Maladaptive behaviour in Prader-Willi syndrome in adult life

Hypogonadism in Women with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a rare neuroendocrine genetic syndrome. Characteristics of PWS include hyperphagia, hypotonia, and intellectual disability. Pituitary hormone deficiencies, caused by hypothalamic dysfunction, are common and hypogonadism is the most prevalent. Untreated hypogonadism can cause osteoporosis, which is already an important issue in PWS. Therefore, timely detection and treatment of hypogonadism is crucial. To increase understanding and prevent undertreatment, we (1) performed a cohort study in the Dutch PWS population, (2) thoroughly reviewed the literature on female hypogonadism in PWS and (3) provide clinical recommendations on behalf of an international expert panel. For the cohort study, we retrospectively collected results of a systematic health screening in 64 female adults with PWS, which included a medical questionnaire, medical file search, medical interview, physical examination and biochemical measurements. Our data show that hypogonadism is frequent in females with PWS (94%), but is often undiagnosed and untreated. This could be related to unfamiliarity with the syndrome, fear of behavioral changes, hygienic concerns, or drug interactions. To prevent underdiagnosis and undertreatment, we provide practical recommendations for the screening and treatment of hypogonadism in females with PWS.

Suicidality and Self-Harming Behaviors in Patients with Prader-Willi Syndrome (PWS): Case Report and Literature Review

Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder which is often associated with significant behavioral challenges and poor intellectual functioning. Research has shown that individuals with PWS are more likely to experience mental health problems, have higher relapse rates, and are at risk of self-harming behavior. Although PWS is associated with mild intellectual disability, which in itself confers a higher mortality rate, suicidality in this population is so far unreported in the literature. We present the case of an 18-year-old male patient who was admitted to our facility following exogenous insulin administration with suicidal intent. The main clinical characteristics, self-harming behaviors, and suicide risk factors of patients with PWS are discussed in this report. The article's objective is to redirect clinicians' attention to carefully screen and treat the underlying behavioral problems in PWS patients.

Hypogonadism in Adult Males with Prader-Willi Syndrome-Clinical Recommendations Based on a Dutch Cohort Study, Review of the Literature and an International Expert Panel Discussion

Prader-Willi syndrome (PWS) is a complex genetic syndrome characterized by hyperphagia, intellectual disability, hypotonia and hypothalamic dysfunction. Adults with PWS often have hormone deficiencies, hypogonadism being the most common. Untreated male hypogonadism can aggravate PWS-related health issues including muscle weakness, obesity, osteoporosis, and fatigue. Therefore, timely diagnosis and treatment of male hypogonadism is important. In this article, we share our experience with hypogonadism and its treatment in adult males with PWS and present a review of the literature. In order to report the prevalence and type of hypogonadism, treatment regimen and behavioral issues, we retrospectively collected data on medical interviews, physical examinations, biochemical measurements and testosterone replacement therapy (TRT) in 57 Dutch men with PWS. Fifty-six (98%) of the patients had either primary, central or combined hypogonadism. Untreated hypogonadism was associated with higher body mass index and lower hemoglobin concentrations. TRT was complicated by behavioral challenges in one third of the patients. Undertreatment was common and normal serum testosterone levels were achieved in only 30% of the patients. Based on the Dutch cohort data, review of the literature and an international expert panel discussion, we provide a practical algorithm for TRT in adult males with PWS in order to prevent undertreatment and related adverse health outcomes.

Characteristics and relationship between hyperphagia, anxiety, behavioral challenges and caregiver burden in Prader-Willi syndrome

Objectives

Prader-Willi syndrome (PWS) is a rare genetic disorder characterized by maladaptive behaviors, amongst which hyperphagia is a life-long concern for individuals with PWS and their caregivers. The current study examined the contribution of hyperphagia and other factors to caregiver burden across lifespan, in 204 caregivers of individuals with PWS living in the US, using the Zarit Burden Interview (ZBI) and the hyperphagia questionnaire (HQ-CT).

Results

We found a strong relationship between ZBI and HQ-CT especially in individuals with PWS older than 4 y and showed that HQ-CT scores of individuals with PWS is positively correlated with ZBI scores of their caregivers. The weight status of individuals with PWS was not associated with HQ-CT and ZBI scores, except for obese individuals who had significantly higher HQ-CT scores when compared to normal weight PWS individuals. We looked at PWS symptoms and care-related issues that impacted individuals and caregivers the most. We found that care-related tasks had the biggest negative impact on caregivers of children aged 0–4 y, whereas anxiety, temper tantrums, and oppositional behaviors of older individuals with PWS had the biggest impact on their caregivers concomitant with their high caregiver burden. Finally, we assessed the variability of HQ-CT and ZBI over 6 months in a subgroup of 83 participants. Overall, neither measure differed between 6 months and baseline. Most individual’s absolute HQ-CT score changes were between 0–2 units, whereas absolute ZBI score changes were between 0–6 points. Changes in the caregiver’s or individual’s life had little or no effect on HQ-CT and ZBI scores.

