When a patient is suffering from depression and considering medication, practically all physicians have the same go-to treatment: a selective serotonin reuptake inhibitor. Patients start on a low dose and slowly increase it. It may take weeks for the drug to work, if it works. If not, a cycle begins. Wean off the SSRI, wean onto a new medication. All the while, the patient must manage depressive symptoms along with any side effects of a medication, which, counterintuitively, can include suicidal thoughts.
This trial-and-error approach can exhaust and discourage patients, and too many failed trials could lead some to stop seeking treatment altogether.