Identifying Problematic Substance Use in a National Sample of Adolescents Using Frequency Questions

Laura J. Chavez; Katharine A. Bradley; Gwen T. Lapham; Thomas M. Wickizer; Deena J. Chisolm

doi:10.3122/jabfm.2019.04.180284

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Appendix 2.
Receiver Operating Characteristic (ROC) Curves for Tobacco Dependence, Alcohol Use Disorder, Cannabis Use Disorder, and Other Illicit Drug Use Disorder. AUD, alcohol use disorders; CUD, cannabis use disorders; DUD, drug use disorders.

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Table 1.

Adolescent Sample Characteristics, by Age Group

	Age 12 to 15 Years N = 79,170		Age 16 to 17 Years N = 42,356		Age 18 to 20 Years N = 48,460		Total N = 169,986
	N	(%)	N	(%)	N	(%)	N	(%)
Gender
Males	40,375	(51.2)	21,531	(50.9)	23,901	(51.7)	85,807	(51.2)
Females	38,795	(48.8)	20,825	(49.1)	24,559	(48.3)	84,179	(48.7)
Race/ethnicity
White Non-Hispanic	45,509	(56.1)	24,450	(57.1)	27,670	(56.7)	97,629	(56.5)
Black Non-Hispanic	10,543	(14.2)	5998	(14.8)	6863	(14.5)	23,404	(14.5)
Hispanic	15,053	(21.5)	7762	(20.2)	9180	(20.8)	31,995	(21.0)
Asian	3027	(4.9)	1644	(5.0)	2120	(5.1)	6791	(5.0)
Other	5038	(3.3)	2502	(2.9)	2627	(2.7)	10,167	(3.0)
Criterion Standards
Tobacco Dependence	999	(1.1)	2588	(5.2)	6250	(11.8)	9837	(5.8)
AUD	1,781	(2.1)	3314	(7.3)	6490	(13.1)	11,585	(7.1)
Any AUD Symptom	3796	(4.5)	7264	(16.5)	14,094	(28.8)	25,154	(15.7)
CUD	1509	(1.7)	2733	(6.1)	3324	(6.9)	7566	(4.5)
Any CUD Symptom	2892	(3.4)	5727	(12.9)	8534	(17.8)	17,153	(10.5)
DUD	976	(1.1)	1004	(2.3)	1483	(3.0)	3463	(2.0)
Any DUD Symptom	2114	(2.5)	2043	(4.7)	2890	(5.8)	7047	(4.2)

AUD, alcohol use disorder; CUD, cannabis use disorder; DUD, other illicit drug use disorder.
Ns are unweighted, proportions are weighted to account for complex survey design.
χ² test comparing Criterion Standards across age groups all P < .001.

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Table 2.

Performance of Substance Use Screens for Identifying Tobacco Dependence and Alcohol, Cannabis, and Other Illicit Drug Use Disorder

	Age 12 to 15 Years N = 79,170		Age 16 to 17 Years N = 42,356		Age 18 to 20 Years N = 48,460
	Se	Sp	Se	Sp	Se	Sp
Smoking^*
≥1 day	1.00	0.97	1.00	0.90	1.00	0.79
≥2 days	0.91	0.98	0.96	0.92	0.97	0.82
≥4 days	0.81	0.99	0.89	0.94	0.94	0.86
≥25 days	0.48	1.00	0.68	0.98	0.80	0.95
AUC (SE)	0.99 (0.0002)		0.98 (0.0003)^‡		0.96 (0.0004)^{^‡^§}
Alcohol^†
≥1 day	1.00	0.85	1.00	0.57	1.00	0.38
≥2 days	1.00	0.88	1.00	0.62	1.00	0.41
≥3 days	1.00	0.90	1.00	0.66	1.00	0.44
≥12 days	0.88	0.95	0.92	0.80	0.96	0.60
≥52 days	0.49	0.98	0.58	0.92	0.73	0.79
≥270 days	0.04	1.00	0.03	1.00	0.04	0.99
AUC (SE)	0.97 (0.0004)		0.91 (0.0008)^‡		0.84 (0.0010)^{^‡^§}
Cannabis^†
≥1 day	1.00	0.94	1.00	0.79	1.00	0.71
≥2 days	1.00	0.95	1.00	0.82	1.00	0.73
≥3 days	1.00	0.96	1.00	0.83	1.00	0.75
≥12 days	0.93	0.97	0.95	0.88	0.97	0.81
≥52 days	0.66	0.99	0.74	0.93	0.83	0.87
≥270 days	0.14	1.00	0.20	0.98	0.36	0.96
AUC (SE)	0.99 (0.0002)		0.95 (0.0006)^‡		0.93 (0.0007)^{^‡^§}
Other Illicit Drugs^†
≥1 day	1.00	0.93	1.00	0.88	1.00	0.84
≥2 days	0.95	0.94	0.97	0.90	0.98	0.87
≥3 days	0.92	0.95	0.93	0.92	0.96	0.88
≥12 days	0.75	0.97	0.80	0.95	0.85	0.93
≥52 days	0.48	0.98	0.57	0.98	0.64	0.97
≥270 days	0.14	1.00	0.19	1.00	0.26	1.00
AUC (SE)	0.98 (0.0004)		0.97 (0.0005)^‡		0.97 (0.0005)^{^‡^§}

