Risk, reversibility and resilience of brain circuitries linked to opioid dependence: A diffusion tensor imaging study of actively opioid-using subjects and three comparison groups

Heroin use and neuropsychological impairments: comparison of intravenous and inhalational use

BACKGROUND AND OBJECTIVES

Injection and inhalational heroin use are associated with different levels of brain exposure to heroin and its metabolites and differences in the severity of dependence, which might lead to differential impacts on neuropsychological functions. We examined the difference and the magnitude of difference in the neuropsychological functions between inhalational and injection heroin-dependent subjects and also compared them with healthy controls.

METHODS

The study sample comprised three groups: 73 subjects with injection heroin dependence, 74 with inhalational heroin dependence, and 75 healthy controls (HC). We excluded patients with HIV, head injury, epilepsy, and severe mental illness. Neuropsychological assessments were done by Standard Progressive Matrices, Wisconsin Card Sorting Test (WCST), Iowa Gambling Task, Trail-Making Tests A and B (TMT), and Verbal and Visual Memory 1 and 2 Backtests (NBT). We estimated independent effects of the groups on various neuropsychological test parameters, adjusted for age and duration of dependence.

RESULTS

In the WCST, the inhalational heroin-dependent group took more trials to complete the first category and had higher scores in the failure to maintain set than controls. The intravenous group had higher total errors than controls in verbal working memory tests and Visual Working Memory 2 Backtest. This group scored higher commission errors in the Verbal 2 Backtest than the controls. The two groups of heroin users differed in failure to maintain set and Verbal Working Memory 2 Backtests. The effect sizes of the group differences were modest.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Either route of heroin use is associated with cognitive impairments; inhalational and injection use involve different cognitive domains.

Impulsivity across substance use categories: Consideration of sex/gender

PURPOSE OF REVIEW

The goal was to review recent (1/2015-2/2020) evidence of impulsivity as a feature of substance use disorders or use of substances (alcohol, cannabis, nicotine, opioids, stimulants) in males compared to females in terms of: a) impulsivity in substance-using groups (or substance-using compared to control groups), and b) relationship between impulsivity and substance use behavior, clinical severity, or treatment outcomes.

RECENT FINDINGS

Of 361 papers identified by the searches, 69 met inclusion criteria, and 39 were highlighted for considering sex/gender in relation to impulsivity in substance-using populations. Taken together, findings supported higher impulsivity in males and females who use substances, relative to controls; and higher impulsivity was linked with more substance use/severity in both sex/genders. There were mixed findings regarding male versus female differences in impulsivity among individuals who use substances, or in the magnitude of the relationship between impulsivity and substance use severity.

SUMMARY

The current body of evidence does not point to a consistent sex/gender difference in the role of impulsivity within and across substance use disorders. Impulsivity is a clinically-relevant construct for male and female individuals who use substances, across a range of substances.