MHT has considerable potential to reduce rates of inpatient re-hospitalization for mood disorders. EMA methods have previously shown to be superior to standard patient follow-ups for detecting medication response in depression14 or days ill in bipolar disorder18. While numerous previous studies have looked at general patterns of recurrence and prognostic factors in the long-term course of major depressive disorder4;23;24;27 and bipolar disorder, none have looked at using EMA or MHT data to monitor for signs of imminent relapse in individual cases. The rich data stream provided by MHT will allow us to do this for the first time, similar to how ECG telemetry is routinely used for diagnostic and prognostic purposes. Doing so will enable clinicians to trigger early community- or outpatient-based interventions, thus reducing the likelihood of relapse and / or hospitalization.