Two hits or two misses? A critical comment on a combined psychological and biological origin of dissociative amnesia and repressed memory

Convertino et al. (2025) and Nachson (2025) both stated that biological substrates can be correlated to behaviour. Additionally, Convertino et al. noted that correlation does not imply causation. This issue concerning causation is imperative. Neuroscientific research cannot conclude whether detected neurological substrates have a causal link with dissociative amnesia/repressed memory (e.g. Taïb et al., 2023). Nonetheless, Markowitsch and Staniloiu (2025) claimed that organic brain damage is not in opposition to dissociative amnesia. They proposed the two-hit hypothesis referring to ‘an additive or synergistic interaction between psychological and physical incidents’ (Staniloiu & Markowitsch, 2014, p. 231) to explain certain dissociative amnesia cases. According to them, ‘physical incidents provide psychological or biological grounds for the development and maintenance of dissociative amnesia’ (Staniloiu & Markowitsch, 2014, p. 232). By this view, being hit on the head during a robbery (biological cause) could lead to psychological trauma and combined produce dissociative amnesia. We are sceptical that the two-hit hypothesis is a sound hypothesis. First, this hypothesis means that whatever the antecedent (physical, psychological), traumatic memory loss can almost always be labelled dissociative amnesia. This renders the concept of dissociative amnesia/repressed memory overgeneral and unfalsifiable. Second, the two-hit hypothesis does not delineate under which conditions such interactions can occur nor what mechanism is involved. Thus, it is not a hypothesis but merely a description of factors potentially underlying traumatic memory loss (Roberts et al., 2013). Proposing that two hits cause traumatic memory loss, while there is no causation, is a miss in this field. Henry Otgaar: Conceptualization; formal analysis; methodology; project administration; visualization; writing – original draft; writing – review and editing. Mark L. Howe: Writing – original draft; writing – review and editing. Lawrence Patihis: Writing – original draft; writing – review and editing. Ivan Mangiulli: Formal analysis; writing – original draft; writing – review and editing. Olivier Dodier: Writing – review and editing. Rafaële Huntjens: Formal analysis; writing – review and editing. Elisa Krackow: Formal analysis; writing – review and editing. Marko Jelicic: Writing – review and editing. Steven Jay Lynn: Writing – review and editing.