The lesson for us in a bipolar disorder patient comorbid with dissociative amnesia

To the Editor

Amnesia is a state when memory and learning are highly affected compared with other cognitive functions in an alert and responsive patient. Amnesia includes two categories: with or without medical lesions. Terms used to describe medically unexplained amnesia includes ‘psychogenic’, ‘dissociative’ and ‘functional’. In Diagnostic and Statistical Manual of Mental Disorders–Fifth Edition (DSM-V), the term ‘dissociative amnesia’ (DA) is favored. We report a DA case with underline of bipolar disorder to elucidate clinical wisdom. This report has obtained a signed release from the patient authorizing publication.

A 38-year-old female with an 8-year bipolar disorder history was brought to the emergency department by her anxious husband for suddenly considering him a stranger intruding her house after an intense row. She denied all memories of marriage and insisted in remaining single. However, other memories of the same period were intact without disruption of personal identity. She denied history of memory loss, medical illness, substance abuse, head trauma, or seizure. Physical survey included brain magnetic resonance imaging was normal. She was admitted to the psychiatric ward. On admission, Young Mania Rating Scale scored 5, Beck Depression Inventory scored 19 and the global cognitive function was intact (Luria-Nebraska Neurological Battery screening test score: 4).

In addition to medication, she received psychotherapy following graded exposure to traumatic memories. Family intervention was arranged for collecting collateral information and family therapy. She was discharged 4 weeks later and returned home. In the following 1 year, she acted well as a wife with no more amnesic episode.

Cases of bipolar disorder comorbid DA have rarely been reported. Dissociative disorders, including DA, are generally considered psychogenic responses (Brand et al., 2012). By contrast, bipolar disorder has been studied extensively for its biological etiologies. However, with the functional brain imaging developing, some brain abnormality has been suggested to relate to DA (Brand et al., 2009, 2012). Besides, bipolar disorder had been reported with higher incidences of autobiographical memory impairments which are also a characteristic of DA, suggesting the correlation between bipolar disorder and DA (Shimizu et al., 2009).

Our opinion is, whether the etiology of the illnesses is biological or psychological, a comprehensive approach is essential for both evaluating and treating patients. In our case, not only physical examination, we performed neurological and psychological evaluation and family intervention and the treatment included medication and psychotherapy. We suggest that the biopsychosocial model be employed for not only psychiatric but all the patients.