Verbal memory, learning, and executive functioning among adolescent inhalant and cannabis users

Inhalant use is a common form of drug misuse among young adolescents. However, very little is known about how chronic inhalant misuse affects cognition. Several studies have examined cognitive deficits among inhalant users, but no study has thoroughly addressed the confounding issues frequently associated with inhalant users (e.g., polysubstance use). The aim of the current study was to examine possible deficits in memory, learning, and executive components of memory (interference susceptibility) among young, regular inhalant users relative to a statistically equivalent drug-using control group (primarily cannabis users) and a community control group.

Three groups of 21 young people (aged 13-24 years) were recruited: an inhalant- using group, a drug-using control group, and a community control group. The inhalant and drug-using controls were matched at the group level on demographic, clinical, and substance use measures. All three groups were statistically equivalent on age, sex, and education. The Rey Auditory Verbal Learning Test was used to assess memory, learning, and interference susceptibility.

Community controls performed significantly better than both drug-using groups, while inhalant users were more susceptible to proactive interference relative to drug-using controls.

Difficulty in successful proactive interference resolution demonstrated by the inhalant group may relate to inhalant-specific deficits in executive functioning. These findings raise important questions regarding the hypothesized toxicity of inhalants and of substance-specific cognitive deficits among regular adolescent substance users. Future studies should consider using more specific, experimental probes of cognitive functioning to identify potentially subtle changes among substance-using adolescents.