Taken straight from the “Medication Guide: Antidepressant Medicines, Depression, and other Serious Mental Illnesses, and Suicidal Thoughts or Actions” which comes with my antidepressant prescription:
Depression and other serious mental illnesses are the most important causes of suicidal thoughts and actions. Some people may have a particularly high risk of having suicidal thoughts or actions. These include people who have (or have a family history of) bipolar illness (also called manic-depressive illness) or suicidal thoughts or actions. (emphasis added)
So, apparently, the people most at risk for having suicidal thoughts or actions are people who have suicidal thoughts or actions. Very helpful. Thanks.