Near the student union in the heart of campus, the Student Health Center building dates from the days when a serious undergraduate health problem was mononucleosis. But the hiring of Judy Esposito, a social worker with experience counseling Sept. 11 widows, to start a triage unit three years ago was a sign of the new reality in student mental health.

At 9 a.m. on the Tuesday after the campus’s very busy weekend, Ms. Esposito had just passed the Purell dispenser by the entrance when she noticed two colleagues hurrying toward her office. Before she had taken off her coat, they were updating her about a junior who had come in the previous week after cutting herself and expressing suicidal thoughts.

Ms. Esposito’s triage team fields 15 to 20 requests for help a day. After brief interviews, most students are scheduled for a longer appointment with a psychologist, which leads to individual treatment. The one in six who do not become patients are referred to other university departments like academic advising, or to off-campus therapists if long-term help is needed. There are no charges for on-campus counseling.

This day the walk-ins included a young man complaining of feeling friendless and depressed. Another student said he was struggling academically, feared that his parents would find out and was drinking and feeling hopeless.

Professionals in a mental health center are mindful of their own well-being. For this reason the staff had planned a potluck holiday lunch. While a turkey roasted in the kitchen that serves as the break room, Ms. Esposito helped warm up candied yams, stuffing and the store-bought quiche that was her own contribution.

Just then Regina Frontino, the triage assistant who greets walk-ins at the front desk, swept into the kitchen to say a student had been led in by a friend who feared that she was suicidal.

Ms. Esposito rushed to the lobby. From a brief conversation, she knew that the distraught student would have to go to the hospital. The counseling center does not have the ability to admit suicidal or psychotic students overnight for observation or to administer powerful drugs to calm them. It arranges for them to be taken to the Stony Brook University Medical Center, on the far side of the 1,000-acre campus. The hospital has a 24-hour psychiatric emergency room that serves all of Suffolk County.