Psychogenic Amnesia: Excellent Recovery Is Possible

Liam Davenport

August 28, 2017

Patients with psychogenic amnesia fall into four groups that have different clinical characteristics and outcomes. Those who experience fugue states have the best prognosis, a new retrospective case analysis suggests.

In a review of more than 50 cases of psychogenic amnesia, patients in fugue states recovered relatively quickly to near-normal memory recall ― despite severe, blanket memory loss.

Surprisingly, patients with psychogenic amnesia were significantly more likely to have experienced head injuries than patients with neurologic memory loss.

Still, "the prognosis in psychogenic amnesia appears better than the previous literature suggests," Michael D. Kopelman, MD, PhD, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, United Kingdom, and colleagues write.

The results "are broadly consistent with the view that psychogenic amnesia is commonly preceded by a severe precipitating crisis," a history of clinical depression or other disorders, and a history of head injury or other neurologic conditions, the investigators report.

The research was published online August 11 in Brain.

Neuropsychological Profile

The majority of previous research on psychogenic amnesia has been based on case reports, and it has thus been difficult to make generalizations about patients' neuropsychological profiles, predisposing factors, and patterns of abnormality on functional MRI studies.

To provide a more robust description of the condition and its outcomes, the researchers examined 53 cases of psychogenic amnesia seen at St Thomas's Hospital in London between 1990 and 2008.

Patients were compared with 21 patients with neurologic memory disorders who were treated at the same hospital. The study also included 10 patients with early-stage Alzheimer's disease and 14 healthy volunteers with no history of memory problems who had been recruited from the local community.

Information from each patient's medical records was gathered, including temporal characteristics of the memory gap for the patients with psychogenic amnesia. Results of neurologic assessments were also collected to determine premorbid intellectual ability and executive function.

Participants completed the Wechsler Memory Scale, revised edition, the Doors and People Test, and/or the Recognition Memory Test to assess anterograde memory; the Autobiographical Memory Interview to examine retrograde memory; and the Beck Depression Inventory.

The researchers found that patients with psychogenic amnesia fell into four groups:

  • Those with fugue states, involving a loss of sense of personal identity and a period of wandering that lasted for up to 4 weeks.

  • Those with fugue-to-focal retrograde amnesia (FRA), in which a more prolonged amnesia follows a fugue state.

  • Those who experienced psychogenic FRA following a minor neurologic episode, including head injuries.

  • Patients with gaps in their memories.

In the two fugue groups, the mean duration of the fugue state was approximately 3.75 days. Residual memory loss ranged across the four groups from 2 hours to the patients' whole life.

Loss of Identity

As expected, loss of personal identity was seen in almost all patients with fugue states (87.5%). Loss of personal identity occurred transiently in the two FRA groups (81.3% and 62.5%, respectively). It was not seen in 20% of the patients with memory gaps. Failure to recognize family was more common in the two FRA groups than in the fugue and memory gap groups.

Compared with patients who had experienced a neurologic episode, patients with psychogenic amnesia were significantly more likely to experience failure to recognize family members (odds ratio [OR], 6.23; P = .004).

In addition, patients with psychogenic amnesia were significantly more likely than neurologic patients to have depression (OR, 8.98; P < .001), family/relationship problems (OR, 4.53; P = .004), financial/employment problems (OR, 8.45; P = .003), and head injuries (OR, 6.39; P = .012).

Patients with psychogenic amnesia were also more likely than the patients who had experienced a neurologic episode to have had childhood problems (OR, 2.83; P = .153) and to have misused alcohol or other substances (OR, 2.83; P = .153), but they were not more likely to have posttraumatic stress disorder or a history of somatization.

In terms of autobiographical memory loss, patients in the fugue group had a severe and uniform loss of memories for facts and events over time. The two FRA groups had a reversed temporal gradient for memory loss; recent memories were relatively spared.

Fugue patients had improved to near-normal scores for recall of facts and near-normal scores for recall of events after 3 to 6 months. The two FRA groups had less improvement and still demonstrated the reversed temporal gradient.

On the Right Course?

It is unlikely that a case series of this size, spanning more than 20 years, is ever to be repeated ― at least in the United Kingdom, Dr Kopelman told Medscape Medical News.

St Thomas's Hospital is located in central London. Patients were directed to its accident and emergency department (A&E) by the police when they were found in the parks or railway stations. The hospital had a general psychiatric receiving ward, where all psychiatric admissions were referred.

Through this receiving ward, the investigators "were able to get to the bottom of the problem, speak to relatives when we'd been able to contact them, start to implement any treatment, such as an antidepressant, and do various things to help to set people on the right course," said Dr Kopelman.

Noting that it takes time to work out the underlying problem, he said that he did not know what currently happens to patients when they go to the A&E," but if, for example, it emerges that they come from another city, they may be redirected to that city and seen again in A&E and then sent home."

He added that it is much harder to discuss problems and sort things out if, after being admitted to the hospital, patients are put on a medical ward. "There needs to be somewhere beyond A&E where they can be seen in a 'safe' psychiatric setting, with psychiatric nurses. You can then work out what the underlying problem is and treat accordingly."

In terms of future research into psychogenic amnesia, he believes there is a case to be made for conducting a controlled trial of treatments, especially because the way in which patients are managed has changed in recent years. However, achieving a sufficient sample size would be difficult.

Dr Kopelman said he does not advocate performing neuroimaging scans on every patient that a clinician sees, although there is a place for research imaging in psychogenic amnesia "if it's done in the right context, if you put the patient's clinical priorities first."

In their article, the investigators cite the work of Michael C. Anderson, PhD, and colleagues, who have found that inhibition of memory is associated with an increase in activation in the dorso- and ventral-lateral prefrontal cortex, with associated deactivation in medial temporal structures. Dr Kopelman believes those findings are relevant in psychogenic amnesia.

"That's not been consistently found in the imaging studies to date, and there are a number of possible reasons for that," Dr Kopelman said.

"I would emphasize again that the clinical priories of getting the person out of the situation should always come first, but provided that's done, then there is a place for imaging research," he noted. "My worry is that sometimes imaging research gets done at the expense of appropriate clinical care."

No funding was provided for the study. The authors have disclosed no relevant financial relationships.

Brain. Published online August 11, 2017. Abstract

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