Prader-Willi syndrome and psychotic symptoms: report of a further case

Psychotic illness in people with Prader-Willi syndrome: a systematic review of clinical presentation, course and phenomenology

BACKGROUND

Prader-Willi syndrome (PWS) is a rare and complex neurodevelopmental disorder resulting from absent paternal expression of maternally imprinted genes at chromosomal locus 15q11-13. This absence of expression occurs as a consequence of a deletion on the chromosome 15 of paternal origin (ca. 70%), a chromosome 15 maternal uniparental disomy (mUPD; ca. 25%), or an imprinting centre defect (IC; ca. 1-3%). At birth, individuals with PWS are severely hypotonic and fail to thrive. Hyperphagia and characteristic physical and neuropsychiatric phenotypes become apparent during childhood. The risk for the development of a co-morbid psychotic illness increases during the teenage years, specifically in those with PWS due to the presence of an mUPD. The primary aim of this literature review is to inform clinical practice. To achieve this, we have undertaken a systematic analysis of the clinical research literature on prevalence, presentation, course, characteristics, diagnosis and treatment of psychotic illness in people with PWS. The secondary aim is to identify clinical aspects of psychotic illness in PWS in need of further investigation.

METHODS AND FINDINGS

A systematic literature review on psychosis in PWS was conducted on the databases Web of Knowledge, PubMed and Scopus, using the terms "((Prader-Willi syndrome) OR (Prader Willi Syndrome)) AND ((psychosis) OR (psychotic illness))". All articles written in English and reporting original human research were reviewed. In all but three of the 16 cohort studies in which the genetic types were known, the authors reported higher rates of psychosis in people with PWS resulting from an mUPD, compared to those with the deletion subtype of PWS. When psychosis was present the presentation was psychosis similar regardless of genetic type and was usually characterised by an acute onset of hallucinations and delusions accompanied by confusion, anxiety and motor symptoms.

CONCLUSIONS

The onset of confusion, an affective cyclical pattern with the presence of abnormal mental beliefs and experiences, usually of rapid onset is suggestive of the development of psychotic illness. Phenomenologically, this psychosis in people with PWS is atypical in comparison to schizophrenia and bipolar disorder in the general population. The relationship to psychosis in the general population and the optimum treatments remain uncertain.

Psychotic disorders in Prader-Willi syndrome

The Prader-Willi syndrome (PWS) is a genetically determined developmental disorder caused by abnormalities of the proximal region of chromosome 15q11-13. In a previous study, we reported that psychotic episodes, occurring in 16% of persons with PWS, had an onset in adolescence, never occurred in persons with paternal deletion, and were exclusively associated with maternal uniparental disomy (UPD) or imprinting abnormalities (IM). In order to gain a better understanding of the psychopathology and to further refine the psychiatric diagnosis, we describe in more detail the psychopathological manifestations of six adults with a history of psychotic episodes. All these individuals had a detailed psychiatric examination, including the use of the operational criteria (OPCRIT) checklist. An identifiable subtype of psychotic disorder was associated with PWS. Characteristics include early age of onset, acute onset, polymorphous, and shifting symptomatology and a need for psychiatric hospitalization. The presence of precipitating stress factors and a prodromal phase with physiological symptoms was reported in all patients. Current diagnostic categories do not allow an unequivocal psychiatric diagnosis.

Psychiatric disorders in Prader-Willi syndrome: epidemiology and management

Although people with intellectual disabilities are at increased risk for psychiatric disorders, the type and rate of these problems differ between those with different causes for their retardation. In this paper, we review behavioural and psychiatric problems in persons with Prader-Willi syndrome, a disorder caused by a paternally derived deletion at chromosome 15(q11-q13) in about 70% of affected patients, and by maternal uniparental disomy in the majority of the remaining patients. In addition to the syndrome's characteristic hyperphagia and food seeking, individuals with Prader-Willi syndrome also have increased risks of nonfood, compulsive behaviours. These include skin picking, which is highly prevalent, as well as more variable rates of hoarding, redoing and concerns with symmetry, exactness, cleanliness, ordering and arranging. Relative to others with mental retardation, persons with Prader-Willi syndrome are at a marked increased risk for developing full-blown, obsessive-compulsive disorder. In addition, many people with Prader-Willi syndrome show increased rates of tantrums, oppositionality and aggression. Recent findings suggest that they also have an increased risk of psychotic disorder or affective illness with a psychotic component, especially young adult patients and those with the maternal uniparental disomy as opposed to paternal deletion. Dietary approaches include a reduced-calorie diet and increased physical activity, as well as close supervision around food and keeping food locked away. To date, neither CNS stimulants nor anorectic agents have been effective in treating hyperphagia, in part because hyperphagia in Prader-Willi syndrome is attributed to decreased satiation as opposed to increased hunger. Treatment for compulsivity and maladaptive behaviours include: behavioural programming; a structured, predictable routine; extra help with transitions; family support; and pharmacotherapy. Although formal drug studies have yet to be conducted, SSRIs have been effective in reducing skin picking, compulsivity and aggressive episodes in some individuals with Prader-Willi syndrome. Atypical antipsychotics have also proven helpful in persons with psychotic features or extreme aggression and impulsivity. Largely on the basis of case studies, the risks and benefits of these and other drugs in Prader-Willi syndrome are reviewed. Drug trials that move beyond case studies and that assess the relative efficacy of behavioural treatments alone or in combination with pharmacotherapy are sorely needed.

Prader-Willi syndrome: cycloid psychosis in a genetic subtype?

