A study at University of Montreal, Canada, suggests that the menstrual cycle appears to have an effect on nicotine cravings.
According with Adrianna Mendrek, affiliated with the Department of Psychiatry at the University of Montreal and the Research Centre at the Mental Health University Institute of Montreal (IUSMM) and principal author of the study, incontrollable urges to smoke are stronger at the beginning of the follicular phase that begins after menstruation. Study data reveled that hormonal decreases of estrogen and progesterone possibly deepen the withdrawal syndrome and increase activity of neural circuits associated with craving.
Therefore, smoker women would overcome easier abstinence-related withdrawal symptoms during the mid-luteal phrase, i.e. after ovulation, when their levels of estrogen and progesterone are elevated. Taking the menstrual cycle into consideration could help women to stop smoking,” Mendrek said.
The research included 34 individuals (19 women and 15 men) who each smoke more than 15 cigarettes a day. They filled out questionnaires and underwent MRI brain scans, which were taken while they looked at either neutral pictures or pictures designed to make them want to smoke. The women were scanned twice – once at the beginning of the follicular phase of their menstrual cycle and then again at the mid-luteal phase. Estrogen and progesterone levels were also measured.
The researchers led their study with two specific objectives in mind. The first was to check if there are gender differences in the neronal circuits linked to craving. The second was to determine if the electrocortical changes associated with nicotine withdrawal fluctuate in relation to hormone variations.
No significant differences were found between the men and women in terms of neuronal circuits linked with the reward-pleasure system. However, the activation patterns for the females varied considerably over their menstrual cycle. Certain areas of their frontal, temporal and parietal cortex revealed greater activation during the follicular phase, while limited activation was recorded in the hippocamp during the luteal phase. For the first time, this study showed this distinction in the female brain activation.
After a year, less than one ex-smoker in ten manages to stay that way. Women who smoke have a harder time quitting than men, even when they smoke the same amount. In studies involving rodents that were exposed to nicotine and other substances, scientists have observed sex differences. “Female rats become addicted more quickly, and are willing to work harder for the same quantity of dose,” Mendrek explained. This observation led the research team to conclude that females are perhaps at higher risk of addiction, and sex hormones could be the reason why.
However, the situation is much more difficult to unravel when it comes to humans. “Stress, anxiety and depression are probably the more important factors to take into consideration,” Mendrek said. Each smoker is unique in terms of his or her tobacco use, personal history, personality, social situation and environment.
According with Mendrek, tobacco use by young women is unfortunately increasing. She hopes her conclusions will encourage researchers to pay greater attention to biology when designing their research protocols. “A greater knowledge of the neurobiological mechanisms governing addiction should enable us to better target treatment according to the smokers profile,” she said.
The findings were published in Psychiatry Journal.
Through: University of Montreal UdeMNouvelles
