Schizophrenia and narcolepsy: a review with a case report

A Dynamic Foundation: Aberrations of Sleep Architecture and Its Association With Clinical and Sub-clinical Psychopathology

This investigation centered on the hypnagogic and hypnopompic wake-sleep/sleep-wake transition states and the associated exploration of hypnagogic and hypnopompic experiences (HHEs), and sleep paralysis (SP) on psychiatric exacerbation and paradoxical masking. The study aims to discern causality by examining how these sleep-related experiences may contribute to the emergence or exacerbation of psychiatric and neurodegenerative conditions, particularly, pertaining to the clinical or sub-clinical demographic of Schizotypal Personality Disorder (STPD), Mood Disorders, Schizophrenia, Post-Traumatic Stress Disorder (PTSD), Generalized Anxiety Disorder (GAD), Narcolepsy, Panic Disorder, specific phobias, or heightened psychotic sensitivity. Methodologically, this study employed a comprehensive literature review, drawing from a range of studies across sleep medicine, psychiatry, and psychology, utilizing PubMed-indexed peer-reviewed scientific literature, sourcing from academic institutions, Google Scholar, and open-access publications. This interdisciplinary approach allowed for a nuanced and systematic understanding of the potential links between specific sleep-wake/wake-sleep aberrations and their masking or exacerbation of clinical/sub-clinical psychiatric symptomatology in this particular demographic. Insights gained from the outcome of this study hold promise for advancing understanding of the interrelationship between sleep neurobiology and psychiatric disorders. Additionally, the findings may inform targeted therapeutic interventions tailored to mitigate the impact of sleep-wake disruptions on vulnerable populations. The overarching objective is to bridge current gaps in knowledge, cultivating a more profound understanding with direct implications for both clinical practice and ongoing research endeavors. The study outcomes provide an intriguing understanding of the complex relationship between sleep neurobiology and psychiatric disorders, paving the way for targeted therapeutic interventions to alleviate the effects of sleep-wake disruptions, and addressing critical gaps in knowledge with direct implications for clinical practice and ongoing research.

Narcolepsy and psychiatric disorders: A bidirectional Mendelian randomization study

Since the introduction of the concept of narcolepsy, there has been a proliferation of discussions about its association with psychiatry. To elucidate the causal role of narcolepsy in the three psychiatric disorders [i.e., schizophrenia (SCZ), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD)], we applied a bidirectional Mendelian randomization study using two stages (discovery stage and validation stage) and data from three different genome-wide association studies of narcolepsy. The estimates from different stages were combined using fixed-effects meta-analysis. Our findings suggest that narcolepsy is associated with an increased risk of SCZ. Conversely, MDD may be causally related to narcolepsy. A causal relationship between narcolepsy and ADHD was excluded.

Psychosis Caused by a Somatic Condition: How to Make the Diagnosis? A Systematic Literature Review

BACKGROUND

First episode of psychosis (FEP) is a clinical condition that usually occurs during adolescence or early adulthood and is often a sign of a future psychiatric disease. However, these symptoms are not specific, and psychosis can be caused by a physical disease in at least 5% of cases. Timely detection of these diseases, the first signs of which may appear in childhood, is of particular importance, as a curable treatment exists in most cases. However, there is no consensus in academic societies to offer recommendations for a comprehensive medical assessment to eliminate somatic causes.

METHODS

We conducted a systematic literature search using a two-fold research strategy to: (1) identify physical diseases that can be differentially diagnosed for psychosis; and (2) determine the paraclinical exams allowing us to exclude these pathologies.

RESULTS

We identified 85 articles describing the autoimmune, metabolic, neurologic, infectious, and genetic differential diagnoses of psychosis. Clinical presentations are described, and a complete list of laboratory and imaging features required to identify and confirm these diseases is provided.

CONCLUSION

This systematic review shows that most differential diagnoses of psychosis should be considered in the case of a FEP and could be identified by providing a systematic checkup with a laboratory test that includes ammonemia, antinuclear and anti-NMDA antibodies, and HIV testing; brain magnetic resonance imaging and lumbar puncture should be considered according to the clinical presentation. Genetic research could be of interest to patients presenting with physical or developmental symptoms associated with psychiatric manifestations.

