on these drugs [5]. The severity of the dependence and resulting withdrawal symptoms is a major contributor to the addictive potential of opioid narcotics. Current strategies for treatment of opioid withdrawal are suboptimal; they rely on the administration of controlled substances (methadone and buprenorphine), or medications with significant hemodynamic side effects (clonidine). As it can lead to new approaches for prevention or treatment of addiction, identification of novel genetic factors affecting dependence on opioids is of great public health significance.
