Patent ID: 7606622

Claim:
An implantable device, comprising: a sensing channel configured to collect values of one or more physiological variables in a patient; circuitry configured to derive one or more depression parameters that are correlated with depression in a patient from the one or more collected physiological variables; a sensing channel configured to generate an electrogram signal representing electrical activity in a cardiac chamber; circuitry configured to measure and collect time intervals between successive intrinsic beats, referred to as a BB interval, and storing the collected intervals as a discrete BB interval signal, filtering the BB interval signal into defined high and low frequency bands, and determine the signal power of the BB interval signal in each of the low and high frequency bands, referred to as LF and HF, respectively; circuitry configured to compute a heart rate variability parameter as an LF/HF ratio; circuitry configured to detect depression based upon the one or more depression parameters, wherein the one or more depression parameters includes the computed LF/HF ratio; and, wherein the circuitry configured to detect depression is further configured to cause delivery of anti-depressive therapy when depression is detected.