Memory, Mood, and Identity: Episodic Memory Impairments and the Loss of Diachronic Unity in Depression

Abstract

Tulving proposed that episodic memory is not merely a record of past events, but a form of mental time travel, characterized by autonoetic consciousness (Tulving, 2005). From this view, episodic memory allows for the diachronic unity of self by preserving the subjective sense that “I” was the one who lived the remembered experience. In contrast, Conway and Pleydell-Pearce argued that continuity of self is actively constructed by the conceptual self, which selects and distorts past experiences to maintain a coherent narrative (Conway, 2005; Conway & Pleydell-Pearce, 2000). Despite offering opposing accounts of how self-continuity arises, both frameworks converge on a central claim: that episodic memory plays a constitutive role in maintaining a unified sense of self over time. 

But what happens when this system is disrupted? In depressive disorders, episodic recall becomes overgeneral and biased toward negatively valenced content (Williams et al., 2007). Such cognitive distortions may not merely reflect depressive symptoms, but instead contribute to a fragmented self-concept. Given the role of episodic memory in maintaining a continuous sense of self, I argue that the episodic memory impairments associated with depression disrupt continuous self-concept. Moreover, alterations to sleep architecture in major depressive disorder (MDD), including reduced slow-wave sleep (SWS) and disrupted rapid eye movement (REM) patterns, are thought to exacerbate cognitive biases in episodic memory (Harrington et al., 2023). Thus, interventions targeting sleep quality hold promise for alleviating cognitive distortions and strengthening self-continuity in depression.