Women's hormones play role in drug addiction and increases relapse rates: Study

While it is known that women's hormonal cycles may make them more prone to drug addiction, a recent study has suggested that it also makes them more prone to relapse.

Erin Calipari, an assistant professor of pharmacology at the Vanderbilt Center for Addiction Research, points out that women represent a particularly vulnerable population, with higher rates of addiction following exposure to drugs, but addiction studies have primarily focused on the mechanisms underlying these effects in men.

Her study found that, when fertility-related hormone levels are high, females learn faster, make stronger associations to cues in their environment and are more prone to seek rewards.

In this study, male and female rats were allowed to dose themselves with cocaine by pushing a lever, with a light set up to come on during dosing. That is similar to the environmental cues, such as drug paraphernalia, present when humans are taking drugs.

When their circulating hormone levels were high, female rats made stronger associations with the light and were more likely to keep pushing the lever as much as it took to get any amount of cocaine.

The findings were published in the Journal Neuropsychopharmacology.

Ultimately, females were willing to sacrifice more in the presence of these cues to get cocaine. The results are transferable to humans through behavioral economic analysis, which uses a complicated mathematical equation with values for the most and least a subject will do to get a payoff. It's one of the few ways that comparisons can be made across species.

"There is epidemiological data that says women are more vulnerable, but it's unclear what the factors are. We know they transition to addiction faster and have more problems with craving and relapse. Now, with research like this, we're beginning to isolate environmental and physiological causes," said Calipari.