Why Anti-Depressant Zoloft Works Best for Later Onset Alcoholism

SSRI pill (Zoloft) pack in bowl on table
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One of the ways that alcohol can affect the brain is by damaging the functioning of serotonin, a chemical that influences mood, sleep, appetite, temperature regulation, and mood.

Consequently, people with alcohol use disorders often report problems with depression and anxiety. Their health care providers will typically prescribe selective serotonin reuptake inhibitors to help them maintain optimal levels of serotonin.

"SSRIs are the most widely prescribed class of anti-depressants," said William Dundon, senior research investigator in the department of psychiatry at the University of Pennsylvania School of Medicine. "SSRIs work by affecting the level of serotonin in the brain and elsewhere in the body. In the brain, serotonin is thought to influence mood, emotions, sleep, appetite, and temperature regulation."

Research has found, however, that SSRIs—such as sertraline (Zoloft)—do not work well for some people with alcohol use disorders.

Zoloft Doesn't Work for All Alcohol Use Disorders

To determine why SSRIs help some patients with alcohol use disorders and not others, Dundon and his colleagues examined two categories of alcohol dependence defined by researcher Thomas Babor of the University of Connecticut.

Babor divided individuals with alcohol problems into two groups, Type A and Type B. Type A alcohol dependence is environment-based and generally occurs later in life, while Type B alcohol dependence is genetics based and arises early in life.

According to Babor's research, Type B alcoholism tends to have a greater adverse impact than Type A alcoholism. Generally speaking, Type B alcoholism is more severe and higher risk than Type A alcoholism.

During the study, 100 people with alcohol use disorder were given a three-month course of either sertraline (200 mg/day) or placebo capsules and individual therapy based on the Alcoholics Anonymous framework. The 55 people with Type A alcohol dependence and the 45 people with Type B alcohol dependence were later interviewed about their alcohol consumption.

Zoloft Helps Type A Alcohol Dependence

The researchers compared monthly alcohol consumption for the six months following treatment to alcohol consumption during the last month of treatment. Dundon's study found that people with Type A alcoholism had a better treatment response to Zoloft than people with Type B alcoholism.

During the six months following treatment, the Type A group treated with Zoloft maintained their gains, while the Type B group did not.

Maintained Positive Results

Specifically, the Dundon study found:

  • Type A people with alcohol use disorder who took Zoloft maintained, for at least six months after treatment ceased, the positive results they obtained during treatment
  • Type B people with alcohol use disorder treated with Zoloft continued to show no pharmacotherapeutic benefits during the six-month period following treatment.
  • For Type B people with alcohol use disorder, heavy drinking actually increased during the six months following treatment with Zoloft.

SSRIs Are Not Appropriate for Type B Alcohol Dependence

"We appear to have identified a subgroup of alcoholics, Type As, who responded well to sertraline during treatment and maintained their gains over a six-month period after ending treatment," said Dundon.

"However, there is another subgroup, Type Bs, for whom SSRIs may not be appropriate. This subgroup seemed to maintain their gains from the AA-based individual therapy only if they had not received sertraline," he said.

The reason the researchers examined Babor's two types of alcohol dependence is due to previous research that suggested that there were differences in serotonin metabolism between the two groups. The Type B group were found to have more abnormalities in serotonin metabolism, in the earlier study, and it was thought that group would be more likely to respond to Zoloft treatment. However, the Type B group did worse on the SSRI treatment and during the six-month, post-treatment period.

Implications for Alcohol Use Disorder Treatment Plans

The researchers concluded that being able to determine whether people with an alcohol use disorder entering treatment are either Type A or Type B could be helpful in developing a treatment plan.

"I think our study clearly suggests that there may be ways to subtype alcoholics and that these different subgroups of alcoholics may respond differently to the same treatment," Dundon said. "Numerous classification schemes have been proposed to differentiate types of alcoholics. Our study supports the usefulness of the Babor Type A and Type B classification system."

Study Confirms Babor's Type A and B Alcohol Dependence

Later research by the Public Health Institute and the University of California, San Francisco using data from the National Epidemiologic Survey on Alcohol and Related Conditions confirmed that Type A and Type B alcohol dependence exist in real life.

The study found that Type B alcohol dependence in the general population, compared to Type A, led to higher alcohol severity and more co-occurring drug, mental, and physical health problems.

The Type B group were twice as likely to be alcohol dependent three years later and more likely to be heavy drinkers and drug dependent.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area.

For more mental health resources, see our National Helpline Database.

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