Narcolepsy presenting as schizophrenia

Narcolepsy and psychosis: A systematic review

OBJECTIVE

Narcolepsy is a rare sleep disorder in which psychotic-like symptoms can present diagnostic and therapeutic challenges. We aimed to review the association between, and medical management of, narcolepsy and psychosis in children and adults.

METHODS

We reviewed the full text of 100 papers from 187 identified by a PubMed search on narcolepsy plus any of these keywords: psychosis, schizophrenia, delusion, side effects, safety, and bipolar disorder.

RESULTS

Three relevant groups are described. (i) In typical narcolepsy, psychotic-like symptoms include predominantly visual hallucinations at the sleep-wake transition (experienced as "not real") and dissociation because of intrusion of rapid eye movement (REM) sleep phenomena into wakefulness. (ii) Atypical patients ("the psychotic form of narcolepsy") experience more severe and vivid, apparently REM-related hallucinations or dream/reality confusions, which patients may rationalize in a delusion-like way. (iii) Some patients have a comorbid schizophrenia spectrum disorder with psychotic symptoms unrelated to sleep. Psychostimulants used to treat narcolepsy may trigger psychotic symptoms in all three groups. We analyzed 58 published cases from groups 2 and 3 (n = 17 and 41). Features that were reported significantly more frequently in atypical patients include visual and multimodal hallucinations, sexual and mystical delusions, and false memories. Dual diagnosis patients had more disorganized symptoms and earlier onset of narcolepsy.

CONCLUSION

Epidemiological studies tentatively suggest a possible association between narcolepsy and schizophrenia only for very early-onset cases, which could be related to the partially overlapping neurodevelopmental changes observed in these disorders. We propose a clinical algorithm for the management of cases with psychotic-like or psychotic features.

Neuropsychiatric Correlates of Narcolepsy

PURPOSE OF REVIEW

The complex nature of narcolepsy symptoms, along with the use of stimulants and anticataplectic medications, poses diagnostic difficulties in terms of underlying neuropsychiatric comorbidities. This study reviews recent evidence for the association between narcolepsy and neuropsychiatric disorders. We also critically analyze studies that have addressed the neuropsychiatric correlates of patients with narcolepsy, with a discussion of the possible pathophysiological mechanisms linking narcolepsy and neuropsychiatric disorders.

RECENT FINDINGS

Neuropsychiatric manifestations are common among patients with narcolepsy as narcolepsy and some neuropsychiatric disorders share common clinical features. This may create challenges in making the correct diagnosis, and hence result in a delay in starting appropriate treatment. Comorbid neuropsychiatric manifestations in patients with narcolepsy include depression, anxiety, psychosis, rapid eye movement (REM) sleep behavior disorder, and cognitive impairment. Although hypocretin deficiency has been proposed as a pathophysiological mechanism underlying both narcolepsy and neuropsychiatric disorders, further research is necessary to identify the exact mechanisms. Narcolepsy patients often manifest comorbid neuropsychiatric symptoms, which makes the diagnosis difficult. Therefore, it is essential to address neuropsychiatric symptoms in the clinical care of patients with narcolepsy.

Comorbidity of Narcolepsy and Psychotic Disorders: A Nationwide Population-Based Study in Taiwan

BACKGROUND

Narcolepsy is a chronic sleep disorder that is likely to have neuropsychiatric comorbidities. Psychotic disorders are characterized by delusion, hallucination, and reality impairments. This study investigates the relationship between narcolepsy and psychotic disorders.

DESIGN AND METHODS

This study involves patients who were diagnosed with narcolepsy between January 2002 and December 2011 (n = 258) and age- and gender-matched controls (n = 2580) from Taiwan's National Health Insurance database. Both the patients and the controls were monitored from January 1, 2002 to December 31, 2011 to identify any occurrence of a psychotic disorder. Drugs that have been approved for treating narcolepsy: immediate-release methylphenidate (IR-MPH), osmotic controlled-release formulations of methylphenidate (OROS-MPH), and modafinil, were analyzed. A multivariate logistic regression model was used to evaluate the potential comorbidity of narcolepsy with psychotic disorders.