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.

Treatment of Isolated Cataplexy With Low-dose Aripiprazole in an Adolescent Patient

BACKGROUND

Cataplexy is a clinical entity that is characterized by transient muscle tone loss that mostly occurring as a part of narcolepsy. On the other hand, isolated cataplexy (IC) (hereditary cataplexy) is defined as loss of muscle tone that is not accompanied by narcolepsy. Emotional reactions may trigger IC episodes. Additionally, human leukocyte antigen (HLA) DQB1 alleles were shown to be related to IC. Various antidepressants are useful in the treatment of IC; however, there is limited knowledge on the use of antipsychotics in the treatment of IC.

CASE REPORT

A 16-year-old adolescent girl was consulted child and adolescent psychiatry outpatient clinic with complaint of sudden episodes of loss of muscle tone. Her HLA typing showed HLA DQB1*03 haplotype. She was diagnosed with IC and was prescribed aripiprazole 2.5 mg/d and her IC symptoms disappeared and never recurred over 6 months of follow-up.

CONCLUSIONS

In this case report, we present an adolescent girl with IC that is successfully treated with aripiprazole, an antipsychotic. This case report suggests that aripiprazole may be safely used in some adolescents who diagnosed with IC.

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.

Prevalence and correlates of sleep disorder symptoms in psychiatric disorders

Difficulty falling asleep or maintaining sleep, poor sleep quality, nightmares, and excessive daytime sleepiness are some of the key clinical symptoms of sleep disturbances observed among individuals with psychiatric illnesses. This study aimed to determine the prevalence of symptoms of sleep disorders including parasomnia, narcolepsy, obstructive sleep apnea, circadian rhythm disorder and restless leg syndrome/periodic limb movement (RLS/PLMS) and its correlates in patients with psychiatric diagnoses. Patients aged 21-65 years (n = 400) attending the outpatient clinics with a primary diagnosis of either schizophrenia, mood or anxiety disorder based on ICD-9 criteria were included in this cross-sectional study. Sociodemographic information was collected and screening questions pertaining to specific symptoms of sleep disorders were administered by a study team member. The overall prevalence of symptoms of sleep disorders in the psychiatric outpatient sample was 40.75% (163/400). The prevalence for symptoms of narcolepsy, sleep breathing disorder, PLMS/RLS, circadian rhythm disorder and parasomnia were 12.5%, 14.5%, 14.8%, 4.5%, and 13.8% respectively. These symptoms were associated with age, low physical activity, and anxiety disorder. Results highlight the high prevalence of symptoms of sleep disorders in psychiatric patients. Present study findings should be confirmed using diagnostic interviews and objective measures.

What Is the Link Between Hallucinations, Dreams, and Hypnagogic-Hypnopompic Experiences?

By definition, hallucinations occur only in the full waking state. Yet similarities to sleep-related experiences such as hypnagogic and hypnopompic hallucinations, dreams and parasomnias, have been noted since antiquity. These observations have prompted researchers to suggest a common aetiology for these phenomena based on the neurobiology of rapid eye movement (REM) sleep. With our recent understanding of hallucinations in different population groups and at the neurobiological, cognitive and interpersonal levels, it is now possible to draw comparisons between the 2 sets of experiences as never before. In the current article, we make detailed comparisons between sleep-related experiences and hallucinations in Parkinson's disease, schizophrenia and eye disease, at the levels of phenomenology (content, sensory modalities involved, perceptual attributes) and of brain function (brain activations, resting-state networks, neurotransmitter action). Findings show that sleep-related experiences share considerable overlap with hallucinations at the level of subjective descriptions and underlying brain mechanisms. Key differences remain however: (1) Sleep-related perceptions are immersive and largely cut off from reality, whereas hallucinations are discrete and overlaid on veridical perceptions; and (2) Sleep-related perceptions involve only a subset of neural networks implicated in hallucinations, reflecting perceptual signals processed in a functionally and cognitively closed-loop circuit. In summary, both phenomena are non-veridical perceptions that share some phenomenological and neural similarities, but insufficient evidence exists to fully support the notion that the majority of hallucinations depend on REM processes or REM intrusions into waking consciousness.