AUC, Area under Receiver Operating Characteristic (ROC) Curve for Tobacco Dependence (Nicotine Dependence Syndrome Scale/Fagerström Test of Nicotine Dependence) or 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 month.
↵† 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.

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Table 3.

Single-Item Screens for Identifying Substance Use Disorder (or Tobacco Dependence) in Adolescents (Age 12 to 20 years)

Screening Questions	Screening Cut-Points for Positive Screen
1. During the past 30 days, on how many days did you smoke part or all of a cigarette?	≥1 day all age groups
2. On how many days in the past 12 months did you drink an alcoholic beverage?	≥3 days for ages 12 to 15 years
	≥12 days if older
3. On how many days in the past 12 months did you use marijuana or hashish?	≥3 days for ages 12 to 15 years
	≥12 days if older
4. On how many days in the past 12 months did you use cocaine, crack, heroin, hallucinogens, inhalants, or prescription medications including pain relievers, tranquilizers, stimulants, or sedatives that were not prescribed for you or that you took only for the feeling that it caused.	≥1 day all age groups

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.

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Appendix 1.

Prevalence of Criterion Standards, by Age Group and Gender

	Females						Males
	Age 12 to 15 Years		Age 16 to 17 Years		Age 18 to 20 Years		Age 12 to 15 Years		Age 16 to 17 Years		Age 18 to 20 Years
	N = 38,795		N = 20,825		N = 24,559		N = 40,375		N = 21,531		N = 23,901
	N	(%)	N	(%)	N	(%)	N	(%)	N	(%)	N	(%)
Tobacco Dependence	507	(1.2)	1200	(4.9)^*	2891	(10.5)^†	492	(1.1)	1388	(5.6)	3359	(13.1)
AUD	1068	(2.6)^†	1688	(7.4)	2822	(11.2)^†	713	(1.6)	1626	(7.1)	3668	(14.9)
Any AUD Symptom	2107	(5.1)^†	3637	(16.6)	6383	(25.7)^†	1,689	(3.9)	3627	(16.4)	7711	(31.6)
CUD	773	(1.8)	1146	(5.1)^†	1220	(5.1)^†	736	(1.7)	1587	(7.2)	2104	(8.6)
Any CUD Symptom	1349	(3.1)^*	2358	(10.6)^†	3260	(13.5)^†	1,543	(3.6)	3369	(15.2)	5274	(21.9)
DUD	624	(1.4)^†	554	(2.5)^*	680	(2.7)^†	352	(0.8)	450	(2.0)	803	(3.3)
Any DUD Symptom	1278	(3.0)^†	1089	(5.1)^*	1329	(5.4)^†	836	(2.1)	954	(4.3)	1561	(6.3)

AUD, alcohol use disorder; CUD, cannabis use disorder; DUD, other illicit drug use disorder.
Ns are unweighted, proportions are weighted to account for complex survey design.
χ² test for independence (comparing females and males, within same age group),
↵* P < .01,
↵† P < .0001.

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Appendix 3.