RESULTS

During the study period, 8.1% of the narcoleptic patients exhibited comorbidity with a psychotic disorder, whereas only 1.5% of the control subjects (1.5%) had psychotic disorders (aOR, 4.07; 95% CI, 2.21-7.47). Of the narcolepsy patients, 41.5, 5.4, and 13.2% were treated with MPH-IR, MPH-OROS, and modafinil, accordingly. Pharmacotherapy for narcolepsy did not significantly affect the risk of exhibiting a psychotic disorder.

CONCLUSIONS

This nationwide study revealed that narcolepsy and psychotic disorders commonly co-occur. Pharmacotherapy for narcolepsy was not associated with the risk of psychotic disorders. Our findings serve as a reminder that clinicians must consider the comorbidity of narcolepsy and psychosis.

Medical specialty visits and diagnoses received by Saudi patients prior to a diagnosis of narcolepsy

PURPOSE

Narcolepsy is an uncommon neurological disorder characterized by excessive daytime sleepiness (EDS) and multiple other symptoms. Due to the under-recognition of narcolepsy symptoms, patients are often misdiagnosed. This study aimed to assess the types of specialties visited and the diagnoses received by Saudi patients prior to their narcolepsy diagnosis.

METHODS

The study included 55 consecutive patients with type-1 and type-2 narcolepsy who attended the narcolepsy clinic between August 2017 and December 2017. Narcolepsy was diagnosed according to the International Classification of Sleep Disorders-third edition criteria. We evaluated sociodemographic data, the specialties visited, and diagnoses and treatments received prior to visiting a sleep specialist.

RESULTS

The mean diagnostic delay was 9.1 ± 8.4 years (1-43 years). Multiple linear regression analysis identified early onset as the only predictor of a delayed diagnosis (β coefficient = - 0.262, p = 0.03). EDS was the main symptom that prompted patients to seek medical consultation, and only one patient had been (1.8%) referred with the diagnosis of narcolepsy. In the study group, 82% of the patients were misdiagnosed with a mental or neurological disorder or were thought to be afflicted by "envy," "evil eye," or "black magic" before receiving a correct diagnosis. No significant differences were detected between patients with narcolepsy type-1 and narcolepsy type-2.

CONCLUSIONS

Delays in diagnosing narcolepsy remain a major problem for Saudi patients with this disorder. We found that Saudi patients with narcolepsy had visited several medical specialists and faith healers and were misdiagnosed prior to visiting a sleep specialist.

Narcolepsy and emotional experience: a review of the literature

Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. This disease affects significantly the overall patient functioning, interfering with social, work, and affective life. Some symptoms of narcolepsy depend on emotional stimuli; for instance, cataplectic attacks can be triggered by emotional inputs such as laughing, joking, a pleasant surprise, and also anger. Neurophysiological and neurochemical findings suggest the involvement of emotional brain circuits in the physiopathology of cataplexy, which seems to depending on the dysfunctional interplay between the hypothalamus and the amygdala associated with an alteration of hypocretin levels. Furthermore, behavioral studies suggest an impairment of emotions processing in narcolepsy-cataplexy (NC), like a probable coping strategy to avoid or reduce the frequency of cataplexy attacks. Consistently, NC patients seem to use coping strategies even during their sleep, avoiding unpleasant mental sleep activity through lucid dreaming. Interestingly, NC patients, even during sleep, have a different emotional experience than healthy subjects, with more vivid, bizarre, and frightening dreams. Notwithstanding this evidence, the relationship between emotion and narcolepsy is poorly investigated. This review aims to provide a synthesis of behavioral, neurophysiological, and neurochemical evidence to discuss the complex relationship between NC and emotional experience and to direct future research.

Psychosocial Profile and Quality of Life in Children With Type 1 Narcolepsy: A Case-Control Study

STUDY OBJECTIVES

To investigate behavioral aspects and quality of life in children and adolescents with type 1 narcolepsy (NT1).

METHODS

We performed a case-control study comparing 29 patients with NT1 versus sex- and age-matched patients with idiopathic epilepsy (n = 39) and healthy controls (n = 39). Behavior and quality of life were evaluated by self-administered questionnaires (Child Behavior Checklist, Pediatric Quality of Life Inventory). Patient groups were contrasted and scale results were correlated with clinical and polysomnographic parameters, and cerebrospinal fluid hypocretin-1 levels.

