Drug Combination Leaves Users Vulnerable to Addiction

May 8, 2009

Mixing certain recreational drugs, such as alcohol and ecstasy, can make people more vulnerable to addiction. Since 2000, there’s been a considerable increase in reported usage of this drug combination, based on emergency room findings and surveys.

Byron Jones, professor of biobehavioral health and pharmacology in Penn State’s College of Health and Human Development, has been studying the neurological effects of taking these drugs. He has found some interesting data, which he recently presented at the University of Central Lancashire in Preston, England.

“People don’t typically use ecstasy compulsively; it’s more like a weekend drug,” says Jones. “But we’re still worried that this combination can promote addiction.”

Alcohol and ecstasy affect the brain by increasing the release of different chemicals: alcohol increases the release of dopamine in the brain, and ecstasy increases the release of serotonin. Both drugs are associated with the brain’s reward system, which is involved with pleasurable feelings, and memories of pleasurable feelings that can influence people to repeat specific behaviors.

When taken separately, each drug produces a certain increase of each chemical. However, when taken at the same time, the result is not as simple as adding the effects of each—the amount of dopamine released by the combination is far greater than either drug would produce alone.

Jones and his colleagues at University Louis Pasteur in Strasbourg, France, and the University of Freiburg in Freiburg, Germany, have been measuring the effects of the drugs in rats. The rat brain uses similar neurotransmitters as humans (for example, dopamine and serotonin), which gives a reliable model of how the drug affects the human brain.

Jones found that the drug combination affected the animals’ desire to be in one specific place, which is known as conditioned place preference. The rats were placed in an environment in which they could choose between two rooms. Rats who received only one drug, or neither, regularly spent time in both rooms. Rats who received both drugs in combination, however, spent their time in only one room—the same room they received the drug combination in.

“It’s as if they were waiting for more,” says Jones.

The drug combination increased physical activity in subjects, to nearly three times the physical activity produced by ecstasy alone (which already increases physical activity).

Jones also found that the drug combination is problematic to the brain, based on the typical frequency with which people report they take the drug combination.

“We wanted the experiment to mimic the fact that people don’t typically take ecstasy every day,” says Jones. “So, we allowed a few days between injection times in certain groups. We found that this increased the effects of the drugs. This means that the reward system is activated more intensely, which could push people to use the combination more, to achieve that same pleasurable feeling.”

Using his research, which is funded by University Louis Pasteur, Jones hopes to educate the public with the neurological danger imposed and implications for addiction, when using alcohol and ecstasy in combination.


Editors: For additional information, please contact the College of Health and Human Development Office of College Relations at 814-865-3831 or healthhd@psu.edu.