We present the case of a 23-year-old White British man who presented with persistent déjà vu in 2010. He reported experiencing these symptoms since early 2007 shortly after starting university. He had a history of feeling anxious, particularly in relation to contamination, which led him to wash his hands very frequently and to shower two to three times per day, and his anxiety worsened around the time he began university. Anxiety and low mood led him to take a break from university, and he then began experiencing déjà vu. His recollection of these early episodes was that they would last for minutes, but could also be extremely prolonged. For example, while on holiday in a destination that he had previously visited he reported feeling as though he had become ‘trapped in a time loop’. He reported finding these experiences very frightening.

He returned to university in 2007 and he described the déjà vu episodes as becoming more intense. He took lysergic acid diethylamide (LSD) once, and from then on the déjà vu was fairly continuous. In 2008 he was referred to specialists for neurological examination. Routine electroencephalogram (EEG) and magnetic resonance imaging were performed at a centre with experience in the diagnosis of epilepsy and were both normal. He was given a psychiatric diagnosis of depersonalisation and treated with a range of medications. His Dissociative Events Scale score (35.36) was abnormal (cut off =30) at the time of conducting the recognition memory task (October 2009).

He was assessed by AZ in 2010, at which point his persistent déjà vu caused him to avoid watching television and listening to the radio, as well as reading papers and magazines, as he felt he had already encountered the content before. His neurological examination was normal. At the time of assessment he reported a chronically low mood and felt anxious much of the time, although his compulsive behaviours were not a problem. There was a family history of obsessive compulsive disorder (OCD) on his paternal and possibly maternal side. Summary scores from his neuropsychological evaluation are presented in Table 1. His performance on the National Adult Reading Test was not dissimilar to that of controls, and his performance on the Wechsler Adult Intelligence Scale estimated his intelligence quotient as 112.

Table 1 Patient and control group characteristics Full size table

In October 2009 we assessed his performance on a recognition memory task previously used with patients who report similar persistent déjà vu experiences/recollective confabulation (see [6], Experiment 3 for methodology). A comparison group of 11 male undergraduates conducted the same memory task (see Table 1 for sample characteristics). The control group were within the normal range for depression and stress as measured by the Depression Anxiety and Stress Scales, DASS-21, but were defined as having mild anxiety: note, lower cut-off is 7. They were also asked whether they had heard of déjà vu, frequency of déjà vu in the last month, and whether it impacted on their daily life. Eight controls had heard of déjà vu, one had not and two did not answer. Of the eight who had heard of déjà vu, only three had experienced it in the past month: two, three and 12 times. Of interest, the participant who reported approximately 12 déjà vu experiences within the past month scored highly on all subscales of the DASS, and his anxiety score was rated ‘extremely severe’, although he did not report that déjà vu impacted on his daily life. In short, the procedure for the memory task is as follows: participants study 30 words for an immediate test. They are then read a list of 60 words (30 studied words and 30 foils) and report whether each word is old or new. If classified as old, they report whether they remember it (can justify how they encountered it), find it familiar (they feel they have encountered it but cannot justify) or are guessing. We have previously demonstrated in dementia that people with persistent déjà vu-like experiences make very high levels of false positives (FPs), identifying new words as previously seen [6]. We have linked this deficit to a subtype of déjà vu, a disorder in the subjective experience of memory, as identified in the reports of ‘remembering’ and familiarity, which we termed déjà vecu. Déjà vecu is a particularly strong sensation of ‘re-living’ the present moment; it was this type of experience of which our case complained: rather than simply the unsettling feelings of familiarity which are normally associated with déjà vu, he complained that it felt like he was actually retrieving previous experiences from memory, not just finding them familiar.

Performance on the task is summarised in Table 1. Contrary to our expectations, our case made no FPs. Recognition memory was measured across all items and for all subjective states using a discrimination index, where FPs are subtracted from hits. His performance suggests he does not have a memory deficit, but his conservative performance (relatively low number of remember hits compared to controls and no guesses) suggests that he may be less confident in his memory ability than controls.