Researchers find that different brain areas linked to smoking and drinking

Research led by the University of Warwick has identified areas of the brain that are different in those who smoke and those who drink: the tendency to drink alcohol is associated with increased connectivity of brain networks associated with reward processing; and the tendency to smoke is associated with low connectivity of systems that respond to not receiving rewards. These differential tendencies to alcohol and nicotine consumption can even be detected in young people before much drinking or smoking has started.
In 2,000 participants they found that smokers had low functional connectivity in general, and especially in the lateral orbitofrontal cortex, a region of the brain associated with impulsive behaviour. This suggests that people who smoke may do so to increase their overall brain connectivity with the stimulating effect of nicotine; and that being impulsive may be a factor leading to smoking.
Drinkers of alcohol had high overall brain connectivity, especially in the medial orbitofrontal cortex, a region implicated in reward. It is suggested that the high connectivity of this reward-related brain region may be a factor in attracting some individuals to alcohol. Importantly the extent of these functional connectivity changes in the brains of drinkers and smokers correlated with the amount of alcohol and nicotine being consumed.
Critically they were even detectable in individuals smoking only a few cigarettes or drinking one unit of alcohol every day. Another key discovery is that it was possible to relate the connectivity at age 14 to who would smoke or drink at age 19. This opens up the issue of causality in addiction.
Professor Edmund Rolls, from the University of Warwick’s Department of Computer Science, commented “These discoveries help to show that there are different neural bases of different types of addiction, and that the orbitofrontal cortex, a key brain region in emotion, is implicated in these two types of addiction.”
Professor Jianfeng Feng, from the University of Warwick’s Department of Computer Science commented “These are key discoveries that advance our understanding of the neurological bases of smoking and drinking and also provide new evidence on the different neurological mechanisms that are related to these two types of human addictive behaviour… these advances have implications for prevention and treatment of these two substance use.”
Source: Decreased brain connectivity in smoking contrasts with increased connectivity in drinking. Wei Cheng, Edmund T Rolls, Trevor W Robbins, Weikang Gong, Zhaowen Liu, Wujun Lv, Jingnan Du, Hongkai
Wen, Liang eLife 2019;8:e40765.