Figure 2.

The cross-lagged longitudinal model illustrates the reciprocal causal relationship between depression and anxiety over time and whether the depression symptom relief predicts subsequent anxiety symptom improvement, and vice versa during acute electroconvulsive therapy (ECT). Rectangles represent the indices of depression symptom severity and anxiety symptom severity. Circles with an e are called error terms (i.e., e1–e8 = error term), which represent the effect of unexplained variation on the indices. Unidirectional arrows signify direct effects and bi-directional arrows represent correlations, *P < .05, **P < .01.