Performance of Substance Use Screens for Identifying Tobacco Dependence and Alcohol, Cannabis, and Other Illicit Drug Use Disorders, by Age and Gender

	Males						Females
	12 to 15 Years		16 to 17 Years		18 to 20 Years		12 to 15 Years		16 to 17 Years		18 to 20 Years
	Se	Sp	Se	Sp	Se	Sp	Se	Sp	Se	Sp	Se	Sp
Smoking^*
≥1 day	1.00	0.98	1.00	0.90	1.00	0.76	1.00	0.97	1.00	0.91	1.00	0.83
≥2 days	0.89	0.98	0.95	0.92	0.97	0.80	0.93	0.98	0.96	0.93	0.98	0.85
≥4 days	0.79	0.99	0.88	0.94	0.94	0.83	0.83	0.99	0.91	0.95	0.95	0.88
≥25 days	0.45	1.00	0.65	0.98	0.77	0.94	0.51	1.00	0.72	0.99	0.84	0.96
AUC (SE)	0.99	(0.0002)	0.97	(0.0005)^‡	0.95	(0.0007)^‡	0.99	(0.0002)	0.98	(0.0005)	0.96	(0.006)
Alcohol^†
≥1 day	1.00	0.85	1.00	0.58	1.00	0.37	1.00	0.84	1.00	0.56	1.00	0.38
≥2 days	1.00	0.88	1.00	0.62	1.00	0.41	1.00	0.87	1.00	0.61	1.00	0.42
≥3 days	1.00	0.90	1.00	0.66	1.00	0.44	1.00	0.89	1.00	0.66	1.00	0.45
≥12 days	0.89	0.95	0.94	0.80	0.97	0.58	0.88	0.95	0.91	0.81	0.95	0.62
≥52 days	0.50	0.98	0.58	0.92	0.75	0.77	0.48	0.98	0.57	0.92	0.71	0.82
≥270 days	0.03	1.00	0.03	1.00	0.05	0.99	0.04	1.00	0.03	1.00	0.03	0.99
AUC (SE)	0.97	(0.0008)	0.90	(0.0012)	0.82	(0.0014)^‡	0.97	(0.0006)	0.90	(0.0012)	0.83	(0.0015)
Cannabis^†
≥1 day	1.00	0.94	1.00	0.78	1.00	0.68	1.00	0.94	1.00	0.81	1.00	0.74
≥2 days	0.99	0.95	1.00	0.80	1.00	0.70	1.00	0.95	1.00	0.83	1.00	0.76
≥3 days	0.99	0.95	1.00	0.82	1.00	0.72	1.00	0.96	1.00	0.85	0.99	0.78
≥12 days	0.93	0.97	0.96	0.87	0.98	0.78	0.93	0.98	0.94	0.90	0.96	0.85
≥52 days	0.66	0.98	0.78	0.92	0.85	0.84	0.66	0.99	0.67	0.94	0.79	0.90
≥270 days	0.16	1.00	0.22	0.98	0.39	0.95	0.13	1.00	0.19	0.99	0.32	0.98
AUC (SE)	0.98	(0.0004)^‡	0.94	(0.0009)^‡	0.91	(0.0010)^‡	0.99	(0.0004)	0.95	(0.0008)	0.94	(0.0009)
Other Illicit Drugs^†
≥1 day	1.00	0.94	1.00	0.88	1.00	0.82	1.00	0.92	1.00	0.88	1.00	0.86
≥2 days	0.94	0.95	0.96	0.90	0.98	0.85	0.96	0.94	0.97	0.91	0.98	0.88
≥3 days	0.92	0.95	0.92	0.92	0.96	0.87	0.92	0.94	0.94	0.92	0.96	0.90
≥12 days	0.67	0.97	0.80	0.95	0.86	0.92	0.80	0.96	0.80	0.95	0.86	0.94
≥52 days	0.45	0.98	0.56	0.98	0.65	0.96	0.50	0.98	0.58	0.98	0.65	0.97
≥270 days	0.13	1.00	0.18	1.00	0.27	1.00	0.15	1.00	0.21	1.00	0.24	1.00
AUC (SE)	0.98	(0.0005)	0.97	(0.0008)	0.96	(0.0008)^‡	0.98	(0.0005)	0.97	(0.0007)	0.97	(0.0007)

AUC, area under receiver operating characteristic (ROC) curve for tobacco dependence (Nicotine Dependence Syndrome Scale/Fagerström Test of Nicotine Dependence) or 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 month.
↵† Frequency is coded as days of use in the past year.
χ² test for independence (within age group, male relative to female adolescents),
↵‡ P < .0001.

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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.

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Appendix 5.

