Newswise — Rockville, Md. (October 19, 2021)—The results of several new studies focusing on sex differences in pain and addiction indicate females could be more susceptible to drug addiction and addiction-like behaviors than males. Researchers also explored the role of lack of sleep on the likeliness to relapse. This is due in part to hormone differences in females and males. Data from the studies will be presented virtually October 19–22 at the American Physiological Society’s seventh conference on New Trends in Sex and Gender Medicine.

Sleep Disruption May Increase Risk of Opioid Addiction Relapse

This study was conducted in a rat model to examine the connection between opioid abstinence and persistent sleep loss and its impact on the body’s central stress response system. Researchers specifically focused on adult female and male rats and found persistent sleep disruption may cause or perpetuate abnormalities in their response system, which is also known as the hypothalamic-pituitary adrenal axis. These abnormalities increase the risk of vulnerability to relapse during oxycodone abstinence in some individuals. Scientists are now working to identify susceptibility factors that play a role in boosting the risk of relapse. The takeaway, according to researchers, is that adequate sleep may be critical for a successful recovery from opioid addiction.

Heroin and Fentanyl Use Rising Nationally During COVID-19 Following Changes to Opioid Prescribing

Researchers conducting this study explored how the opioid epidemic in the U.S. continues and evolved during the ongoing COVID-19 pandemic. The data show that women have been and continue to make up the majority of those prescribed opioids for pain treatment. The findings also show that use of prescribed opioids for pain management became the primary conduit to abuse and addiction for women. The critical finding: Mitigation efforts in opioid prescribing have been followed by increases in the use of other substances, such as heroin and fentanyl, in both men and women. Although the rate of opioid use and overdose is higher in men, women have a higher rate of overdose death. Understanding how opioid use and addiction affect men and women differently is central to ending the epidemic.

Females Are More Vulnerable to Addiction than Males

Scientists used a rat model to conduct this study to evaluate sex differences in vulnerability to addiction. Their results indicate activation of a specific subset of receptors for estrogens enhances established cocaine-seeking behaviors in female rats. In male rats, the preference for cocaine under the same circumstances was reduced. Researchers found these results in the area of the brain linked to compulsive behaviors. Females show a greater response than males to stimulants such as amphetamine and cocaine in part due to the gonadal hormone estradiol, which is one of the three forms of estrogen. The hope is these results will lead to a better understanding of the mechanisms of addiction-related behaviors and the development of sex-specific treatments for addiction.

NOTE TO JOURNALISTS: To schedule an interview with conference organizers, a member of the research team, and/or request a specific abstract, please contact APS Media Relations or call 301.634.7314. Find more research highlights in the APS Newsroom.

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Journal Link: New Trends in Sex and Gender Medicine