Does DSM-5 nomenclature for inhalant use disorder improve upon DSM-IV?

The Effects of the Inhalant Toluene on Cognitive Function and Behavioral Flexibility: A Review of Recent Findings

Substance use disorder (SUD) is characterized, in part, by lack of control over drug seeking and taking. The prefrontal cortex (PFC) is highly involved in control of behavior and deficits in PFC structure and function have been demonstrated in clinical and preclinical studies of SUD. Of the various classes of drugs associated with the development of SUD, inhalants are among the least studied despite their widespread use among adolescents and children. In this work, we review what is currently known regarding the sites and mechanisms of action of inhalants with a focus on the volatile solvent toluene that is contained in a wide variety of legal and easily obtained products. We then describe how inhalants including toluene affect various behaviors with an emphasis on those associated with PFC function and how chronic use of inhalants alters brain structure and neuronal signaling. Findings from these studies highlight advances made in recent years that have expanded our understanding of the effects of inhalants on brain structure and reinforce the need for continued work in this field.

Commonalities and Differences Across Substance Use Disorders: Phenomenological and Epidemiological Aspects

BACKGROUND

Although psychoactive substances vary in many ways, they have important commonalties, particularly in their ability to lead to an addiction syndrome. The field lacks an updated review of the commonalities and differences in the phenomenology of alcohol, cannabis, tobacco, stimulants, opioids, hallucinogens, sedatives/tranquilizers, and inhalants and their related substance use disorders (SUDs).

METHODS

DSM-IV and DSM-5 SUD diagnostic criteria were reviewed, as was evidence from recent epidemiological and clinical research: psychometric studies (test-retest reliability, latent trait analysis); physiological indicators (tolerance, withdrawal); prevalence and age of onset. Information was incorporated from previous reviews, PubMed and Scopus literature searches, and data from large U.S. national surveys.

RESULTS

Empirical evidence in the form of test-retest reliability and unidimensionality supports use of the same DSM-IV dependence or DSM-5 SUD diagnostic criteria across substances. For most substances, the criteria sets were generally most informative in general population samples at moderate-to-severe levels of SUD. Across substances, 2 criteria (tolerance and use in hazardous situations) were identified as functioning differently in population subgroups. Since substances have different pharmacological effects, withdrawal is assessed using substance-specific symptoms, while tolerance is not; issues remain with the assessment of tolerance. Alcohol, tobacco, and cannabis were consistently identified as the substances with earliest onset of use, highest prevalence of lifetime use, and highest prevalence of lifetime disorder.

CONCLUSIONS

Despite differences between psychoactive substances, the generic DSM criteria set appears equally applicable across substances. Additional studies of tolerance and hazardous use will be useful for future nosologies. Alcohol, cannabis, and tobacco are the substances with the greatest public health impact due to the high prevalence and early onset of their use, and the potential all 3 substances have to lead to addiction.