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.

Isolated sleep paralysis and hypnic hallucinations in schizophrenia

BACKGROUND

Usually remembered in the context of Narcolepsy-Cataplexy syndrome, isolated sleep paralysis (SP) and hypnic hallucination are widely prevalent and because of the overlap of symptoms with schizophrenia, their identification is important but unrecognized.

AIMS

To determine the presence of SP and hypnic hallucinations (HH) in people with schizophrenia and schizoaffective disorder.

STUDY DESIGN

Cross-sectional survey.

METHODS

Participants were patients receiving follow-up care for schizophrenia from Assertive Community Treatment Team. A screening questionnaire was administered during their routine follow-up visits.

RESULTS

Of 71 respondents (49 males, 22 females) only 11 (10 males and 1 female), that is, 15% reported SP, and 12 (7 males and 5 females), that is, 16.9% reported HH, a considerably low prevalence.

CONCLUSION

It is difficult to study the presence of SP and HH in patients with active or residual symptoms of schizophrenia, and more refined studies and appropriate questionnaires are required. The possibility of SP and HH confounding or being misdiagnosed as psychotic symptoms needs to be borne in mind.

Dual cases of type 1 narcolepsy with schizophrenia and other psychotic disorders

OBJECTIVE

Cases of narcolepsy in association with psychotic features have been reported but never fully characterized. These patients present diagnostic and treatment challenges and may shed new light on immune associations in schizophrenia.

METHOD

Our case series was gathered at two narcolepsy specialty centers over a 9-year period. A questionnaire was created to improve diagnosis of schizophrenia or another psychotic disorder in patients with narcolepsy. Pathophysiological investigations included full HLA Class I and II typing, testing for known systemic and intracellular/synaptic neuronal antibodies, recently described neuronal surface antibodies, and immunocytochemistry on brain sections to detect new antigens.

RESULTS

Ten cases were identified, one with schizoaffective disorder, one with delusional disorder, two with schizophreniform disorder, and 6 with schizophrenia. In all cases, narcolepsy manifested first in childhood or adolescence, followed by psychotic symptoms after a variable interval. These patients had auditory hallucinations, which was the most differentiating clinical feature in comparison to narcolepsy patients without psychosis. Narcolepsy therapy may have played a role in triggering psychotic symptoms but these did not reverse with changes in narcolepsy medications. Response to antipsychotic treatment was variable. Pathophysiological studies did not reveal any known autoantibodies or unusual brain immunostaining pattern. No strong HLA association outside of HLA DQB1*06:02 was found, although increased DRB3*03 and DPA1*02:01 was notable.

CONCLUSION

Narcolepsy can occur in association with schizophrenia, with significant diagnostic and therapeutic challenges. Dual cases maybe under diagnosed, as onset is unusually early, often in childhood. Narcolepsy and psychosis may share an autoimmune pathology; thus, further investigations in larger samples are warranted.

Psychiatric disorders and sleep issues

Sleep issues are common in people with psychiatric disorders, and the interaction is complex. Sleep disorders, particularly insomnia, can precede and predispose to psychiatric disorders, can be comorbid with and exacerbate psychiatric disorders, and can occur as part of psychiatric disorders. Sleep disorders can mimic psychiatric disorders or result from medication given for psychiatric disorders. Impairment of sleep and of mental health may be different manifestations of the same underlying neurobiological processes. For the primary care physician, key tools include recognition of potential sleep effects of psychiatric medications and familiarity with treatment approaches for insomnia in depression and anxiety.

