In line with prior research [e.g., 46], a measure of depressive illness severity was computed as the ratio of lifetime MDEs to the number of years since first depression onset, as a gauge of episode frequency. After computing this, three subjects were excluded from further analyses for having a depressive illness severity score > 3SDs from the mean. Correlations showed greater depressive illness severity was associated with greater beta-1 DMN-FPN connectivity (Spearman’s rank correlation rho=0.32, p=0.01, N=67; Fig. 2). This association remained significant when controlling for current depression severity on the MASQ GDD subscale (partial rho=0.29, p=0.02). This indicates that, whereas connectivity disturbances normalized in remitted individuals, for those with a history of depression, a more severe depressive illness course was associated with stronger high-frequency DMN-FPN connectivity.
