Table 2.

Subgroup analyses of CES on anxiety and depressive symptoms divided by primary and secondary anxiety.

	Improvement in anxiety symptoms scale (Hedges' g, 95% CI)	Improvement in depressive symptoms scale (Hedges' g, 95% CI)
Diagnoses
Primary anxiety	−1.218 (−1.468 to −0.968) P < 0.001, k = 3, n = 288	NA, k < 3
Secondary anxiety	−0.334 (−0.570 to −0.098) P = 0.006, k = 8, n = 504	−0.401 (−0.750 to −0.053) P = 0.024, k = 6, n = 379

CES, cranial electrotherapy stimulation; CI, confidence interval; k, number of trials; NA, not available.