Progression to regular heroin use: examination of patterns, predictors, and consequences

Abstract

Background: The present study retrospectively evaluated the chronology and predictors of substance use progression in current heroin-using individuals.

Methods: Out-of-treatment heroin users (urinalysis-verified; N=562) were screened for laboratory-based research studies using questionnaires and urinalysis. Comprehensive substance use histories were collected. Between- and within-substance use progression was analyzed using stepwise linear regression models.

Results: The strongest predictor of onset of regular heroin use was age at initial heroin use, accounting for 71.8% of variance. The strongest between-substance predictors of regular heroin use were ages at regular alcohol and tobacco use, accounting for 8.1% of variance. Earlier onset of regular heroin use (≤20 years) vs. older onset (≥30 years) was associated with a more rapid progression from initial to regular use, longer duration of heroin use, more lifetime use-related negative consequences, and greater likelihood of injecting heroin. The majority of participants (79.7%) reported substance use progression consistent with the gateway hypothesis. Gateway-inconsistent individuals were more likely to be African-American and to report younger age at initial use, longer duration of heroin use, and more frequent past-month heroin use.

Conclusions: Our findings demonstrate the predictive validity and clinical relevance of evaluating substance use chronology and the gateway hypothesis pattern of progression.

Keywords: Gateway hypothesis; Heroin use disorder; Opioid; Substance use progression.

Fig. 1

Initial substance consumption is characterized (% of sample; N = 562) by substance(s) used first across participants.

Fig. 2

Age at onset of regular heroin use (≥3 uses per week) is depicted as a function of age at onset of regular alcohol use (≥3 uses per week). Percentage of each tertile of age at onset of regular alcohol use (earlier [8–16 years], intermediate [17–19 years], and later [20+ years]) is plotted on the y-axis and considered chronologically by age (years) at onset of regular heroin use (x-axis).

Fig. 3

Age at onset of regular heroin use (≥3 uses per week) is depicted as a function of age at onset of regular tobacco use (≥3 uses per week). Percentage of each tertile of age at onset of regular tobacco use (earlier [8–15 years], intermediate [16–18 years], and later [19+ years]) is plotted on the y-axis and considered chronologically by age (years) at onset of regular heroin use (x-axis).

Fig. 4

Substance use progression among gateway-consistent individuals (n = 401) is plotted by age at onset. Each substance displayed in its own node (box) indicates that substance was used in temporal isolation (participant reported only the one substance initiated in that calendar year). Mean age at onset for each substance or combination of substances is depicted M (±1 SD). Percentages displayed are the proportion of gateway-consistent individuals. More common pathways and nodes are bolded for emphasis. To reduce complexity, less populated nodes and minor pathways of drug progression (n ≤ 25) were omitted, and thus pathways and nodes will not sum to 100% of the sample.