Does DSM-5 Nomenclature for Inhalant Use Disorder Improve Upon DSM-IV?

Nomenclature for substance use disorder (SUD) consequent to using inhalants (SUD-I) remains obscure for multiple reasons including lacking nosology evidence, parsing inhalants between DSM drug classes, controversy over key diagnostic features, and scant utilization in applied settings. Central goals of DSM-5 revisions were to “…provide the best available description of how [the] disorders are expressed…,” “aid in the accurate diagnosis and treatment…,” and “alleviate … misunderstandings” (APA, 2013, p. xli and p. xlii, respectively). This study evaluated how well these goals were accomplished specifically for SUD-I. DSM-5 and DSM-IV nomenclatures for SUD-I were patterned after diagnostic criteria designed for other drug classes. However, inhalants are distinct among addictive substances in multiple ways. As a drug class, ‘inhalants’ encompasses thousands of compounds. Most inhalants are legal to possess at any age, inexpensive, easily obtained, and their intense intoxication typically lasts only a few minutes per dose. Their ubiquity for their manufactured uses helps conceal inhalant misuse (Dinwiddie, 1994). All of these features likely contribute to the onset and inhalant use (IU) at younger ages relative to other substances. Although IU poses manifold serious health risks (e.g., asphyxiation, ataxias, cardiac arrest, cerebral atrophy, chemical burns, reduced immune function, kidney failure, neuropathy), conventional wisdom considers IU to not be dangerous. Consequently, parents, teachers and even health professionals are generally not knowledgeable about or vigilant for signs of IU (Sikes, Walley, McBride, Fusco, Cole & Lauka, 2011). For example, development of prevention and treatment programs for SUD-I has lagged compared to other SUDs and has largely occurred outside the U.S. (Gruenewald, Johnson, Shamblen, Ogilvie, & Collins, 2009; Ridenour & Howard, 2012). Neglect of SUD-I also is evident in rudimentary research. Prevalence of DSM-III-R SUD-I dependence was reported as 0.3% in the early 1990s (Anthony, Warner, & Kessler, 1994) and DSM-IV dependence as < 0.1% and abuse as 0.3% in the early 2000s (Compton, Conway, Stinson, Colliver & Grant, 2005). However, these nomenclatures categorized aerosols, solvents and most gases as SUD-I in aggregate whereas nitrous oxide and nitrites were categorized as “other” substances. Thus, SUD-I prevalence in aggregate and for specific inhalant types remains largely unknown. Moreover, little psychometric evidence is available for SUD-I assessment. DSM-IV versus DSM-5 A prerequisite to researching SUD-I epidemiology, etiology, treatment and prevention is establishing a diagnostic nomenclature, which was the focus of the present study. Extant nosology research on SUD-I is largely grounded in DSM-IV nomenclature, as most SUD-I studies have occurred during the last decade. Considerable revisions to SUD-I occurred in DSM-5. For example, DSM-IV dependence and abuse diagnoses were combined into a single disorder that is graded in terms of severity. Item response theory studies of DSM-IV SUD criteria using mostly clinical samples support this revision across many drug classes and for adolescents (e.g., Gelhorn et al. 2008; Hartman et al., 2008; Hasin, Fenton, Beseler, Park, & Wall, 2012; Martin, Chung, Kirisci, & Langenbucher, 2006; Saha et al., 2012). Studies of SUD-I also support this revision (Ridenour, Bray & Cottler, 2007); extant IRT studies of SUD-I criteria were of juveniles involved with the criminal justice system (Perron et al., 2010) or general population adults (Kerridge et al., 2011). DSM-5 revisions also eliminated the DSM-IV criterion of substance use causing legal problems and added a “craving” criterion (APA, 2013). Recent studies demonstrated that legal problems correlate highly with SUD-I (Kerridge et al., 2011; Perron et al., 2010); however, this finding has not always been replicated (Ridenour et al., 2007) and in samples recruited outside of the justice system, the prevalence of the legal problems criterion is 2.0% or less (Kerridge et al., 2011; Ridenour et al., 2007). Thus, the utility of legal problems as a diagnostic criterion for SUD-I remains unclear. The craving criterion is included in International Classification of Diseases (10th Edition; WHO, 1990); however, to our knowledge, no nosology evidence exists pertaining to a craving criterion for SUD-I. An additional debate focusses on whether SUD-I withdrawal exists (which DSM-IV and -5 both exclude). Symptoms which typify withdrawal from substances other than inhalants highly discriminated general-population adults with DSM-IV SUD-I dependence from adults with abuse or only IU (Perron et al., 2011). However, no cluster of a distinct set of withdrawal symptoms has been found to comprise a syndrome per se (Perron et al., 2011; Ridenour et al., 2007). A final deliberation involves parsing of putative types of inhalants into different drug classes. DSM-IV and -5 exclude from SUD-I the nitrite inhalants (amyl, butyl, and isobutyl nitrites) and nitrous oxide (a gas), which are assigned to the “other (or unknown)” class. The “other” class consists of drugs for which “the extent and range of induced disorders are uncertain” (p. 584; APA, 2013). Present Study Toward finalizing SUD-I nomenclature, study aims were to quantify differences between DSM-IV and DSM-5 nomenclatures; test the hypothesis that (a) different putative types of inhalants and (b) SUD-I criteria of DSM-IV and DSM-5 manifest a single construct; and contribute to the literature evidence from a community-recruited sample of older adolescents and young adults, the age range of greatest SUD incidence (Chen, O’Brien, & Anthony, 2005; Grant, Dawson, Stinson, Chou, Dufour & Pickering, 2004). Moreover, it was hypothesized that kappa of .6 (good reliability) or greater occurs between ‘gold standard’ structured and unstructured clinical interviews of SUD-I. Finally, DSM-IV and DSM-5 nomenclatures were compared in terms of the number persons each renders who meet at least one criterion, but not a diagnosis (so-called diagnostic orphans) (Degenhardt, Coffey, Carlin, Swift, & Patton, 2008; Harford, Yi, & Grant, 2010).