[Kryptid (OP)]

From what I've learned, mental disorders are usually classified into three types: psychosis (delusions, hallucinations, generally out of contact with reality), psychopathy (violent, remorseless, deviant, antisocial), and neurosis (anxiety, compulsiveness, obsessiveness).

When a person who was originally sane "goes insane" due to some stressful event (such as torture, prolonged isolation from others, etc.), what kind of mental disorder do they acquire? Is it one of the above-mentioned types, or perhaps some combination of them? Does it vary depending on the specific circumstances? Is there a difference between those who are "naturally" insane and those who "become" insane? Can those driven to insanity regain sanity over time?

Or is "going insane" something of a misleading statement? Perhaps you cannot go "truly" insane from stress but rather just develop some other mental problems not akin to true insanity?

[RD]

When a person who was originally sane "goes insane" due to some stressful event (such as torture, prolonged isolation from others, etc.), what kind of mental disorder do they acquire?

That sounds like PTSD ... http://en.wikipedia.org/wiki/Post-traumatic_stress_disorder

[Chemistry4me]

Yep. Sounds like PTSD.