Depressed people are known to have fewer of the ‘feel-good’ receptors for serotonin.
Jon-Kar Zubieta, MD, PhD, University of Michigan, reports that depression is rooted in genetic and molecular factors and are unique for each individual. Using PET (positron emission tomography) scans, Zubieta studied patients who met the criteria for major depression, but had not yet received treatment for it. Those scans were compared with scans of non-depressed volunteers.
Serotonin levels were linked to depression as were the ‘feel-good’ (5HT1a) receptor concentrations. The worse the subject scored on the depression assessment the fewer ‘feel-good’ receptors they had. He also found that there was a direct relationship between the effectiveness of medication used to treat depression and the number of ‘feel-good’ receptors. The fewer the ‘feel-good’ receptors the less likely medication was going to relieve signs of depression.