Behavioral sensitization involves the progressive increase of behavioral responses to psychomotor stimulants and provides a model for the intensification of drug craving and relapse alleged to underlie addiction in humans. Mechanisms related to sensitization may also contribute to schizophrenia and bipolar disorder. The phenomenon of behavioral sensitization has been observed for years. However, studies have only recently focused molecular or intracellular mechanisms associated with behavioral sensitization. The activation of PLA2 and cAMP signal transduction pathways within mesolimbic dopamine neutons, at the level of the nucleus accumbens and ventral tegmental area, may have a crucial role in the development of behavioral sensitization. However, few studies have directly studied the effects of PLA2 and cAMP on behavioral sensitization. Therefore, future research should address this issue. 61 references (Author abstract modified)