Illicit drug use in English adolescent students–result of cumulative mediation analyses

Figures & data

Figure 1. Social Structure Social Learning Theory Framework.

Table 1. Variables of interest.

Variable	Question	Original Categories	Code	Recoded Categories	Code
Drug Use	Used any drugs last year. Derived Variable from the dataset	Used drugs Not used	1 2 –8 -9	Used drugs in the last year Not used Don’t Know Missing	0 1
Gender	Are you a boy or girl?	Boy Girl Don’t know Not answered	1 2 –8 -9	Boy Girl Missing	0 1 -8,-9
Age	How old are you now? Derived Variable from dataset	11 12 13 14 15 Don’t know Not answered	11 12 13 14 15 –8 -9	11 12 13 14 15 Missing	11 12 13 14 15 -8,-9
Region	Derived from dataset	North East North West East Midlands Yorkshire & Humber West Midlands East of England London South East South West	1 2 3 4 5 6 7 8 9	North East North West East Midlands Yorkshire & Humber West Midlands East of England London South East South West	1 2 3 4 5 6 7 8 9
Peer Differential Association	How many people your own age do you think take drugs?	All of them Most, but not all About half Some of them None of them Not applicable Don’t know Not answered	1 >0 2 > 0 3 > 1 4 > 1 5 > 2 –1 > 2 –8 -9	Most or all Half or less None Missing	0 1 2 –9/-8
Attitude Cannabis	Do you think it is OK for someone your age to do the following? Try taking cannabis	It’s OK It’s not OK Don’t know Not answered	1 2 3 –9	It’s OK It’s not OK Don’t know Missing	0 2 1 –9
Attitude cocaine	Do you think it is OK for someone your age to do the following? Try taking cocaine	It’s OK It’s not OK Don’t know Not answered	1 2 3 –9	It’s OK It’s not OK Don’t know Missing	0 2 1 –9
Attitude glue	Do you think it is OK for someone your age to do the following? Try sniffing glue?	It’s OK It’s not OK Don’t know Not answered	1 2 3 –9	It’s OK It’s not OK Don’t know Missing	0 2 1 –9
Parental Differential reinforcement	How do you think your family would feel if you started taking drugs? Filter question.	Try to stop me Persuade me not to Do nothing Encourage me Don’t know Not answered Not applicable	1 > 0 2 > 1 3 > 2 4>-9 5 > 2 –9>-9 -1 > 2	Strongly disapprove Disapprove Neither approve or disapprove Missing	0 1 2 –9
Imitation	Why did you try drugs for the first time? (Derived from dataset)	Because friends were doing it No Not answered Not applicable	1 > 1 0 > 0 –9>-9 -1 > 0	Because friends were doing it Other reasons Not answered	0 1 –9

Table 2. Descriptive Statistics.

