Table 5.

Binary classifications between unipolar (MDD) and bipolar (BD) depressed patients (N = 44)

	Accuracy (%)	Sensitivity (%)	Specificity (%)	Positive predictive value	Negative predictive value	P‐value according to permutation tests
Support vector machines
Sad>neutral faces	68.2	63.6	72.7	0.700	0.667	0.028*
Happy>neutral faces	61.4	59.1	63.6	0.619	0.636	0.12
Sad>neutral faces and happy>neutral faces	65.9	63.6	63.6	0.667	0.682	0.045*
Sad>happy faces	75.0	63.6	86.4	0.820	0.704	0.008*
Gaussian process classifier
Sad>neutral faces	65.9	68.2	63.6	0.652	0.667	0.043*
Happy>neutral faces	56.8	59.1	54.6	0.565	0.571	0.263
Sad>neutral faces and happy>neutral faces	65.9	68.9	63.6	0.652	0.667	0.059
Sad>happy faces	79.6	81.8	77.3	0.782	0.810	0.002*

Sensitivity and specificity refer to the classification of bipolar depressed subjects. *Significant at statistical threshold P < 0.05.