Medical illnesses are all much lower than any of these. One of the highest-risk periods for suicide is when patients are actually recovering from depression. Suicide is more common in highly creative or successful writers, artists, scientists and businessmen. In these folks most are related to depression, manic-depression, or alcoholism. There have been more than thirty family studies of suicide.
Violent suicide tends to be likely in families with a strong history of suicide.
Particularly interesting are the Amish. Also, they keep extensive medical records that can go back thirty generations. Three fourths were in just four families. They were clustered in families with mood disorders. Most who did it were married, with children, and in the prime years of life.