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

	Males						Females
	12 to 15 Years		16 to 17 Years		18 to 20 Years		12 to 15 Years		16 to 17 Years		18 to 20 Years
	Se	Sp	Se	Sp	Se	Sp	Se	Sp	Se	Sp	Se	Sp
Alcohol
≥1 day	1.00	0.87	1.00	0.64	1.00	0.47	1.00	0.86	1.00	0.62	1.00	0.45
≥2 days	1.00	0.91	1.00	0.69	1.00	0.50	1.00	0.89	1.00	0.68	1.00	0.50
≥3 days	1.00	0.93	1.00	0.74	1.00	0.54	1.00	0.92	1.00	0.73	1.00	0.54
≥12 days	0.85	0.97	0.91	0.87	0.95	0.71	0.83	0.96	0.86	0.88	0.93	0.73
≥52 days	0.40	0.99	0.49	0.95	0.68	0.87	0.39	0.99	0.47	0.96	0.62	0.89
≥270 days	0.02	1.00	0.03	1.00	0.04	1.00	0.02	1.00	0.02	1.00	0.03	1.00
AUC (SE)	0.98	(0.0004)^†	0.93	(0.0009)	0.86	(0.0011)	0.97	(0.0004)	0.93	(0.0009)	0.86	(0.0011)
Cannabis
≥1 day	1.00	0.96	1.00	0.85	1.00	0.80	1.00	0.96	1.00	0.86	1.00	0.81
≥2 days	1.00	0.97	1.00	0.88	1.00	0.82	0.99	0.97	1.00	0.89	1.00	0.83
≥3 days	1.00	0.97	1.00	0.89	1.00	0.84	0.99	0.97	1.00	0.90	1.00	0.85
≥12 days	0.91	0.99	0.95	0.94	0.97	0.91	0.89	0.99	0.92	0.95	0.94	0.92
≥52 days	0.62	0.99	0.74	0.97	0.82	0.95	0.60	1.00	0.65	0.98	0.76	0.96
≥270 days	0.13	1.00	0.22	1.00	0.34	0.99	0.11	1.00	0.16	1.00	0.26	1.00
AUC (SE)	0.99	(0.0002)	0.98	(0.0004)	0.97	(0.0005)	0.99	(0.0002)	0.98	(0.0004)	0.97	(0.0005)
Other Illicit Drugs
≥1 day	1.00	0.95	1.00	0.90	1.00	0.85	1.00	0.94	1.00	0.91	1.00	0.88
≥2 days	0.92	0.96	0.95	0.92	0.97	0.88	0.92	0.95	0.94	0.93	0.97	0.91
≥3 days	0.88	0.96	0.90	0.93	0.94	0.90	0.87	0.96	0.90	0.94	0.94	0.92
≥12 days	0.65	0.98	0.72	0.96	0.77	0.94	0.72	0.97	0.71	0.97	0.76	0.96
≥52 days	0.37	0.99	0.43	0.98	0.52	0.98	0.42	0.99	0.45	0.99	0.52	0.98
≥270 days	0.07	1.00	0.11	1.00	0.17	1.00	0.09	1.00	0.14	1.00	0.15	1.00
AUC (SE)	0.98	(0.0004)^*	0.97	(0.0006)	0.96	(0.0006)^†	0.98	(0.0004)	0.97	(0.0005)	0.97	(0.0005)

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 (within age group, male relative to female adolescents),
↵* P < .01,
↵† P < .0001.

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Appendix 6.

Characteristics of Outpatient Subgroup (2013 to 2014)

	Outpatients
	N = 31,505
	N	(%)
Gender
Males	14,941	(47.8)
Females	16,564	(52.2)
Age, years
12 to 15	14,699	(41.9)
16 to 17	8353	(23.7)
18 to 20	8453	(34.4)
Race/ethnicity
White Non-Hispanic	17,808	(55.5)
Black Non-Hispanic	4254	(13.8)
Hispanic	6079	(21.7)
Asian	1402	(5.6)
Other	1962	(3.4)
Criterion Standards
Tobacco Dependence	1313	(4.3)
AUD	1683	(5.8)
Any AUD symptom	3991	(14.0)
CUD	1270	(4.0)
Any CUD Symptom	3173	(10.5)
DUD	505	(1.6)
Any DUD Symptom	1106	(3.5)

AUD, alcohol use disorder; CUD, cannabis use disorder; DUD, other illicit drug use disorder.

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Appendix 7.

Performance of Substance Use Screens for Identifying Tobacco Dependence and Alcohol, Cannabis, and Other Illicit Drug Use Disorder among Outpatient Subgroup (2013 to 2014).

