiological response of the eyes	998.80*	68
Observations and statements by the subject	58.96*	20
Full model	2,078.08*	132

* P < .0001.