Synaptic plasticity in addiction

Drug addiction, defined as compulsive drug use despite serious negative consequences, has been one of the major social problems facing modern societies. A growing body of evidence suggests that drug exposure induces a series of adaptive changes within the brain reward circuitry, some of which are extremely long-lasting and which may mediate maladaptive emotion/reward learning and memory, thus leading to addiction. Here, we review recent findings concerning drug-induced neuronal plasticity occurring at excitatory synapses in the brain areas that make up the reward circuitry. Given that the synapse plays a critical role in neuronal plasticity, drug-induced synaptic plasticity may critically mediate the formation of drug-related memories and thereby, addictive behaviors.