RESULTS

Young patients with NT1 showed increased internalizing problems associated with aggressive behavior. Emotional profile in patients with NT1 positively correlated with age at onset, diagnostic delay, and subjective sleepiness, whereas treatment and disease duration were associated with fewer behavioral problems (attention problems, aggressive behavior, and attention deficit/hyperactivity disorder). Psychosocial health domains of pediatric NT1 were worse than in healthy controls, whereas the physical health domains were comparable.

CONCLUSIONS

Young NT1 patients show a discrete pattern of altered behavioral, thought, and mood profile in comparison with healthy controls and with idiopathic epilepsy patients thus suggesting a direct link with sleepiness. Further studies investigating behavior in patients with idiopathic hypersomnia or type 2 narcolepsy are needed to disentangle the role of REM sleep dysfunction and hypocretin deficiency in psychiatric disorders. Symptoms of withdrawal, depression, somatic complaints, thought problems, and aggressiveness were common, NT1 children perceived lower school competencies than healthy children, and their parents also reported worse psychosocial health. Our data suggest that early effective treatment and disease self-awareness should be promoted in NT1 children for their positive effect on behavior and psychosocial health.

Exploring the presence of narcolepsy in patients with schizophrenia

BACKGROUND

There are several case reports of patients with narcolepsy and schizophrenia, but a systematic examination of the association of both disorders has not been done. The aim of this work is to assess the frequency of narcolepsy with cataplexy in a large consecutive series of adult patients with schizophrenia and schizoaffective disorder.

METHODS

We screened 366 consecutive patients with schizophrenia or schizoaffective disorder with a sleep questionnaire and the Epworth Sleepines scale (ESS) exploring narcoleptiform symptoms. Those who screened positive were assessed by a sleep specialist, and offered an HLA determination. CSF hypocretin-1 determination was proposed to those who were HLA DQB1*06:02 positive.

RESULTS

On the screening questionnaire, 17 patients had an ESS score ≥11 without cataplexy, 15 had cataplexy-like symptoms with an ESS score < 11, and four had an ESS score ≥11 plus cataplexy-like symptoms. Of those, 24 patients were evaluated by a sleep specialist. Five of these 24 were HLA DQB1*06:02 positive, and three of these five subjects underwent lumbar puncture showing normal hypocretin-1 levels.

CONCLUSIONS

Our results suggest that narcolepsy with cataplexy is not an unrecognized disease in adult patients with schizophrenia or schizoaffective disorder.

Schizophrenia-like symptoms in narcolepsy type 1: shared and distinctive clinical characteristics

BACKGROUND/AIMS

The occurrence of psychotic symptoms in narcolepsy type 1 (NT1) has been reported as responsible for delayed diagnosis due to the misdiagnosis of schizophrenia. This study aimed to identify shared and distinctive clinical characteristics between NT1 and schizophrenia, with the focus on psychotic symptoms.

METHODS

A total of 28 NT1 and 21 schizophrenia patients were included. Hallucination characteristics and PANSS (Positive and Negative Syndrome Scale), HRSD (Hamilton Rating Scale for Depression), DES (Dissociative Experiences Scale), and STAI (State-Trait Anxiety Inventory) scores were collected. Symptom overlap was investigated by χ(2), Fisher's or t tests and multiple logistic regression models.

RESULTS

Hallucinations and illusions frequently occurred in both diseases. Unimodal hallucinations were more common in schizophrenia (p = 6.30e-07) and multimodal hallucinations in NT1, but no clear difference was identified in their sensory modality. Hypnagogic/hypnopompic hallucinations were typical of NT1 (p = 5.22e-07), and 25% of NT1 patients exhibited some degree of insight deficit. Hypnagogic/hypnopompic hallucinations, unimodal hallucinations and PANSS score were the most distinctive clinical characteristics. Clinical overlap was found in the dissociative and anxiety domains, while higher depressive scores were observed in schizophrenia.

