November 17, 2010

Binge Drinking Leads to Depression?

(Ivanhoe Newswire) "“ Teens who participate in binge drinking might be putting themselves at risk for mood disorders like anxiety and depression in adulthood.

A new Loyola University study has found that exposing rats to binge drinking permanently changed the system that produces hormones in response to stress. The disruption in stress hormones "might lead to behavioral and/or mood disorders in adulthood," senior author Toni Pak, PhD, and colleagues were quoted as saying.

"Exposing young people to alcohol could permanently disrupt normal connections in the brain that need to be made to ensure healthy adult brain function," Dr. Pak said.

Binge drinking is defined as a woman having at least four drinks or a man having at least five drinks on one occasion. Heavy binge drinkers can consume 10 to 15 drinks. Binge drinking typically begins around age 13 and peaks between 18 and 22, before gradually decreasing. Thirty-six percent of young people ages 18 to 20 reported at least one binge-drinking episode during the past 30 days, according to the Substance Abuse and Mental Health Services Administration.

The Loyola study examined the long-term effects of alcohol on the production of the stress hormone corticosterone in rats.

Humans and rats produce stress hormones in response to physical or psychological stress. Chronic exposure to cortisol and other stress hormones has been linked to depression, heart disease, and other problems.

In this study, researchers exposed adolescent rats to an 8-day binge drinking pattern. They had three days of alcohol binging, two days off, then three more days of binging. On binge days rats were injected with enough alcohol to raise their blood alcohol concentration to between 0.15 percent and 0.2 percent. This concentration would be about 2 to 2.5 times higher than the legal limit for humans. A control group of rats were injected with saline.

One month later, when the rats were young adults, they were exposed to one of three regimens: saline injections, a one-time alcohol injection or a binge-pattern of alcohol exposure. Alcohol is a form of stress, so the animals that had either a one-time or binge alcohol exposure produced more of the corticosterone. A more significant finding is that among rats that had received alcohol during adolescence, there was a significantly larger spike in corticosterone when they received alcohol during adulthood. These rats also had a lower base level of corticosterone than rats that had remained sober during adolescence. These findings suggest that alcohol exposure during puberty permanently alters the system by which the brain triggers the body to produce stress hormones.

SOURCE: The annual meeting of the Society for Neuroscience, held in San Diego on November 15, 2010