The pathway that leads to addiction in Valium users is a separate pathway to its therapeutic effects, giving hope for future non-addictive drugs.
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PARIS: Scientists have figured out why people get hooked on a class of prescription drugs that includes Valium, along with other antidepressants, muscle relaxants and sleeping pills.
The findings, reported in the British journal Nature, open a path to developing new treatments that can ease symptoms without causing dependence, the researchers hope.
Opium, heroin and cannabinoids are addictive because they activate a neural circuit that boosts levels of a reward-giving brain chemical called dopamine.
Stimulating reward chemical dopamine
The molecular pathway they use to unleash dopamine is well known.
Benzodiazepines – which include Valium, Xanax, Librium, Ambien and other well-known drugs – likewise stimulate the dopamine system, but until now how they did this was unclear.
In a series of experiments on mice, a team led by Christian Luscher at the University of Geneva say they have solved the mystery.
Benzodiazepines switch on a intermediary neurotransmitter known as gamma-aminobutyric acid, or GABA, and increase dopamine levels, resulting in the signature craving of addiction, they found.
Pathway to addiction not related to therapy
The pathway that has been uncovered does not have an effect on benzodiazepines' therapeutic effects.
As a result, it should be possible to design new drugs that deliver the same benefits but without inducing addiction, said the researchers.
The work "is a landmark for the field," noted Arthur Riegel and Peter Kalivas of the Medical University of South Carolina in Charleston.
"These authors are the first to identify a molecular mechanism contributing to benzodiazepine abuse," the pair wrote in a commentary, also in Nature.
