Suicidal tendencies can’t be categorized under any kind of mental disorders, but it is directly linked to several mental disorders that are responsible for creating hopelessness. Many of the mental disorders such as BPD, PTSD, depression, anxiety, schizophrenia, addiction and substance abuse etc. are responsible for development of such tendencies. There are certain symptoms that can be taken as warning signs for this. If a person is suffering from chronic unhappiness and mood swings and exhibits violent behavior.http://www.therapytribe.com/therapy/suicide_therapy.htm