High Levels of Serotonin Found in People with Social Anxiety Disorder
People with social anxiety disorder produce too much of the neurotransmitter serotonin, not too little as was previously believed, according to a new study published in the online JAMA Psychiatry.
“Neurotransmission in social anxiety disorder is characterized by an overactive presynaptic serotonin system, with increased serotonin synthesis and transporter availability,” researchers reported.
Investigators used positron emission tomography to examine the rate of serotonin synthesis as well as serotonin transporter availability in 18 patients—half men and half women—with social anxiety disorder and 18 healthy control subjects matched for age and gender.
Participants with social anxiety disorder, they found, produced more serotonin in the amygdala, the fear center of the brain.
“Serotonin can increase anxiety and not decrease it as was previously often assumed,” said researcher Andreas Frick, MSc, a doctoral student at Uppsala University in Sweden.
Researchers observed nerve cells releasing serotonin, which attached to receptor cells. The receptor cells responded by pushing the serotonin back to the cells it originated from.
“Not only did individuals with social phobia make more serotonin than people without such a disorder, they also pump back more serotonin,” said Frick. “We believe that this is an attempt to compensate for the excess serotonin active in transmitting signals.”