Prader-Willi syndrome (PWS) is a genetically determined disorder associated with the loss of the paternal contribution to the proximal part of the long arm of chromosome 15. Its pathophysiology is dominated by hypothalamic dysfunctions. The psychopathological phenotype comprises affective and psychotic symptoms as well as an increase of pre-existent obsessive-compulsive behaviors. The present study comprises 19 PWS patients who were referred for neuropsychiatric evaluation because of psychotic deterioration. Patients were assessed by using the elements of semistructured symptom checklists. In the majority a genetic analysis was performed to detect the underlying chromosomal defect. In 16 of the 19 patients a diagnosis of cycloid psychosis could be established. The other three showed a bipolar affective disorder. Of the psychotic patients, 11 were diagnosed as UPD and one as del 15q11-13. The remaining four patients were diagnosed clinically. For various reasons the genetic etiology could not be established. In PWS patients with a psychotic disorder (cycloid psychosis) a disproportional number of UPD is found.

Prader-Willi syndrome: new insights in the behavioural and psychiatric spectrum

Prader-Willi syndrome (PWS) is a genetic disorder caused by the loss of the paternal contribution of the proximal part (15q11-q13) of the long arm of chromosome 15 (i.e. deletion, disomy and imprinting mutation). The syndrome is associated with distinct physical dysmorphism, as well as with specific behavioural and psychopathological characteristics. Psychiatric symptoms in adolescence and adulthood have been described, including acute cycloid psychosis, and obsessive compulsive, bipolar and pervasive developmental disorders. At the Centre for Human Genetics in Leuven, Belgium, 53 individuals (31 children and adolescents, and 22 adults) have been followed up for 15 years by a special multidisciplinary team. Attention was given to their medical, cognitive, behavioural and emotional development, and the evolution of psychiatric disorders in adolescence and adulthood. This study describes the psychiatric problems in four patients diagnosed with acute cycloid psychosis and traces their development from infancy to adolescence. Four other individuals needed psychiatric evaluation and treatment, and could be diagnosed as having unspecified bipolar disorder, also termed unstable mood disorder. Both groups were compared, and significant differences in early development and later evolution into adulthood were noted. The individuals with PWS who later developed psychotic episodes were described as active and extrovert toddlers, and showed autistic behaviour during their primary school education. Their intellectual functioning was in the moderate to severely retarded range. The individuals with PWS who later developed an unstable mood disorder were described as rather passive and introvert toddlers, and they presented less disturbed behaviour during their primary school education. The intellectual functioning of these subjects was in the normal to borderline range.

Prader-Willi syndrome and cycloid psychoses

The psychiatric symptomatology of people with Prader-Willi syndrome (PWS) has mainly been described in case reports and some large-scale descriptive studies. Unfortunately, there is still no systematic description of all the psychiatric symptoms which accompany this chromosomal error. Symptoms of mood disorder and anxiety dominate the picture of PWS, although some reports also mention psychotic symptoms with variations in prevalence of between 15% and 60%. The present paper presents six case reports of adult male subjects with a diagnosis of PWS and psychiatric symptoms who fulfill the criteria for cycloid psychosis (ICD-10 F.23.0). This psychotic disorder requires a specific psychopharmacological approach with mood stabilizing agents, particularly Lithium. It is concluded that subjects with PWS may be especially vulnerable to the development of cycloid psychosis, which suggests the existence of a specific 'psychopathological phenotype'.

Prader-Willi syndrome and psychotic symptoms: 2. A preliminary study of prevalence using the Psychopathology Assessment Schedule for Adults with Developmental Disability checklist

The Psychopathology Assessment Schedule for Adults with Developmental Disability (PAS-ADD) checklist was used to screen for psychotic symptoms among people with Prader-Willi syndrome (PWS) aged 16 years and over. The scoring instructions for the PAS-ADD checklist were modified to take account of knowledge about the behavioural phenotype of PWS. Using modified scoring, 6.3% of the 95 people for whom checklists were completed had a possible psychotic disorder in the month before the assessment was made. The results should be treated as a crude estimate of the prevalence of psychotic symptoms associated with PWS in adult life in view of potential biases in the sample reported. These findings lend some support to the hypothesis that PWS has a non-chance association with psychotic symptoms and that the association is not entirely accounted for by the increased prevalence of psychosis associated with intellectual disability.

Affective psychosis and Prader-Willi syndrome

Previous studies have demonstrated that maladaptive behaviours are common amongst adults with Prader-Willi syndrome (PWS). Case reports have also previously demonstrated that psychosis can occur amongst adults with PWS. The present study was undertaken in order to gain a better understanding of the psychopathology of the psychosis of PWS. Twenty-three out of 25 adults identified with PWS living in Northamptonshire, UK, agreed to participate. Comprehensive psychiatric assessments (using the PPS-LD), and measures of adaptive and maladaptive behaviours (using the AAMR-ABS) were completed. Comparisons were made for the prevalence of psychiatric disorders against those from a previous epidemiological study of adults with intellectual disability of other aetiologies from a neighbouring county. The PWS group was found to have higher rates of affective disorders (a point prevalence of 17.4%), in which psychotic symptoms were common, but similar rates of schizophrenia/delusional disorders (4.3%) compared with the comparison group. Behaviour disorders were also common. Surprisingly, none of the PWS group was found to have generalized anxiety or phobic disorders. The diagnostic criteria for the episodes including psychotic symptoms are explored. The high rates of affective disorders is of clinical (i.e. treatment) importance as well as being of academic interest with regard to the genetics of psychiatric disorders.

Prader-Willi syndrome and psychotic symptoms: 1. Case descriptions and genetic studies

Six people with Prader-Willi syndrome (PWS) who developed psychoses are described. Along with other literature reviewed in the present paper, the results imply an association between PWS and psychotic symptoms. Genetic studies were possible in five cases and SNRPN expression was examined in three cases. Maternal uniparental disomy and 15q11q13 deletions were found, demonstrating that psychotic symptoms are not associated with a single type of genetic abnormality.