One of the first studies that I came across more than 15 years ago when I first started dabbling in biochemistry was on the roles of serotonin and dopamine in "pathological curiosity" seen in some children, which was thought to often lead to "oppositional-defiance disorder" later on in their...
I have written before about the well-known tendency of people with depression, PTSD, and other traumatic disorders to ruminate and focus intensively on analyzing past events. This is one of the reason people with such conditions tend to abuse alcohol. In addition to temporarily lowering stress...