Appendix 4.

Performance of Substance Use Screens for Identifying Any Symptom of Alcohol, Cannabis, or Other Illicit Drug Use Disorder

	Age 12 to 15 Years		Age 16 to 17 Years		Age 18 to 20 Years
	N = 79,170		N = 42,356		N = 48,460
	Se	Sp	Se	Sp	Se	Sp
Alcohol
≥1 day	1.00	0.87	1.00	0.63	1.00	0.46
≥2 days	1.00	0.90	1.00	0.69	1.00	0.50
≥3 days	1.00	0.92	1.00	0.73	1.00	0.54
≥12 days	0.84	0.96	0.89	0.88	0.94	0.72
≥52 days	0.40	0.99	0.48	0.96	0.65	0.88
≥270 days	0.02	1.00	0.02	1.00	0.03	1.00
AUC (SE)	0.98 (0.0003)		0.93 (0.0006)^*		0.88 (0.0007)^*^†
Cannabis
≥1 day	1.00	0.96	1.00	0.86	1.00	0.80
≥2 days	1.00	0.97	1.00	0.88	1.00	0.83
≥3 days	0.99	0.97	1.00	0.90	1.00	0.85
≥12 days	0.90	0.99	0.94	0.95	0.96	0.92
≥52 days	0.61	0.99	0.71	0.98	0.80	0.96
≥270 days	0.12	1.00	0.20	1.00	0.31	0.99
AUC (SE)	0.99 (0.0002)		0.97 (0.0004)^*		0.96 (0.0004)^*^†
Other Illicit Drugs
≥1 day	1.00	0.94	1.00	0.90	1.00	0.87
≥2 days	0.92	0.96	0.95	0.93	0.97	0.89
≥3 days	0.88	0.96	0.90	0.94	0.94	0.91
≥12 days	0.69	0.97	0.71	0.96	0.76	0.95
≥52 days	0.40	0.99	0.44	0.98	0.52	0.98
≥270 days	0.08	1.00	0.13	1.00	0.16	1.00
AUC (SE)	0.98 (0.0003)		0.97 (0.0004)^*		0.97 (0.0004)^*^†

Notes: Se = Sensitivity; Sp = Specificity; AUC = Area under Receiver Operating Characteristic (ROC) Curve for any symptom of DSM-IV Alcohol, Cannabis, or Other Drug Use Disorders; Se, sensitivity; Sp, specificity. Bolded screening cut-points are shown that have high values of sensitivity and specificity and minimize the number of different age- and substance-specific cut-points.
Frequency is coded as days of use in the past year.
χ² test for independence (relative to age 12 to 15 years),
↵* P < .0001.
χ² test for independence (comparing 16–17- and 18–20-year-olds),
↵† P < .0001.