Women tend to be more sensitive to the psychomotor-related behavioral and subjective effects of methamphetamine, a recent study found (Mayo et al., 2019). Could this help explain why women also tend to move from recreational use to dependence more quickly?
“We were interested in exploring individual differences in acute or early drug responses, before the development of a drug use disorder,” explained study author Leah Mayo, a postdoctoral researcher at Linköping University in Sweden.
“While many people will try drugs throughout their lives, only a minority (albeit a significant minority) will develop a substance use disorder. Doing studies like these in healthy, non-dependent humans allows us to understand how people vary in response to a medication and how that variation may make them more vulnerable or resistant to developing a drug use disorder.”
In the study, 44 men and 29 women completed four sessions in which they received either placebo or methamphetamine (20 mg) under double-blind conditions.
Approximately 30 minutes after each session, participants completed a monetary incentive delay in which they had to quickly respond to a target to win or avoid losing money. Participants also completed assessments of mood and medication effects. The researchers monitored their blood pressure and heart rate.
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“We found that women are more sensitive to the psychomotor effects of methamphetamine than men. In particular, women report feeling more “vigor” and less “fatigue” after taking the medication. Behaviorally, they also show faster reaction times in a reward processing task,” Mayo said.
The researchers suggest that this greater sensitivity to the behavioral and subjective effects of methamphetamine in women “may make them more likely to use the medication again, and perhaps increase their use over time.”
“We have shown that women are more sensitive to some of the effects of methamphetamine and hypothesize that this sensitivity may make them more vulnerable to developing problematic patterns of use. However, we still don’t know if this is true; That is, are those most sensitive to these pharmacological effects the most vulnerable to developing a use disorder? Mayo explained.
“We also don’t know how these effects change over time. More specifically, how do behavioral and subjective responses to methamphetamine change as drug use increases? “There are still many clinical questions to be answered, but we hope this study provides a starting point for understanding gender-based differences in the effects and use of methamphetamine.”
“An interesting observation is that the differences we report between men and women appear to be specific to methamphetamine. Work by others suggests that similar gender differences are not evident in response to the closely related drug D-amphetamine,” Mayo added.
“Surprisingly, very similar effects have been reported in preclinical animal models: the psychomotor effects of methamphetamine, but not D-amphetamine, differ between male and female rodents. The fact that this sex-based difference also exists in preclinical animal models opens the way to obtaining a more mechanistic understanding of the neurobiological foundations of these behaviors,” he concluded.
Bibliographic reference:
Mayo, L.M., Paul, E., DeArcangelis, J., Van Hedger, K., & de Wit, H. (2019). Gender differences in the behavioral and subjective effects of methamphetamine in healthy humans. Psychopharmacology, 236(8), 2413-2423. https://doi.org/
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