Evaluating the evidence for repressed memory recovery in psychedelic contexts

Reports of resurfaced repressed memories during psychedelic experiences have circulated for decades and still emerge today. However, the veracity of repressed memories remains debated, and the mechanisms through which psychedelics might recover alleged repressed memories are unclear.

This scoping review aimed to provide an overview of the literature on repressed memory in the context of psychedelics. It examined how repressed memory was defined, which substances were predominantly discussed, which mechanisms were proposed to explain their effects, and whether these mechanisms were empirically supported.

A scoping review was conducted in line with PRISMA-ScR guidelines. Web of Science, PubMed, PsycINFO and Google Scholar were searched for relevant publications. Fifty-three sources met eligibility criteria. Data were charted on study design, psychedelic substance, definitions of repressed memory, results, and proposed mechanisms.

Most publications focused on lysergic acid diethylamide (LSD) in relation to repressed memory. Few sources provided a definition of repressed memory. Proposed mechanisms on how psychedelics might influence repressed memory included psychoanalytical reductions of defensive memory blockades and neurobiological alterations of executive control. However, empirical support for these mechanisms was limited.

The included literature did not offer a coherent explanation on how psychedelics could recover repressed memories, nor consistent evidence that they did so reliably. Future work should provide clear definitions of repressed memory in the context of psychedelics, test proposed effects of psychedelics on memory and executive control across multiple psychedelic substances, include placebo-controlled designs, and account for the potential occurrence of false memories.