Project Summary/Abstract Poor adherence to prescribed medications is a major public health problem across chronic illness such as severe mental illness (SMI), leads to increased risk of hospitalizations, costs up to $300 billion annually and is arguably one of the most important modifiable risk factors leading to poor outcomes. According to the World Health Organization, increasing adherence may have a greater effect on health than any improvement in specific medical treatments. We propose to test a remotely delivered version of Cognitive Adaptation Training (R-CAT) which uses environmental supports to bypass many of the problems people have in following through with medication even when they think it is the right thing to do for their illness. R-CAT is designed to bypass problems including, forgetting, distraction, problem-solving, motivation, and resources such as limited access to transportation. CAT delivered in person has been found to improve medication follow-though, reduce hospitalizations, and improve outcomes for individuals with SMI. R-CAT was developed to serve a larger number of individuals as well as those in rural settings, and includes individualized medication set up; text reminders; telephone staff to check in and assist in re-filling medication containers; mail-delivered supports (signs, customized pill containers, alarms, checklists), limited in-home visits and a series of participation prizes to improve habit formation and sustain good medication follow-through. We propose to randomize 266 managed care members to R-CAT or Treatment as Usual for 6 months and to follow them for 6 months after treatment ends. Medication follow-through will be assessed using unannounced in-home pill counts and claims data for refills. We will also measure symptoms, service use, and care costs. In addition, we will examine the mechanisms of action of R- CAT. The path model proposes that during treatment repetitive behavior performed at the same time, in the same way, every day in response to R-CAT cues (i.e., taking medication because of cues, alarms, text messages) leads to habit formation, increasing habit strength/automaticity. We propose that habit strength at the end of treatment then predicts maintenance of adherence. Improving adherence to medication may be one of the most important MCO-wide behavioral change targets. If successful, a remote, easy to deliver intervention such as R-CAT in managed care has the potential to improve adherence and outcomes for those with SMI and other chronic medical conditions and to substantially reduce the costs of care.