Ok this one literally "tastes like neuroscience." (Oh ho ho, I kill me.)
Seriously though, this discovery that it may be possible to diagnose depression through altered taste may one day result in a clinically useful (if unconventional) 'depression test.' A group at the University of Bristol, who have published the study in the recent edition of the Journal of Neuroscience, found that the levels of the neurotransmitters serotonin and noradrenaline affect how a person perceives taste. These two neurotransmitters are also implicated in depression, and are potential pharmacological targets in treating depression with drugs. The molecules affect taste in different ways, so it may be possible to pinpoint which neurotransmitter is in inbalance, and correct that specific molecule through drug therapy.
During the trial, 'healthy' volunteers were given two anti-depressant drugs, which raised the levels of both chemicals in their brain. Increased serotonin levels appeared to improve sensitivity to sweet and bitter tastes, while increased noradrenaline levels appeared to improve sensitivity to bitter and sour tastes.
Their findings also indicate that depressed people have an overall diminished sense of taste, which may contribute to a lack of appetite that is often seen as a symptom of depression. Current drugs for depression are rather nonspecific drugs that affect levels of both serotonin and noradrenaline, however as drug therapies evolve to become more specific in their targeting, this test may prove very useful.
In traditional (Chinese) medicine, taste change is part of sign for diagnosis. Not only that, the color of tongue is also sign for diagnosis.
I wonder if there is any connection to craving. Folks who like salty or sweet.
While it might be useful for figuring out which neurochemical is lacking I wonder if it would be any use distinguishing clinical depression from non-clinical depression. Isn't the dulling of the senses symptom found in both the clinical depression and the more garden variety bad mood.
Hmmmm, maybe that explains why certain smells seemed more pronounced when I started taking ADHD meds (which raise norepinephrine levels).