When the grooves of self-reflective thinking deepen and harden, the ego becomes overbearing. This is perhaps most clearly evident in depression, when the ego turns on itself and uncontrollable introspection gradually shades out reality. Carhart-Harris cites research indicating that this debilitating state of mind (sometimes called heavy self-consciousness or depressive realism) may be the result of a hyperactive default mode network, which can trap us in repetitive and destructive loops of rumination that eventually close us off from the world outside.
