Trazodone, the drug that officials say Navy Yard shooter Aaron Alexis was prescribed by Veterans Affairs, is a a generic antidepressant that is seldom used anymore to treat depression but is widely prescribed for insomnia, experts said.

“We use Trazodone to help people sleep,” said Gabriela Cora, a physician and longtime practicing psychiatrist in Miami. The drug is considered safer than many other widely prescribed sleep medicines because it doesn’t cause addiction and doesn’t require increased dosing over time, said Cora, a former researcher on mood and anxiety disorders at the National Institutes of Health.

“If you take 50 milligrams and get a good response one day, your body will continue to respond to that dosage” if you need to take it another day.

In higher dosages, the side effects would typically be increased drowsiness, weight gain, and water retention, she said.

“Honestly, it’s a very safe drug to use,” she said.