People With Type 2 Alcoholism Experience Unique Brain Changes

Type 2 alcoholism is a term sometimes used to refer to a subset of people with alcoholism who tend to display antisocial behavior. In a study published in October 2014 in the journal Alcohol and Alcoholism, a team of Finnish and Swedish researchers compared the brains of type 2 alcoholics to the brains of type 1 alcoholics and people unaffected by alcoholism. These researchers concluded that individuals with type 2 alcoholism may undergo unique brain changes associated with the processing of a key chemical called serotonin.

Type 1 and Type 2 Alcoholism

Type 1 and type 2 alcoholism are not official designations. Instead, they are categories that help addiction specialists and researchers identify certain key characteristics associated with alcoholism. Characteristics linked to type 1 alcoholism include developing alcohol dependence only after turning 25, being introverted, consuming most alcohol in episodes or binges, only drinking in certain situations, lacking a tendency to seek out new sensations, typically avoiding fighting or other forms of antisocial conduct and frequently experiencing feelings of fear or guilt. In addition, when a person with type 1 alcoholism has an alcoholic parent, that parent is usually his or her mother. Characteristics linked to type 2 alcoholism include developing alcohol dependence before reaching age 25, being extroverted, consuming alcohol on a continual basis, drinking in a wide range of situations, having a tendency to seek out new sensations, participating in fighting or other forms of antisocial behavior and infrequently experiencing feelings of fear or guilt. When a person with type 2 alcoholism has an alcoholic parent, that parent is usually his or her father. Classification of alcohol-dependent people into types has only limited usefulness. Any given person may have a combination of traits normally only associated with type 1 alcoholism or type 2 alcoholism.

Alcoholism and Serotonin

Serotonin is a naturally occurring chemical in the brain and body that, among other things, helps people control their moods and avoid excessive emotional “highs” or “lows.” Some previous research findings have indicated that the processing of serotonin inside the brain may have an impact on several issues related to the odds of developing alcoholism and/or the potential consequences of alcoholism. These issues include an individual’s level of susceptibility to the basic intoxicating effects of alcohol consumption, the ability to avoid involvement in aggressive/impulsive behavior and the ability to cope with depression and other potentially damaging emotional states. Problems with serotonin processing may have a genetic basis; they may also stem from environmental factors encountered over the course of a person’s lifetime.

Are There Unique Brain Changes?

In the study published in Alcohol and Alcoholism, researchers from Sweden’s Karolinska Institutet and three Finnish institutions used a small-scale project to investigate the serotonin-related changes that occur in the brains of people affected by type 1 alcoholism and type 2 alcoholism. A total of 18 deceased individuals contributed data to this project. Eight of the decedents were affected by alcoholism while still alive; the remaining decedents did not have alcoholism. The researchers used advanced imaging technology to compare the serotonin processing systems in the brains of both groups of post-mortem study participants. They focused their examination on parts of the brain responsible for regulating such things as awareness in social situations and the relative ability to avoid responding to cues that promote alcohol consumption. The researchers concluded that the study participants affected by alcoholism had significantly slower serotonin processing systems than the study participants not affected by alcoholism. In some parts of the brain, the type 1 alcoholics and the type 2 alcoholics exhibited roughly equal amounts of processing problems. However, in one key area of the brain, only type 2 alcoholics had the observed difficulties with normal serotonin processing. Based on their findings, the study’s authors believe that people with type 2 alcoholism may have a unique inability to properly regulate their brain’s serotonin levels. They also believe that the effects of poor serotonin processing may make type 2 alcoholics unusually prone to antisocial behavior and cues that favor alcohol consumption. However, the authors note the small size of their project, as well as the preliminary nature of any research that connects serotonin processing to alcoholism. In light of these cautions, they call for further, broader research on this topic.

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