Excessive and harmful drinking is a key feature of an alcohol use disorder. The causes of substance use disorders are complex, but deficiences in certain aspects of self-control have been implicated. A tendency to react hastily and seek out risky situations has been linked to the process of addiction, and alterations in certain frontal regions of the brain have been associated both with impulsive and sensation-seeking behavior. In a study published in the journal Alcoholism: Clinical & Experimental Research, researchers have used brain imaging to further assess the links between self control and alcohol dependence.
The study, which took place in Germany, involved 62 patients who had been hospitalized with alcohol dependence and had recently detoxified, as well as 62 healthy people (non-dependent comparison group). Standard research questionnaires were used to assess participants' lifetime alcohol intake and to measure traits of impulsivity and sensation seeking. All participants had MRI scans, focusing on frontal brain regions associated with aspects of self control. From the scans, the amount of 'grey matter' ─ brain cells or neurons ─ in specific regions of interest could be determined.
The brain scans showed that, compared with the healthy participants, patients with alcohol dependence were deficient in grey matter in frontal areas of the brain that are known to be involved in self control. This is consistent with previous studies showing grey matter loss in long-term heavy drinkers. Patients also scored higher than the controls on measures of impulsivity, although there were no differences between the two groups in sensation seeking.
The researchers also looked for differences between two subgroups of alcohol-dependent patients: those with a very high lifetime alcohol intake, and those with a relatively lower intake. They found that the lower-intake patients scored more highly than high-intake patients on measures of sensation-seeking behavior, including 'thrill and adventure seeking'. They also showed that among the lower-intake subgroup, the volume of grey matter in one region of interest correlated with how highly patients scored for thrill and adventure seeking behavior (such that the greater the score, the larger the grey matter volume).
The researchers speculate that, in contrast to impulsivity, the trait of thrill and adventure seeking may play a protective role in lowering alcohol consumption and preserving prefrontal brain structure. This is consistent with previous findings that sensation seeking behavior may promote resilience to stress, which itself plays a major role in craving and addiction. More broadly the findings highlight that differences exist among individuals with a diagnosis of alcohol depdenence, and that individualized treatment strategies are needed.
Rosenthal, A., et al. (2019) Volumetric Prefrontal Cortex Alterations in Patients With Alcohol Dependence and the Involvement of Self‐Control. Alcoholism: Clinical and Experimental Research. doi.org/10.1111/acer.14211.