Depression treatments haven't changed much in decades. Here are the promising new drugs that could be more precise, work faster, and help more people.

• Advances in depression treatment have been rare over the past few decades.
• But biotech companies are looking for ways to improve treatments.
• While some are developing drugs that work faster, others are targeting subtypes of the disorder.

Depression is an incredibly common disorder that affects roughly 280 million people worldwide.

But treatments for mental-health illnesses, like depression, haven't changed much over the past few decades. An estimated one-third of patients who try antidepressant treatments don't see improvements in their symptoms.