No one saw it coming.
Neither Alyssa Weaver's parents, nor her classmates at Northwestern University, had any inkling the young woman with the infectious, high-pitched giggle was contemplating suicide.
Until it was too late.
Terri and Gordon Weaver have tried to make sense of that in the days since Nov. 21, when Alyssa ended her life. She was the salutatorian in Maury High School's Class of 2010. She'd been studying abroad for one semester in London through a Northwestern program.
"All she had to do was say anything, and I would have been on the next plane," Terri Weaver told me this week.
Signs of depression include irritability, restlessness and persistent anxious or "empty" feelings. Unfortunately, those signs might not be readily apparent, even to friends and family. That's why it can be so frustrating.
Alyssa's parents said she was on a mild medication for anxiety. She'd been tested. She'd talked to therapists over the years.
However, Terri Weaver said, everything suggested the high-achieving student was coping well in college.
Alyssa was a 20-year-old junior. She majored in art history and had a minor in chemistry. The campus newspaper said she was a member of a Northwestern University sorority and a boxing team. She took part in other activities, too, just as she'd done at Maury.
In September, Alyssa's family spent nearly two weeks together in Europe. After the parents returned to Norfolk, they frequently Skyped with her.
And on the day before she died, Gordon Weaver said, Alyssa had connected with her parents by email. She was planning a Thanksgiving menu with fellow students in London.
Everything seemed so ordinary.
"I really felt strongly that Alyssa died because she was in a... dark place and didn't let anybody in," Terri Weaver said, her voice cracking.
Brennan Suen, who studied in London, told The Daily Northwestern that several students - including Alyssa - had enjoyed their trip together to Germany this fall. "We were laughing the whole time, and she was so positive and so fun," he said. "I mean, no one had any idea...."
Most of us know that mental illness can strike people regardless of age, gender or race. In fact, 1 in 4 adults suffer from a mental disorder. Left untreated, depression, schizophrenia and other disorders can be as debilitating as heart disease, cancer or diabetes.
For sufferers, it's not simply a matter of "willing" themselves to get better. The National Institute of Mental Health says long-standing theories about depression suggest "that important neurotransmitters - chemicals that brain cells use to communicate - are out of balance." Medication and counseling can help.
It's critical that we stop the stigma surrounding mental illness, recognize the signs and help those suffering.
Roughly 100 Americans kill themselves every day, according to the Centers for Disease Control and Prevention.
As likely as not, someone close to you fights mental illness. Possibly in secret, possibly in shame.
Terri and Gordon Weaver know they can't get their daughter back.
But maybe their story will help you save someone you love.