SDC tracks relapse in held-out patient
depression
REMISSION
To demonstrate the potential utility of the SDC in a clinical setting, we retrospectively analysed LFP data from one participant (P001) whose data were not included in training the classifier or the GCE. Thus, this participant served as an out-of-sample validation data point for the SDC as a depression state biomarker. P001 experienced a clinical relapse after 4 months in remission. P001 started the active stimulation phase with low HDRS-17 scores (less than 8) and had a sudden and sustained worsening of symptoms such that they were deemed a non-responder by week 16 (Fig. To demonstrate the similarity between HDRS-17 and the SDC in this out-of-sample participant, we compared the states indicated by HDRS-17 and the SDC. As the therapeutic response was at the beginning of the observation phase, it is not possible to use the criteria described above for ‘stable response’. Yet, if we consider the two states as ‘sick’ and ‘response’ denoting a change in HDRS-17 of less than 50% decrease and greater than 50% decrease (respectively), we find that the SDC state accurately predicts the HDRS state 75% of the time over the 24-week treatment course (