Variable φc/(p-value)	Total cases & Missing cases	Category	Not Used Drugs Frequency/(%)	Used Drugs Frequency/ %
Gender*DrugsUsed (φc = .01 p = .26)	9137 (75.8%) 2914 (24.2%)	Boy (1) % Total %within Gender Girl (2) %Total %within Gender	3625 39.7% 83.2% 4017 44.0% 84.1%	733 8.0% 16.8% 762 8.3% 15.9%
Age 11–15*DrugsUsed (φc = .21 p < .001)	9176 (76.1%) 2875 (23.9%)	11 (1) %within Total %within Age 12 (2) %within Total %within Age 13 (3) %within Total %within Age 14 (4) %within Total %within Age 15 (5) %within Total %within Age	1261 13.7% 93.3% 1472 16.0% 91.0% 1801 19.6% 86.7% 1513 16.5% 80.7% 1623 17.7% 72.0%	91 1.0% 6.7% 145 1.6% 9.0% 276 3.0% 13.3% 362 3.9% 19.3% 632 6.9% 28.0%
Region*DrugsUsed (φc = .06 p < .001)	9302 (77.2%) 2749 (22.8%)	North East (1) %within total %within Region North West (2) %within Total %within Region York&Humber (3) %within Total %within Region East Midlands (4) %within Total %within Region West Midlands (5) %within Total %within Region East England (6) %within Total %within Region London (7) %within Total %within Region South East (8) %within Total %within Region South West (9) %within Total %within Region	1332 14.3% 84.4% 1031 11.1% 80.9% 1222 13.1% 85.2% 617 6.6% 83.7% 551 5.9% 84.1% 972 10.4% 83.7% 237 2.5% 77.2% 803 8.6% 81.6% 1008 10.8% 86.2%	247 2.7% 15.6% 244 2.6% 19.1% 212 2.3% 14.8% 120 1.3% 16.3% 104 1.1% 15.9% 189 2.0% 16.3% 70 0.8% 22.8% 181 1.9% 18.4% 162 1.7% 13.8%
Attitude Cannabis*DrugsUsed (φc = .45 p < .001)	9121 (75.7%) 2930 (24.3%)	It’s Ok to try (1) %within Total %within Att. Can It’s not OK (2) %within Total %within Att. Can Don’t Know (3) %within Total %within Att. Can	391 4.3% 38.7% 6699 73.4% 90.8% 555 6.1% 75.7%	620 6.8% 61.3% 678 7.4% 9.2% 178 2.0% 24.3%
Attitude Cocaine*DrugsUsed (φc = .22 p < .001)	9087 (75.4%) 2964 (24.6%)	It’s Ok to try (1) %within Total %within Att. Coc It’s not OK (2) %within Total %within Att. Coc Don’t Know (3) %within Total %within Att. Coc	100 1.1% 39.4% 7087 78.0% 85.8% 426 4.7% 74.6%	154 1.7% 60.6% 1175 12.9% 14.2% 145 1.6% 35.4%
Attitude Glue*DrugsUsed (φc = .26 p < .001)	9149 (75.9%) 2902 (24.1%)	It’s Ok to try (1) %within Total %within Att. Glue It’s not OK (2) %within Total %within Att. Glue Don’t Know (3) %within Total %within Att.Glue	392 4.3% 53.6% 6262 68.4% 87.9% 1011 11.1% 78.4%	340 3.7% 46.4% 866 9.5% 12.1% 278 3.0% 21.6%
Imitation *DrugsUsed (φc = .25 p < .001)	9044 (75.0%) 3007 (25.0%)	Friends were taking (1) %within Total %within Imitation Other reason (2) %within Total %within Imitation	30 0.3% 18.5% 7628 84.3% 85.9%	132 1.5% 81.5% 1254 13.9% 14.1%
Peer Association *DrugsUsed (φc = .29 p < .001)	4699 (39.0%) 7352 (61.0%)	Most or all (1) %within Total %within peer assoc. Half or less (2) %within Total %within peer assoc. None(3) %within Total %within peer assoc.	101 2.1% 45.5% 2418 51.5% 80.7% 1410 30.0% 95.3%	121 2.6% 54.5% 580 12.3% 19.3% 69 1.5% 4.7%
Parental Reinforcement *DrugsUsed (φc = .21 p < .00)	8871 (73.6%) 3180 (26.4%)	Strongly disapprove (1) %within Total %within Parental Reinf. Disapprove (2) %within Total %within Parental Reinf. Neither (3) %within Total %within Parental Reinf.	2928 33.0% 93.4% 321 3.6% 89.9% 4136 46.6% 76.9%	208 2.3% 6.6% 36 0.4% 10.1% 1242 14.0% 23.1%
Total (N)	12,051

Figure 2. (SL Model 1).

Figure 3. (SS Model 1).

Figure 4. (SSSL Model 3).

Table 3. Social Structure Model.