	Age 12 to 15 Years		Age 16 to 17 Years		Age 18 to 20 Years
	N = 14,699		N = 8353		N = 8453
	Se	Sp	Se	Sp	Se	Sp
Smoking^*
≥1 day	1.00	0.98	1.00	0.93	1.00	0.83
≥2 days	0.86	0.99	0.92	0.94	0.96	0.86
≥4 days	0.76	0.99	0.82	0.96	0.94	0.89
≥25 days	0.48	1.00	0.64	0.99	0.77	0.97
AUC (SE)	0.99 (0.0003)		0.98 (0.0007)^‡		0.97 (0.0009)^{^‡^§}
Alcohol^†
≥1 day	1.00	0.86	1.00	0.57	1.00	0.38
≥2 days	1.00	0.90	1.00	0.63	1.00	0.42
≥3 days	1.00	0.91	1.00	0.67	1.00	0.46
≥12 days	0.91	0.96	0.94	0.81	0.96	0.61
≥52 days	0.50	0.99	0.59	0.93	0.72	0.81
≥270 days	0.05	1.00	0.04	1.00	0.04	0.99
AUC (SE)	0.98 (0.0007)		0.91 (0.0018)^‡		0.83 (0.0022)^{^‡^§}
Cannabis^†
≥1 day	1.00	0.94	1.00	0.79	1.00	0.69
≥2 days	1.00	0.95	1.00	0.81	1.00	0.71
≥3 days	1.00	0.96	1.00	0.82	1.00	0.73
≥12 days	0.90	0.97	0.96	0.87	0.98	0.80
≥52 days	0.59	0.99	0.72	0.92	0.80	0.86
≥270 days	0.13	1.00	0.18	0.98	0.33	0.96
AUC (SE)	0.98 (0.0005)		0.94 (0.0013)^‡		0.92 (0.0015)^{^‡^§}
Other Illicit Drugs^†
≥1 day	1.00	0.95	1.00	0.90	1.00	0.85
≥2 days	0.98	0.95	0.97	0.92	0.97	0.88
≥3 days	0.94	0.96	0.92	0.93	0.97	0.89
≥12 days	0.79	0.97	0.80	0.96	0.84	0.94
≥52 days	0.57	0.98	0.58	0.98	0.62	0.97
≥270 days	0.14	1.00	0.18	1.00	0.26	1.00
AUC (SE)	0.99 (0.0004)		0.97 (0.0008)^‡		0.97 (0.0009)^{^‡^§}

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 month.
↵† 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 to 17 and 18 to 20 year olds),
↵§ P < .0001.

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Appendix 8.

Performance of Substance Use Screens for Identifying Any Symptom of Alcohol, Cannabis, or Other Illicit Drug Use Disorder among Outpatient Subgroup (2013 to 2014)

	Age 12 to 15		Age 16 to 17		Age 18 to 20
	N = 14,699		N = 8353		N = 8453
	Se	Sp	Se	Sp	Se	Sp
Alcohol
≥1 day	1.00	0.88	1.00	0.63	1.00	0.47
≥2 days	1.00	0.92	1.00	0.69	1.00	0.51
≥3 days	1.00	0.93	1.00	0.74	1.00	0.55
≥12 days	0.84	0.97	0.87	0.88	0.95	0.72
≥52 days	0.38	0.99	0.45	0.96	0.63	0.88
≥270 days	0.02	1.00	0.03	1.00	0.03	1.00
AUC (SE)	0.98 (0.0006)		0.92 (0.0013)^*		0.86 (0.0017)^*^†
Cannabis
≥1 day	1.00	0.96	1.00	0.85	1.00	0.79
≥2 days	1.00	0.97	1.00	0.87	1.00	0.82
≥3 days	1.00	0.97	1.00	0.89	1.00	0.84
≥12 days	0.89	0.98	0.95	0.94	0.95	0.91
≥52 days	0.61	0.99	0.70	0.97	0.79	0.96
≥270 days	0.12	1.00	0.19	1.00	0.29	0.99
AUC (SE)	0.99 (0.0002)		0.98 (0.0006)^*		0.97 (0.0007)^*^†
Other Illicit Drugs
≥1 day	1.00	0.96	1.00	0.92	1.00	0.87
≥2 days	0.95	0.97	0.95	0.94	0.95	0.90
≥3 days	0.91	0.97	0.89	0.94	0.92	0.92
≥12 days	0.73	0.98	0.73	0.97	0.71	0.95
≥52 days	0.46	0.99	0.44	0.99	0.48	0.98
≥270 days	0.08	1.00	0.11	1.00	0.13	1.00
AUC (SE)	0.99(0.0004)		0.97 (0.0008)^*		0.97 (0.0009)^*^†

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.