In satate of addiction, when the the concentration of the [http://en.wikipedia.org/wiki/Receptor_%28biochemistry%29 receptors] for pleasure signals is low, people will be more attracted to plesure, and will be ready to take more risks. [[Dopamine]] is a mediator of plesure, and Dopamine agonists are used, thet can cause pathological gambling behavior<ref>Gallagher DA, O’Sullivan SS, Evans AH, Lees AJ, Schrag A. Pathological gambling in Parkinson’s disease: Risk factors and differences from dopamine dysregulation An analysis of published case series. Movement Disorders. 2007;22: 1757– 1763.</ref>.