The Ink-Pot and the Palette

I agree that usually there is a psychological component to these behaviours, and that should be explored. However, what you described seemed less depressive and more chemically related, though with the tangle those things usually are it is hard to say which came first the egg or the chicken.
NPR did a whole segment at one point about a woman who totally ruined her family finances, lost the house ect, due to chemical imbalance and gambling addiction. As SOON as the chemicals (as I recall it did involve serotonin) were addressed the whole compulsion went away. Anyway it is good to go trace Arachne's thread through this mystery.