Phenomenology and psychiatric correlates of pseudocataplexy.

Study objectives: Pseudocataplexy is a rare functional neurological disorder that mimics cataplexy, pathognomonic for narcolepsy type 1 (NT1). We describe the psychiatric comorbidity and personality traits of patients with pseudocataplexy versus NT1 cases.

Methods: The case-control observational study enrolled consecutive patients with pseudocataplexy and a control group of age-matched consecutive NT1 patients. The diagnostic work-up included a structured interview, 48-hour polysomnography, multiple sleep latency test, cataplexy provoking test, and hypocretin-1 measurement in cerebrospinal fluid. All participants were administered Beck Depression Inventory, State-Trait Anxiety Inventory, Patient Health Questionnaire-15 (PHQ-15), Personality Inventory for DSM-5 brief form, and quality-of-life (QoL) measurement by 36-item Short Form health survey (SF-36).

Results: Fifteen patients with pseudocataplexy and 30 with NT1 were included. Despite the suspicion of possible cataplexy, none of the pseudocataplexy participants fulfilled international diagnostic criteria for NT1. Pseudocataplexy patients presented higher rates of moderate state anxiety (40% vs. 10%, p = 0.018), medium level of somatic symptoms, defined by PHQ-15 score > 10 (66.7% vs. 16.7%, p = 0.003), and a trend towards moderate-to-severe depressive symptoms (33.3% vs. 10%, p = 0.054) compared to NT1. No significant differences in personality traits emerged. Pseudocataplexy patients had worse QoL profiles in almost all SF-36 domains including physical (mean ± SD: 37.7 ± 9.88 vs. 51.13 ± 7.81, p < 0.001) and mental (mean ± SD: 33.36 ± 12.69 vs.42.76 ± 11.34, p = 0.02) summary scores.

Conclusions: Patients with pseudocataplexy present more severe psychiatric symptoms and a lower QoL profile in comparison with patients with NT1. The severe somatoform and affection impairment in pseudocataplexy may explain the poorer QoL and should require a tailored therapeutic approach.