Previous studies have shown a difference exists between males and females with both use of cigarettes and quit attempts. It has been noted that males have both a more direct response to nicotine but also find the absence easier to cope with – inspiring more successful quit attempts. Women by contrast have demonstrated a far higher rate of relapse back to smoking and also respond more readily to visual cues such as seeing someone smoking or smelling cigarette smoke.
Researchers used positron emission tomography (PET) scans to see if there was a neurobiological reason for this behaviour. If the scans were able to illustrate different brain activity in response to nicotine the researchers would be able to make a link between cigarette/electronic cigarette use and the release of dopamine.
Dopamine is a chemical within the body that allows nerve cells to send messages to other nerve cells. It is linked to the way we process pleasurable activities and many addictive substances are associated with the body releasing increased levels of dopamine.
The use of PET scans is a method that has not been used extensively in the past for the study of smoking-related brain response due to the region of the brain involved and that the release of dopamine is too quick to observe. Researchers had to adapt the method of scanning so that they could measure the rapid hormone release.
Unlike the previous studies as covered here and here in the Planet of the Vapes news section, participants were allowed to smoke cigarettes during the scanning process. Rather than taking a set of single images the machine was altered to produce a series of quick scans in order to produce a “dopamine movie”.
The study successfully identified clear differences between the genders. Males demonstrated a large release of dopamine in a certain region of the brain that was not present in the studies of the females. The pattern was consistent with all men studied and absent in all women. A new series of scans were taken looking at the front section of the brain: again, males showed a rapid and marked peak in hormone release.
A third series of scans looking at the striatum section of the brain revealed the region where women experience the release of dopamine leading investigators to conclude that this is the region involved in female response to nicotine.
The team hope that this will prompt further studies into sex-specific behavioural responses and that the research can be carried out using larger numbers of participants.