Background & Aims: Despite the marketing of heroin in 1898 and its history as a public health concern, heroin use has not been a major topic of epidemiologic research (1). Little is known about the problems and experiences (PEs) during the earliest months following newly incident heroin use. These PEs after heroin use onset might arise and co-occur in pairwise or other multivariate association patterns that are consistent with the idea that there is a dimension of heroin use disorder (HUD). It might be assumed that this HUD dimension is comparable across subgroups, such as sex and history of other opioid use, but there is little evidence of this. Lastly, consequences of heroin use have not been fully explored in relation to an emerging public health concern about increased rates of stimulant related overdose concurrent with heroin related overdose. Thus, this dissertation aims: 1) To estimate the pairwise association between PEs of HUD. 2) To assess measurement equivalence of HUD, adopting a single dimension idea, across subgroups defined by sex and extra-medical prescription opioid use (EMPOU) history. 3) To investigate the degree to which onset of heroin use may precipitate excess risk of onset of stimulant use. Methods: The National Surveys on Drug Use and Health (NSDUH), 2002-2016, target population includes non-institutionalized United States (US) civilians age 12 years and older, including inhabitants of households, group quarters, and homeless shelters. Multi-stage area probability sampling identified 837,326 participants, 896 of whom were newly incident heroin users (NIHUs). Time intervals stratified NIHUs by elapsed time between first heroin use (i.e., within 12 months of assessment) and survey assessment. Pairwise combinations of PEs of HUD have been studied; odds ratios (ORs) have been estimated. The PEs were also combined into 10 diagnostic criteria indicators for an evaluation of measurement equivalence. Lastly, a case crossover design and analysis estimated the degree to which NIHU may lead to months of increased risk for starting extra-medical use of prescription stimulants or cocaine. Two-month hazard and control intervals were specified a priori. Results: The majority of PE to PE ORs suggested robust and statistically significant associations throughout time intervals from first use to up to 12 months after first use. Measurement equivalence evaluation indicated no difference between males and females, but suggested lack of measurement equivalence across EMPOU subgroups. Case crossover discordant pair odds ratios show no statistically significant increased risk of newly incident stimulant use within two months of NIHU. A post-estimation exploration of alternatives suggests use of one-month intervals. Discussion: The current study is novel as a US nation-scale community epidemiology study of the natural history of HUD. Other facets of novelty involve its fine-grain stratification of elapsed time since first heroin use, and its focus on individuals and aired PEs that develop over time. This dissertation also draws attention to the need for more precise HUD assessment considering EMPOU. There may be a linkage between NIHU and extra-medical stimulant use, but this topic deserves more attention in future research. Conclusions: First, heroin PEs now begin to coalesce into a HUD syndrome within 90-120 days after first heroin use. Second, female-male contrasts in level of HUD can now be made, but this is not the case for prescription opioid subgroups. Third, this study's evidence does not confirm a suspected triggering of stimulant use by heroin use.
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