Devices to treat depression haven't had any big market breakthroughs. But key to achieving that is to show that they are a viable alternative to drug therapies--and that their impact can show a sustainable treatment benefit. Malvern, PA-based startup Neuronetics, which almost a year ago nabbed a $34 million Series F financing led by major strategic investor GE Ventures, recently published data on its NeuroStar TMS Therapy device showing that it can have a sustainable benefit for some patients--even without medication. Researchers seem likely to use the study to keep working to come up with an appropriate maintenance dose to support patients after intensive treatment. The study appeared in the journal Brain Stimulation ; it found that some nonmedicated depressed patients who responded to noninvasive transcranial magnetic stimulation (TMS) with the NeuroStar device for 6 weeks were able to sustain that response with a monthly dosage.