Cutting is actually a mental disease. When someone cuts themselves with a addictive personality it lights up the same part of the brain as taking heroine or cocaine. Addiction is considered a mental disease therefor cutting=mental disease.
Actually self harm is not a mental disease, it is related to several however it Is not classified as one itself
It is not the self harm that makes it a mental disease, it is the dopamine rush they receive when doing so that excites them That does
Yes it could By your logic games like counter strike which are fast paced games that send dopamine into your brain are drugs there is no argument about that. This directly leads into wars in kaw that some people find fast paced and therefore get extremely excited. The same excitement occurs when you finally get that awesome equip you've been hunting for days or you finally get that building upgrade. It all sends dopamine into your brain therefore by your logic Kaw and many over games are drugs.