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Meanwhile, the observation that depression caused a decrease in appetite and weight loss used to be more common, but that came before 29 flavours of medicinal Dorito's.

This reminds me of the bland foods not registering in obese animals/people stuff. In rodents, one of the measures they use for depression is the animal's liking for sweet. Not liking is interpreted as anhedonia, a deficit in feeling pleasure.

Quote:

Circumstances in which serotonin (5-HT) and noradrenaline (NA) are altered, such as in anxiety or depression, are associated with taste disturbances, indicating the importance of these transmitters in the determination of taste thresholds in health and disease. In this study, we show for the first time that human taste thresholds are plastic and are lowered by modulation of systemic monoamines. Measurement of taste function in healthy humans before and after a 5-HT reuptake inhibitor, NA reuptake inhibitor, or placebo showed that enhancing 5-HT significantly reduced the sucrose taste threshold by 27% and the quinine taste threshold by 53%. In contrast, enhancing NA significantly reduced bitter taste threshold by 39% and sour threshold by 22%.

http://www.jneurosci.org/content/26/49/12664

Can't find anything in mice right now, but there're a number of studies like this showing an increased sweet threshold in depressed humans, or this one that shows that antidepressives can decrease the sweet threshold. When rodents are given the sweet preference test, there's a set percentage sugar in the water, if the sweet threshold increases, it might no longer be able to even notice that the water's been sweetened, it's not that it wouldn't like sweet, if you added enough sugar to get up above the animal's sweet threshold.

I find the depression-->obesity idea fairly reasonable, I might be biased because I got my fattest during a mixed depressive/schizo/mania. My first psychotic episode was a doozy.

Self-medication? Compensation might be a better term. Suppose I can't enjoy the simple food that might have kept me slim. I might be living on ice cream and french fries--but that skinny, mentally balanced person over there might be perfectly happy eating food that should taste good enough to me, but doesn't, due to effects of depression.