I think that there is some truth in what both of you say; however, I'm not satisfied that there are not other factors involved:
Mental health - particularly mood disorders such as depression
Combined mental health and substance abuse issues
Hopelessness/Helplessness
Impulsive and/or aggressive tendencies
Barriers to accessing mental health services
Loss (relationships, health, identity status)
Physical, emotional and sexual abuse
Legal issues/arrests/incarceration
Sexual identity conflict
Does anyone else think that these might be contributing factors?