HTR1B as a risk profile maker in psychiatric disorders:a review through motivation and memory

Purpose Serotonin receptor 1B (HTR1B) is involved in theregulation of the serotonin system, playing different roles inspecific areas of the brain. We review the characteristics ofthe gene coding for HTR1B, its product and the functionalrole of HTR1B in the neural networks involved inmotivation and memory; the central role played by HTR1Bin these functions is thoroughly depicted and show HTR1Bto be a candidate modulator of the mnemonic andmotivationally related symptoms in psychiatric illnesses.Methods In order to challenge this assessment, we analyzehow and how much the genetic variations located in thegene that codes for HTR1B impacts on the psychiatricphenotypes by reviewing the literature on this topic.Results We gathered partial evidence arising from geneticassociation studies, which suggests that HTR1B plays arelevant role in substance-related and obsessive compulsivedisorders. On the other hand, no solid evidence for otherpsychiatric disorders was found. This finding is quitestriking because of the heavy impairment of motivationand of mnemonic-related functions (for example, recallbias) that characterize major psychiatric disorders.Conclusions The possible reasons for the contrast betweenthe prime relevance of HTR1B in regulating memory andmotivation and the limited evidence brought by geneticassociation studies in humans are discussed, and somesuggestions for possible future directions are provided.