A patient cannot recall a distressing part of her past. Before revealing the answer, decide what distinguishes catathymic amnesia from dissociative amnesia.

Ask how broad the memory loss is, and specifically whether personal identity and general autobiographical memory are affected, or whether the gap is confined to one particular painful memory. Catathymic amnesia differs from dissociative amnesia in being narrower and more circumscribed, sparing personal identity and general autobiographical memory entirely; only a specific, closely linked painful memory is affected. Dissociative amnesia is broader, more sudden in onset, and capable of affecting identity itself, rather than being limited to a specific painful memory. The scope of what is lost, one narrow memory versus a wider swathe potentially including identity, is the key distinguishing detail.