Ignorance about mental health conditions is widespread, fostered by such reductionist psychiatric nonsense as "chemical imbalance" and the FDA's love of psychotropics and electrical gadgets. Depression is merely the "depressing" of feelings which can occur for one or more of several reasons: feeling that one's difficulties are great and giving up; the loss of ability through illness or injury or a beloved's death; or uncertainty about a decision and being "stuck." PTSD symptoms reflect the mind's healthy attempt to recover its equilibrium after an excessive stressful event(s).
The publicized benefits of drugs, which are often based on inadequate or faulty research, tend to be vastly exaggerated with their side-effects being downplayed. The ignorance of child psychological development and developmental psychopathology, widespread among doctors and the general public, motivates this search for miracle psychotropic solutions, and people getting "high" on dangerous substances instead of life.
Alcohol is an acquired taste best left unacquired. Having said this, the tendency to develop substance abuse problems derives from early childhood experiences during which basic ego capacities governing thinking, behavior, and others develop. Usually arising during adolescence, it isn't easy to treat since the pleasurable/quickly acting drug substance must be given up before psychotherapy can affect the needed change of damaged personality which aroused its use.
But personality tendency matters too, an instinctive need for self-control, and also learning from others that unfortunate and sometimes deadly things can happen when using such substances. Nuff said.