The Role of 5-HT(2C) Polymorphisms in Behavioral and Psychological Symptoms of Alzheimer Disease

The majority of Alzheimer disease (AD) patients suffer from various psychiatric symptoms, such as depression, psychosis, and anxiety, at some point during the disease process. These symptoms are collectively known as the behavioral and psychological symptoms of dementia (BPSD). Using family studies, a genetic component to BPSD development in AD has been demonstrated. Research has therefore been undertaken to attempt to uncover these genetic susceptibility factors. Genes involved in neurotransmitter systems have been investigated, and the serotonergic system is of particular interest because evidence suggests it plays a role in many aspects of human and animal behavior, including aggression, hallucinations, delusions, depression, anxious behavior, and the regulation of appetite. Therefore the genes encoding components of this system make good candidates for susceptibility factors for BPSD. A variant within the serotonin receptor 5-HT2C gene has been investigated in a few interesting studies, which are reviewed here. Potential associations with psychosis, depression, anxiety, and appetite disturbances have been reported, although the degree to which this variation influences the manifestation of these symptoms may only be small.