A reason people do commit suicide by mental disorders. Such as bipolar and other thing like that is very serious when it comes to thinking about suicide and nothing else, accept committing suicide so yeah that can happen especially with mental disorders. No offense not trying to be offensive or disrespectful.
In general, people try to kill themselves for six reasons: They're depressed. This is without question the most common reason people commit suicide. Severe depression is always accompanied by a pervasive sense of suffering as well as the belief that escape from it is hopeless.