David Happel has been appointed CEO of digital therapeutics developer Cognoa. Brent Vaughan, Cognoa’s co-founder and former CEO, will move into a role at venture capital firm Morningside Group, the Palo Alto, CA-based startup’s largest investor. He will also continue to advise Cognoa. Happel joins the company from Chrono Therapeutics, a digital health startup that developed a smoking cessation technology. Cognoa is developing digital products for diagnosing and treating behavioral conditions. Its first target is autism.