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New Study Suggests Serotonin Can Increase Your Chances of Addiction

Although a lot of time has been spent studying dopamine, a “feel-good” neurological chemical, and its role in drug addiction, a new research project indicates that dopamine isn’t the only brain chemical we need to worry about.

According to the results of an intensive study, scientists now believe that serotonin can also increase the risk of drug addiction.

Uncovering the Serotonin Link

Drug addicted man sitting alone in a corridor

Serotonin is produced within the brain and is responsible for maintaining mood balance. Dopamine, on the other hand, is often associated with feelings of euphoria.

According to Sarah Bradbury, who led this study and recently graduated with her PhD in Psychology, the level of serotonin a person has during his or her first drug experience can either increase or decrease the chances of becoming addicted.

“People develop drug addiction due to changes in specific brain systems following repeated drug use, but not all drug users become addicted,” she explained. “Another brain chemical, dopamine, seems to be the critical determinant of drug addiction during this phase.”

Bradbury suggests in her findings that, once a person’s drug use increases, serotonin levels decrease. And, although her research focused mainly on MDMA and cocaine abuse, she believes the results are likely relevant when addressing a broad spectrum of drug addictions.

Supporting Research

Bradbury’s conclusions are in line with several other recent research projects. For example, a December 2011 study from researchers at Vanderbilt University found a correlation between recreational ecstasy use and sustained increases in serotonin receptor density. Essentially, the data indicates that ecstasy use can spark serotonin depletion and severe depression once the drug exits a person’s system.

According to Ronald L. Cowan, MD, PhD, even when a person stops using ecstasy, damage done to the serotonin receptors is permanent.

Although ecstasy has been used therapeutically as a means of helping patients with autism or post-traumatic stress disorder, Cowan warned that recreational use of the drug is far different than its use in a medically supervised and controlled setting.

The Dopamine Connection


Serotonin certainly isn’t the only brain chemical that scientists have linked to a person’s risk of addiction. A study published last July in the journal Proceedings of the National Academy of Sciences presented data that showed dopamine levels can affect susceptibility to addiction.

Researchers found that chronic marijuana use dampened the brain’s dopamine and its subsequent reaction to stimulants. This caused the subjects to experience a much lower sense of reward or motivation from doing things that most people find pleasurable.

In stark contrast to the carefree and pleasurable effects often associated with marijuana use, lower dopamine levels in the brain tend to leave users feeling more irritable, moody and restless.

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