	Social Structure Model
	Exp(B)/Odds Ratio	Significance (p value)	B	S.E
11 years	.19	.00	−1.69	.12
12 years	.25	.00	−1.38	.10
13 years	.38	.00	−.978	.08
14 years	.61	.00	−.50	.08
15 years	-	-	-	-
Female	1.06	.35	.06	.06
Male	-	-	-	-
North East (1)	1.18	.16	.16	.11
North West (2)	1.44	.00	.37	.12
York & Humber (3)	1.12	.32	.12	.12
East Midlands (4)	1.30	.06	.26	.14
West Midlands (5)	1.06	.70	.06	.14
East England (6)	1.30	.03	.26	.12
London (7)	2.03	.00	.71	.17
South East (8)	1.45	.00	.37	.12
South West (9)	-	-	-	-
Model Fit
Chi-square	438.28 (df. 13)	.00
Nagelkerke Pseudo R^2	.08

^*(values rounded off to 2 dp)

Table 4. Social Learning Model.

	Social Learning Model
	Exp(B)/ Odds Ratio	Significance (p value)	B	S.E
Attitude Cannabis- OK	9.78	.00	2.28	.17
Attitude Cannabis- Not sure	4.22	.00	1.44	.23
Attitude Cocaine-OK	1.08	.81	.08	.33
Attitude Cocaine- Not sure	.47	.01	−.76	.29
Attitude Glue- OK	2.13	.00	.76	.19
Attitude Glue Not sure	.81	.28	−.21	.20
Fam Reinf. Strongly disapprove	.06	.00	−2.75	.14
Fam Reinf disapprove	.07	.00	−2.74	.27
Peer Assoc. Most or all	14.40	.00	2.67	.30
Peer Assoc. Some or less than half	3.47	.00	1.24	.20
Imitation- Yes	8.46	.00	2.14	.28
Model Fit
Chi-square	1626.61 df (11)	p ≤ .001
Nagelkerke Pseudo R^2	.59

^*(values rounded off to 2 dp)

Table 5. Cumulative Social Structure Social Learning Model.

	Model1 SS–>DU		Model 2 SL–>DU		Model 3 SS–>SL–>DU
Drugs used Last Year	Exp(B)	Sig	Exp(B)	Sig	Exp(B)	Sig	B	SE
11 years	.19	.00			.50	.02	−.70	.30
12 years	.25	.00			.66	.08	−.42	.24
13 years	.38	.00			.99	.96	−.01	.20
14 years	.61	.00			.83	.29	−.19	.18
15 years	-	-			-	-	-	-
Male	1.06	.35			1.13	.39	.12	.14
Female	-	-			-	-	-	-
North East (1)	1.18	.16			1.22	.43	.20	.25
North West (2)	1.44	.00			.94	.83	−.06	.26
York&Humber (3)	1.12	.32			.97	.91	−.03	.26
East Midlands (4)	1.30	.06			.86	.64	−.15	.33
West Midlands (5)	1.06	.70			1.38	.29	.33	.31
East England (6)	1.30	.03			.72	.24	−.33	.28
London (7)	2.03	.00			1.93	.07	.66	.36
South East (8)	1.45	.00			1.00	.99	−.00	.28
South West (9)	-	-			-	-	-	-
Attitude Cannabis- OK			9.78	.00	8.57	.00	2.15	.19
Attitude Cannabis- Don’t know			4.22	.00	3.92	.00	1.37	.24
Attitude Cocaine-OK			1.08	.81	1.18	.64	.17	.35
Attitude Cocaine- Don’t know			.47	.01	.46	.01	−.77	.30
Attitude Glue- OK			2.13	.00	2.00	.00	.71	.20
Attitude Glue Don’t know			.81	.28	.85	.40	−.17	.20
Fam Reinf. Strongly disapprove			.06	.00	.06	.00	−2.78	.14
Fam Reinf. Strongly disapprove			.07	.00	.07	.00	−2.73	.27
Peer Assoc. All or most			14.40	.00	12.04	.00	2.49	.31
Peer Assoc. Half or some			3.47	.00	3.00	.00	1.10	.27
Imitation			8.46	.00	8.40	.00	2.13	.28
Model Fit
Chi-square	1610.64 df(24)	p ≤ .001
Nagelkerke Pseudo R^2	.600

^*(values rounded off to 2 dp)