PROJECT SUMMARY While cardiovascular disease remains a significant burden in the U.S., effects are particularly pronounced in people with mental disorders such as bipolar disorder (BD). Medical complications and early mortality in those with BD and hypertension is often associated with poor medication adherence and sub -optimal engagement in care. However, medication non-adherence among such individuals and its negative impact on both cardiovascular and mental health is a potentially modifiable problem of critical public health importance. The proposed study, written in response to PA-18-722: Improving Patient Adherence to Treatment and Prevention Regimens to Promote Health, will evaluate the effects of a personalized patient-centered adherence m-Health intervention called Individualized Texting for Adherence Building-Cardiovascular; iTAB-CV (iTAB-CV) on adherence to antihypertensive medications and systolic blood pressure in people with BD. In common with many individuals with mood symptoms, BD patients have cognitive and functional impairment that need adherence approaches that go above and beyond standard education. Effective approaches should help engagement in care for both physical and mental health. iTAB-CV is delivered on a mobile phone via Short Message Service (SMS) and is based on a modified version of the Attitude -Social Influence-Efficacy (ASE) model to target both intentional and non-intentional non-adherence. To change and sustain adherence in this and similar populations, one must address attitudes, self-efficacy, and prospective memory deficits to form the habit of medication taking. In a pilot trial of iTAB-CV, participants were highly engaged, with 100% retention over 3 months and showed significant improvement in adherence, reduction in systolic blood pressure (SBP), and improved psychiatric symptoms. This project will be conducted as a 12-month prospective 2-stage randomized controlled trial comparing iTAB-CV + Self-Monitoring of blood pressure, mood, and medication taking (n=100) to Self-Monitoring alone (n=100). The primary outcome is adherence to antihypertension medication as measured by the self-reported Tablets Routine Questionnaire (TRQ) and validated with objective automated pill caps (eCAP) and systolic blood pressure while secondary outcomes include adherence to psychiatric medication and psychiatric symptoms. iTAB-CV participants will be re- randomized to low and high frequency booster sessions to explore whether dose (frequency of text) moderates longer-term outcome, to investigate habit strength as a mediator of adherence and identify variables that enhance or impede adherence. We will also employ an advisory board made up of key stakeholders including patients, family members, providers, and administrative staff who can help inform how the intervention might fit into existing clinical workflows. iTAB-CV has potential to advance care for people with poorly controlled hypertension and mental health comorbidity. The practical, m-Health delivery format will enhance suitability for broad scale-up in future hybrid implementation-effectiveness trials.