CONCLUSION

The overlap between NT1 and schizophrenia should be further investigated under a clinical and pathogenetic point of view to improve diagnostic and therapeutic approaches.

Narcolepsy: a review

Narcolepsy is a lifelong sleep disorder characterized by a classic tetrad of excessive daytime sleepiness with irresistible sleep attacks, cataplexy (sudden bilateral loss of muscle tone), hypnagogic hallucination, and sleep paralysis. There are two distinct groups of patients, ie, those having narcolepsy with cataplexy and those having narcolepsy without cataplexy. Narcolepsy affects 0.05% of the population. It has a negative effect on the quality of life of its sufferers and can restrict them from certain careers and activities. There have been advances in the understanding of the pathogenesis of narcolepsy. It is thought that narcolepsy with cataplexy is secondary to loss of hypothalamic hypocretin neurons in those genetically predisposed to the disorder by possession of human leukocyte antigen DQB1*0602. The diagnostic criteria for narcolepsy are based on symptoms, laboratory sleep tests, and serum levels of hypocretin. There is no cure for narcolepsy, and the present mainstay of treatment is pharmacological treatment along with lifestyle changes. Some novel treatments are also being developed and tried. This article critically appraises the evidence for diagnosis and treatment of narcolepsy.

Treatment dilemmas in a young man presenting with narcolepsy and psychotic symptoms

Psychotic features can be present in both narcolepsy and psychosis, which can result in challenges in diagnosis and management. The prevalence of both conditions is low and the reports in young people are scarce. Our report illustrates the relevance of a thorough differential diagnosis as well as the need to explore treatment avenues based on the evidence available for both narcolepsy and psychosis symptoms to try and maximise the therapeutic impact.

The orexins/hypocretins and schizophrenia

Advances in molecular biology have led to new peptides and proteins being discovered on a regular basis, including the isolation of a number of neurotransmitter candidates. Rarely, however, do these immediately capture the attention of the scientific community. The isolation and characterization of the orexin/hypocretin peptides a decade ago resulted in a slew of studies that have helped clarified their diverse functions, including prominent roles in arousal and appetitive behavior. A number of recent studies have detailed the role of the orexins/hypocretins in attention and cognition and uncovered an involvement in schizophrenia and the mechanisms of action of antipsychotic drugs (APDs). This issue of Schizophrenia Bulletin presents several articles that review our current understanding and point to future directions for the study of the orexins/hypocretins in schizophrenia and APD actions.

Is Schizophrenia Associated with Narcolepsy?

OBJECTIVE

To determine the nature of the relationship between schizophrenia-like psychosis and narcolepsy.

BACKGROUND

A relationship between schizophrenia and narcolepsy has long been postulated due to the association of schizophrenia-like psychosis with narcolepsy and its treatment.

METHOD

We report two patients who presented with schizophrenia-like psychosis of narcolepsy and review the literature regarding possible shared neurobiology between the two disorders that might explain their co-occurrence.

RESULTS

There appears to be little in the way of common pathology between these two conditions when symptoms, human leukocyte antigen associations, rapid eye movement sleep architecture, D2-dopamine receptor changes, and hypocretinergic function are examined.

CONCLUSIONS

The available literature suggests that schizophrenia-like psychosis in narcolepsy is most commonly medication related or a chance co-occurrence, with limited evidence for a separate psychosis of narcolepsy.

Schizophrenia and narcolepsy: a review with a case report

Several reports emphasize the importance of differentiating between psychosis in schizophrenia and the psychotic form of narcolepsy. The failure to identify narcolepsy leads to the labeling of patients as refractory to standard treatments for schizophrenia and retards consideration of intervention for narcolepsy in which psychosis can improve with psychostimulant treatment. Psychosis in patients with narcolepsy can occur in three ways: (i) as the psychotic form of narcolepsy with hypnagogic and hypnopompic hallucinations; (ii) as a result of psychostimulant use in a patient with narcolepsy; and (iii) as the concurrent psychosis of schizophrenia in a patient with narcolepsy. The present case report describes a difficult-to-treat patient who likely had concurrent schizophrenia and narcolepsy. It then summarizes the literature related to the treatment of the three types of patients with psychosis associated with narcolepsy.