Psychosis in patients with narcolepsy as an adverse effect of sodium oxybate

Aim: Hypnagogic and hypnopompic hallucinations are characteristic symptoms of narcolepsy, as are excessive daytime sleepiness, cataplexy, and sleep paralysis. Narcolepsy patients may also experience daytime hallucinations unrelated to sleep–wake transitions. The effect of medication on hallucinations is of interest since treatment of narcolepsy may provoke psychotic symptoms. We aim to analyze the relation between sodium oxybate (SXB) treatment and psychotic symptoms in narcolepsy patients. Furthermore, we analyze the characteristics of hallucinations to determine their nature as mainly psychotic or hypnagogic and raise a discussion about whether SXB causes psychosis or if psychosis occurs as an endogenous complication in narcolepsy.

Method: We present altogether four patients with narcolepsy who experienced psychotic symptoms during treatment with SXB. In addition, we searched the literature for descriptions of hallucinations in narcolepsy and similarities and differences with psychotic symptoms in schizophrenia.

Results: Three out of four patients had hallucinations typical for psychosis and one had symptoms that resembled aggravated hypnagogic hallucinations. Two patients also had delusional symptoms primarily associated with mental disorders. Tapering down SXB was tried and helped in two out of four cases. Adding antipsychotic treatment (risperidone) alleviated psychotic symptoms in two cases.

Conclusion: Psychotic symptoms in narcolepsy may appear during SXB treatment. Hallucinations resemble those seen in schizophrenia; however, the insight that symptoms are delusional is usually preserved. In case of SXB-induced psychotic symptoms or hallucinations, reducing SXB dose or adding antipsychotic medication can be tried.

The hypocretin system and psychiatric disorders

The hypocretin system is constituted by a small group of hypothalamic neurons with widespread connections within the entire central nervous system producing two neuropeptides involved in several key physiological functions such as the regulation of sleep and wakefulness, motor control, autonomic functions, metabolism, feeding behavior, and reward. Narcolepsy with cataplexy is a neurological disorder regarded as a disease model for the selective hypocretin system damage, and also shares several psychopatological traits and comorbidities with psychiatric disorders. We reviewed the available literature on the involvement of the hypocretin system in psychiatric nosography. Different evidences such as cerebrospinal hypocretin-1 levels, genetic polymorphisms of the neuropeptides or their receptors, response to treatments, clinical, experimental and functional data directly or indirectly linked the hypocretin system to schizophrenia, mood, anxiety and eating disorders, as well as to addiction. Future genetic and pharmacological studies will disentangle the hypocretin system role in the field of psychiatry.

Narcolepsy-cataplexy and schizophrenia in adolescents

BACKGROUND

Despite advances in the understanding of narcolepsy, little information the on association between narcolepsy and psychosis is available, except for amphetamine-related psychotic reactions. Our case-control study aimed to compare clinical differences and analyze risk factors in children who developed narcolepsy with cataplexy (N-C), schizophrenia, and N-C followed by schizophrenia.

METHODS

Three age- and gender-matched groups of children with N-C schizophrenia (study group), N-C (control group 1), and schizophrenia only (control group 2) were investigated. Subjects filled out sleep questionnaires, sleep diaries, and quality of life scales, followed by polysomnography (PSG), multiple sleep latency tests (MSLT), routine blood tests, HLA typing, genetic analysis of genes of interest, and psychiatric evaluation. The risk factors for schizophrenia also were analyzed.

RESULTS

The study group was significantly overweight when measuring body mass index (BMI) (P=.016), at narcolepsy onset compared to control group 1, and the study group developed schizophrenia after a mean of 2.55±1.8 years. Compared to control group 2, psychotic symptoms were significantly more severe in the study group, with a higher frequency of depressive symptoms and acute ward hospitalization in 8 out of 10 of the subjects. They also had poorer long-term response to treatment, despite multiple treatment trials targeting their florid psychotic symptoms. All subjects with narcolepsy were HLA DQ B1(∗)0602 positive. The study group had a significantly higher frequency of DQ B1(∗)-03:01/06:02 (70%) than the two other groups, without any significant difference in HLA-DR typing, tumor necrosis factor α (TNF-α) levels, hypocretin (orexin) receptor 1 gene, HCRTR1, and the hypocretin (orexin) receptor 2 gene, HCRTR2, or blood infectious titers.

