Inhalant use and formal DSM-IV inhalant use disorders (IUDs) remain a curious case study in the annals of psychiatric epidemiology. For more than thirty years, nationally representative surveys have identified inhalant use as among the most prevalent forms of adolescent substance use [1, 2]. For example, findings from the 2006 Monitoring the Future survey indicated that 16.1% of U.S. 8th graders had used inhalants, compared to 15.7% who had used marijuana/hashish, and 7.3%, 3.4%, 3.4%, and 1.4% who had used amphetamines, hallucinogens, cocaine, and heroin, respectively . Wu and colleagues recently estimated that two million 12-to-17 year-olds in the U.S. had used inhalants based on data from the National Survey on Drug Use and Health .
A small corpus of animal studies, case reports, and clinical investigations further suggests that malignant health and social outcomes may attend adolescent inhalant use. Inhalant use has been implicated in documented cases of cardiac, renal, and liver toxicity and hepatorenal failure [5–7], bowel and bladder dysfunction , bone marrow suppression and reduced T-cell responsivity [9, 10], irreversible congestive heart failure , severe neurological damage and cognitive dysfunction [12, 13], effects in offspring similar to those of fetal alcohol syndrome , and a host of psychiatric, social, academic, and interpersonal functional impairments [15–19].
Despite these troubling findings, inhalant use remains poorly understood and the least studied of the psychoactive substances of abuse. In his presidential address to the College on Problems of Drug Dependence, Balster referred to inhalant use as "the hidden epidemic," noting the curious disjunction between the seriousness of the problem and the insubstantial scientific and clinical responses to it . IUDs have been included in the Diagnostic and Statistical Manual of Mental Disorders (DSM) since 1980, although the brief discussion of these disorders in DSM-IV is testament more to the sheer absence of available findings vis-à-vis prevalence, course, subtypes, comorbid mental health and medical conditions, and specific clinical and sociodemographic features than a useful guide to the diagnosis of these disorders . Additional research on IUDs is needed to support a more refined, substantive, and clinically useful discussion of IUDs in DSM-V.
One particularly important unresolved issue concerns the validity of the DSM-IV distinction between inhalant abuse and inhalant dependence disorders. Although the generic DSM-IV substance dependence disorder criteria set applied to most substance use disorders includes a criterion reflecting presence versus absence of a characteristic withdrawal syndrome, this criterion is not included in the inhalant dependence disorder criteria set. Further, as recognized in DSM-IV , other generic substance use disorder criteria may have been included in the IUD criteria sets inappropriately. For example, one generic substance dependence criterion assesses whether "a great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects." However, it is unlikely that inhalant users spend a great deal of time accessing inhalants, given their ubiquity in the physical environment. We are not aware of any prior studies of the latent structure of DSM-IV IUDs. Findings of this nature could shed light on current proposals to move from a categorical (abuse vs. dependence) to unidimensional conceptualization of substance use disorder (i.e., dependence) in DSM-V [22–25]. Further research on IUDs in general is needed to improve screening, treatment and prevention.
The current study attempts to address these gaps in knowledge by focusing on a large sample of delinquent youth. Delinquent youth have among the highest rates of inhalant use identified in prior studies of community, clinical, and criminological samples. These findings suggest that delinquent youth may also be at comparatively high risk for IUDs. For example, Howard and Jenson identified lifetime inhalant use in 34.3% of 475 adolescents on probation in Utah . Similar results were reported by Howard, Balster, Cottler, Wu, and Vaughn , who found that nearly 40 percent of 723 antisocial youth residing in Missouri State Division of Youth Services' residential rehabilitation facilities had used inhalants for the expressed purpose of becoming intoxicated. Howard et al.  examined characteristics of inhalant use in a state population of delinquent youth, including prevalence and patterns of use and differences between inhalant users and nonusers. Findings indicated that race/ethnicity, geographic area of residence, fearlessness, sucidality, and polydrug use distinguished inhalant users and nonusers in multiple logistic regression analyses.
Using the same data source as Howard et al. , Perron and Howard  examined correlates of IUDs. They found that delinquents with IUDs (particularly dependence) reported more extensive histories of antisocial behavior, trauma, substance-related problems, suicidal ideation, and higher current levels of anxious/depressive symptoms than did inhalant nonusers or users without IUDs. Youth with IUDs had significantly more substance-related problems and greater suicidal ideation than inhalant nonusers.
The current study extends Howard et al.'s  and Perron and Howard's  investigations by examining the prevalence and diagnostic performance of DSM-IV inhalant abuse and dependence disorders and their constituent criteria. These issues were not examined in the prior reports [27, 28] but are important. More specifically, studies of community and clinical samples reveal that high rates of lifetime inhalant use do not necessarily imply high rates of DSM-IV IUDs [29, 30]. However, statewide surveys [26, 27] indicate that delinquent youth, particularly those in the juvenile justice system, may be at high risk for IUDs. Our review of the scientific literature pertaining to inhalants did not locate other prior investigations of DSM-IV IUDs in juvenile justice service populations. Thus, this investigation examined 1) the prevalence of DSM-IV inhalant abuse and inhalant dependence and constituent criteria in a state population of delinquent youth at substantial risk for these disorders, and 2) the latent structure of DSM-IV IUDs and concordance between DSM-IV IUDs and empirically-derived classes of adolescent inhalant users identified via latent class analysis of DSM-IV IUD diagnostic criteria. Results of this study may provide a foundation for improved screening, treatment, and prevention of IUDs in juvenile justice settings.