Statistical analysis
Hypothesis testing of changes in HDRS-17, SDC and individual features was performed using a one-sided Wilcoxon signed-rank test. The non-parametric test was chosen to account for the small sample size and inability to test for normality. The small sample size of the current study does not have sufficient power to test statistical significance at 0.05 in a two-sided test, even when the direction of changes is readily apparent. Therefore, we used a one-sided test with a threshold of 0.05 and also confirmed statistical significance in a two-sided test with a relaxed threshold of 0.1. Linear mixed models were used to test the association between the SDC and clinical assessment scores and the SDC and face classifier output (with the SDC as the fixed factor and participants as the random factor). Models were fitted using the ‘lmertest’ package