Understanding marijuana use initiation vs. frequency of use on risk for hallucinogen use: testing for mediating mechanisms underlying the gateway hypothesis

Figures & data

Figure 1. Mediation Model linking marijuana use to hallucinogen Use.

Table 1. Descriptive statistics.

	Mean/Proportion	Standard Deviation	Minimum	Maximum
Hallucinogen Use Wave 3 No = 97.61% (N = 897) Yes = 2.39% (N = 22)
Ever Used Marijuana Prior to Baseline No = 20.35% (N = 200) Yes = 79.65% (N = 783)
Most Ever Used Marijuana Prior to Baseline	5.661	3.356	1	9
Impulse Control at Wave 2	3.192	.922	1	5
Sensation-Seeking at Wave 2	13.029	3.379	4	20
Depression at Wave 2	.432	.620	0	3.67
Deviant Peer Association at Wave 2	.883	.861	0	4
Gender Male = 86.88% (N = 854) Female = 13.12% (N = 129)
Race Black = 49.24% (N = 484) Hispanic = 33.57% (N = 330) White = 13.02% (N = 128) Other Race = 4.17% (N = 41)
Socioeconomic Status at Baseline	51.967	12.470	11	77
Exposure to Violence at Wave 2 No = 45.47% (N = 417) Yes = 54.53% (N = 500)
Number of Waves with Valid Data	8.977	1.998	0	10
Age at Wave 3	16.966	1.155	15	19
Days in Wave 3 Observation Period	175.747	30.533	61	245
Proportion of Wave 3 Spent in Secure Facilities	.423	.437	0	1

Table 2. Generalized structural equation modeling logistic regression of ever having use marijuana prior to baseline on hallucinogen risk at wave 3 (N = 917).

	Model 1			Model 2
	Coefficient	p-Value	95% Confidence Interval	Coefficient	p-Value	95% Confidence Interval
Ever Used Marijuana Prior to Baseline (0=No; 1=Yes)	1.085	.159	−.425 2.594	.629	.445	−.987 2.246
Impulse Control (Wave 2)	—	—	—	−.381	.329	−1.146 .383
Sensation-Seeking (Wave 2)	—	—	—	.054	.603	−.150.258
Depression (Wave 2)	—	—	—	.376	.375	−.455 1.207
Deviant Peer Association (Wave 2)	—	—	—	.463	.180	−.213 1.138
Gender (0=Male; 1=Female)	.126	.848	−1.162 1.415	−1.085	.348	−3.350 1.180
Race (reference=White) Black Hispanic Other Race	−1.473 −1.342 −13.692	.010 .035 .981	−2.592–.354 −2.590–.093 −1166.293 1138.908	−1.168 −1.358 −12.524	.109 .093 .973	−2.958 .262 −2.940.225 −727.533 702.486
Socioeconomic Status at Baseline	.006	.766	−.035 .048	−.003	.910	−.049 .044
Exposure to Violence (0=No; 1=Yes) (Wave 2)	.358	.454	−.579 1.295	−.513	.419	−1.759 .733
Age	−.171	.406	−.574 .232	−.288	.264	−.794 .217
Days in Observation Period	>-.001	.992	−.015 .015	.004	.697	−.014 .022
Proportion of Observation Period Spent in Secure Facilities	.045	.935	−1.026 1.116	−.724	.320	−2.150.702
Number of Waves with Valid Data	.001	.996	−.324 .326	.038	.880	−.452 .527
Constant	−1.349	.758	−9.939 7.240	2.155	.727	−9.935 14.246
Marijuana Use→Impulse Control	—	—	—	−.186	.013	−.332–.040
Marijuana Use→Sensation-Seeking	—	—	—	1.371	<.001	.798 1.944
Marijuana Use→Depression				.092	.098	−.017 .201
Marijuana Use→Deviant Peer Association	—	—	—	.389	<.001	.253 .525

Table 3. Generalized structural equation modeling logistic regression of marijuana use frequency prior to baseline on hallucinogen risk at wave 3 (N = 917).

	Model 1			Model 2
	Coefficient	p-Value	95% Confidence Interval	Coefficient	p-Value	95% Confidence Interval
Highest Frequency Ever Used Marijuana Prior to Baseline	.178	.031	.016 .341	.090	.362	−.103 .282
Impulse Control (Wave 2)	—	—	—	−.348	.360	−1.124 .409
Sensation-Seeking (Wave 2)	—	—	—	.053	.612	−.152 .258
Depression (Wave 2)	—	—	—	.382	.364	−.442 1.206
Deviant Peer Association (Wave 2)	—	—	—	.407	.256	−.296 1.111
Gender (0=Male; 1=Female)	−.027	.968	−1.343 1.289	−1.156	.322	−3.445 1.132
Race (reference=White) Black Hispanic Other Race	−1.580 −1.471 −15.029	.006 .025 .990	−2.717–.442 −2.754–.188 −2337.652 2307.594	−1.220 −1.390 −12.594	.096 .089 .972	−2.655 .215 −2.993 .212 −721.553 626.366
Socioeconomic Status at Baseline	.006	.774	−.035 .048	−.004	.872	−.050.043
Exposure to Violence (0=No; 1=Yes) (Wave 2)	.322	.505	−.624 1.267	−.483	.448	−1.732 .766
Age	−.218	.301	−.631 .195	−.309	.236	−.819 .202
Days in Observation Period	.001	.947	−.015 .016	.004	.698	−.015 .022
Proportion of Observation Period Spent in Secure Facilities	−.051	.927	−1.150 1.047	−.776	.294	−2.226 .674
Number of Waves with Valid Data	.015	.928	−.312 .343	.049	.843	−.440.538
Constant	−.660	.882	−9.369 8.049	2.555	.679	−9.536 14.645
Marijuana Use→Impulse Control	—	—-	—	−.035	<.001	−.052–.017
Marijuana Use→Sensation-Seeking	—	—	—	.180	<.001	.111 .248
Marijuana Use→Depression	—	—	—	.009	.162	−.004 .022
Marijuana Use→Deviant Peer Association	—	—	—	.070	<.001	.054 .086