A method includes receiving sensor data at a processor from sensors of an external medical device. The sensor data corresponds to at least a first body parameter value for a patient and a second body parameter value for the patient. The method includes determining a first depression-indicative value based on the first body parameter value, a second depression-indicative value based on the second body parameter value, a depression detection value as a function of a first weight applied to the first depression-indicative value and a second weight applied to the second depression-indicative value, and a depression state based at least in part on a comparison of the depression detection value to one or more threshold values.