[[seratonineserotonin|SeratonineSerotonin]] deplition<ref>Denk F, Walton M, Jennings K, Sharp T, Rushworth M, Bannerman D. Differential involvement of serotonin and dopamine systems in cost-benefit decisions about delay or effort. Psychopharmacology. 2005;179: 587– 596.</ref> and [[NMDA]] antagonism <ref>Floresco SB, Tse MTL, Ghods-Sharifi S. Dopaminergic and glutamatergic regulation of effort-and delay-based decision-making.</ref>promote impulsivity