People with severe schizophrenia who have been isolated, withdrawn and considered beyond help can learn to become more active, social and employable by engaging in a type of talk therapy that was invented to treat depression, scientists reported on Monday.

These new findings suggest that such patients have far more capability to improve their lives than was previously assumed and, if replicated, could change the way that doctors treat the one million patients for whom the disorder is profoundly limiting.

The therapy — a variant of cognitive behavior therapy, which focuses on defusing self-defeating assumptions — increased motivation and reduced symptoms. In previous studies, researchers have used cognitive techniques to help people with schizophrenia manage their hallucinations and sharpen their attention and memory. The new study is the first to rigorously test using the therapy to combat so-called negative symptoms — the listlessness, exhaustion and emotional flatness that trap many people in solitary lives, playing out their days smoking in front of the TV or holed up in their homes.

Dr. Bob Buchanan, a psychiatrist at the University of Maryland School of Medicine who was not involved in the study, said the results looked impressive. “This is a group of patients who have tried just about everything — drug treatments as well as psychosocial ones — and many clinicians and systems of care have essentially given up on them. If there’s an intervention out there that can make a difference, I think that’s an incredibly important development.”