There's no quick fix for severe depression.
Although antidepressants like Prozac have been around since the 1970s, they usually take weeks to make a difference. And for up to 40 percent of patients, they simply don't work.
As a result, there are limited options when patients show up in an emergency room with suicidal depression.
The doctors and nurses at Ben Taub General Hospital in Houston say they see this problem every day.
You can get a sense of what they're up against by visiting the cavernous, bustling emergency center at Ben Taub, which is part of the massive Texas Medical Center. More than 100,000 patients a year get emergency care here, and about 5,000 of them need psychiatric evaluation.
The hospital's 24-hour Psychiatric Emergency Center gets a steady stream of people with suicidal depression, says Charlzetta McMurray-Horton, who is in charge of mental health nursing.