CONCLUSION

BMI and weight at onset of narcolepsy as well as a higher frequency of DQ B1(∗)-03:01/06:02 antigens were the only significant differences in the N-C children with secondary schizophrenia; such an association is a therapeutic challenge with long-term persistence of severe psychotic symptoms.

Injurious REM sleep behaviour disorder in narcolepsy with cataplexy contributing to criminal proceedings and divorce

We present a case of violent sleep-related behaviour in a patient with narcolepsy with cataplexy (NC) and REM sleep behaviour disorder (RBD), causing injuries to his wife that resulted in charge of assault, followed by a divorce case. This observation pinpoints that RBD in NC can arise early in a patient's life and that it can be violent, that pharmacological treatment for RBD has to be considered in this case, that lack (or delay) of RBD diagnoses may further exacerbate the psychosocial burden of NC, and that a general awareness of the nature of sleep related violence may avoid unfortunate legal and personal consequences for patients, their partners and families.

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.

Methylphenidate-induced psychosis in adult attention-deficit/hyperactivity disorder: report of 3 new cases and review of the literature

OBJECTIVE

We present 3 new cases of psychotic symptoms in patients with adult attention-deficit/hyperactivity disorder while regularly treated with a stimulant therapy with methylphenidate.

METHODS

Existing literature about this theme is reviewed, and potential mechanisms are discussed.

RESULTS AND CONCLUSIONS

Medication with methylphenidate should be avoided in patients with vulnerability to schizophrenia and in drug addiction, but reported cases without these risk factors demonstrate that a careful and regular psychiatric monitoring is essential in all patients treated with methylphenidate.

Sleep in psychiatric disorders: where are we now?

Although the precise function of sleep is unknown, decades of research strongly implicate that sleep has a vital role in central nervous system (CNS) restoration, memory consolidation, and affect regulation. Slow-wave sleep (SWS) and rapid eye movement (REM) sleep have been of significant interest to psychiatrists; SWS because of its putative role in CNS energy recuperation and cognitive function, and REM sleep because of its suggested involvement in memory, mood regulation, and possible emotional adaptation. With the advent of the polysomnogram, researchers are now beginning to understand some of the consequences of disrupted sleep and sleep deprivation in psychiatric disorders. The same neurochemistry that controls the sleep-wake cycle has also been implicated in the pathophysiology of numerous psychiatric disorders. Thus it is no surprise that several psychiatric disorders have prominent sleep symptoms. This review will summarize normal sleep architecture, and then examine sleep abnormalities and comorbid sleep disorders seen in schizophrenia, as well as anxiety, cognitive, and substance abuse disorders.

Psychotic symptoms in narcolepsy: phenomenology and a comparison with schizophrenia

OBJECTIVE

Patients with narcolepsy often experience pervasive hypnagogic hallucinations, sometimes even leading to confusion with schizophrenia. We aimed to provide a detailed qualitative description of hypnagogic hallucinations and other "psychotic" symptoms in patients with narcolepsy and contrast these with schizophrenia patients and healthy controls. We also compared the prevalence of formal psychotic disorders between narcolepsy patients and controls.

METHODS

We used SCAN 2.1 interviews to compare psychotic symptoms between 60 patients with narcolepsy, 102 with schizophrenia and 120 matched population controls. In addition, qualitative data was collected to enable a detailed description of hypnagogic hallucinations in narcolepsy.

RESULTS

There were clear differences in the pattern of hallucinatory experiences in narcolepsy vs. schizophrenia patients. Narcoleptics reported multisensory "holistic" hallucinations rather than the predominantly verbal-auditory sensory mode of schizophrenia patients. Psychotic symptoms such as delusions were not more frequent in narcolepsy compared to population controls. In addition, the prevalence of formal psychotic disorders was not increased in patients with narcolepsy. Almost half of narcoleptics reported moderate interference with functioning due to hypnagogic hallucinations, mostly due to related anxiety.

CONCLUSIONS

Hypnagogic hallucinations in narcolepsy can be differentiated on a phenomenological basis from hallucinations in schizophrenia which is useful in differential diagnostic dilemmas.

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.