Conclusions

This study demonstrates a relationship between hyperphagia and caregiver burden and sheds light on predominant symptoms in children and adolescents that likely underly PWS caregiver burden. The stability and relationship between HQ-CT and ZBI support ZBI as an additional outcome measure in PWS clinical trials.

High levels of caregiver burden in Prader-Willi syndrome

Objectives

Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder that is characterized by hyperphagia, developmental delay, incomplete sexual development, mild-to-moderate intellectual disability, and a variety of challenging behavioral and psychiatric symptoms. The characteristics of PWS can be difficult for caregivers to cope with and are likely to cause significant and long- term caregiver burden. The current study examined burden in 142 caregivers of children and adults with PWS living in the US using the Zarit Burden Interview (ZBI). The study aimed to measure the level of burden in caregivers of individuals with PWS, to explore the impact of PWS on caregiver quality of life, and to assess ZBI as an indicator of that impact.

Results

Caregivers participating in this study were predominantly mothers, 30–59 years old, non-Hispanic Whites, married or in a relationship, with an annual household income slightly distributed towards higher income. Nearly 90% of the caregiver`s children with PWS lived at home. Caregivers experienced high caregiver burden with an average ZBI score of 44.4 ± 15.4. ZBI scores were highest for caregivers of teenage and young adult individuals with PWS (49.2 ± 14.6 and 49.2 ± 14.1, respectively), while those caring for older adults (>30) and the youngest age group had lower scores (38.6 ±10.5 and 34.8 ±12.5, respectively). Caregivers reported that caring for a person with PWS negatively impacted their romantic relationship, ability to work, sleep, and mood. Whereas we did not find strong correlations between family income or level of help the caregiver receives and ZBI scores, the results showed significant correlations and a linear relationship between ZBI scores and caregiver depressed mood, feelings of anxiety, negative romantic relationship impact, as well as sleep and work disruption.

Conclusions

Our study reveals that PWS incurs high caregiver burden and impacts many aspects of the lives of caregiver. We identified the ZBI as a good predictor of that impact. Our findings draw attention to the critical unmet need for support for caregivers of individuals with PWS.

Learning by observation and learning by doing in Prader-Willi syndrome

BACKGROUND

New competencies may be learned through active experience (learning by doing) or observation of others' experience (learning by observation). Observing another person performing a complex action accelerates the observer's acquisition of the same action, limiting the time-consuming process of learning by doing. Here, we compared learning by observation and learning by doing in individuals with Prader-Willi syndrome (PWS). It is hypothesized that PWS individuals could show more difficulties with learning by observation than learning by doing because of their specific difficulty in interpreting and using social information.

METHODS

The performance of 24 PWS individuals was compared with that of 28 mental age (MA)- and gender-matched typically developing (TD) children in tasks of learning a visuo-motor sequence by observation or by doing. To determine whether the performance pattern exhibited by PWS participants was specific to this population or whether it was a nonspecific intellectual disability effect, we compared the PWS performances with those of a third MA- and gender-matched group of individuals with Williams syndrome (WS).

RESULTS

PWS individuals were severely impaired in detecting a sequence by observation, were able to detect a sequence by doing, and became as efficient as TD children in reproducing an observed sequence after a task of learning by doing. The learning pattern of PWS children was reversed compared with that of WS individuals.

CONCLUSIONS

The observational learning deficit in PWS individuals may be rooted, at least partially, in their incapacity to understand and/or use social information.

QOL in caregivers of Japanese patients with Prader-Willi syndrome with reference to age and genotype

This study aimed to measure quality of life (QOL) of the primary family caregivers for patients with Prader–Willi syndrome (PWS). Comparisons were made between caregivers' QOL in regard to their dependents' genotype and age group. The participants with PWS consisted of 22 children (aged from 6 to 12 years) and 23 adolescents (aged from 13 to 19 years), including 6 children and 7 adolescents with maternal uniparental disomy (mUPD) and 16 children and 16 adolescents with deletion (DEL). The QOL of the primary family caregiver for each patient was assessed using the Japanese version of the WHOQOL-BREF. To examine the effect that age (children vs. adolescents) and genotype (DEL vs. mUPD) have on the QOL of caregivers, a two-way ANOVA was conducted, followed by the Bonferroni procedure to test the simple main effects. The two age groups and the two genotypes of PWS were used as independent variables and the total QOL of caregivers as a dependent variable. The two-way ANOVA (F(1, 41) = 6.98, P < 0.05), followed by the Bonferroni procedure, showed the following: the total QOL of caregivers of DEL adolescents showed little difference from that with DEL children, but the QOL of caregivers for mUPD adolescents was shown to be lower than that with mUPD children along with that of caregivers with DEL adolescents. There is hence a growing tendency for the deterioration in the QOL of caregivers to manifest itself later in the patients' adolescence, found mainly with mUPD patients. © 2014 The Authors. American Journal of Medical Genetics Published by Wiley Periodicals, Inc.

Temper outbursts in Prader-Willi syndrome: causes, behavioural and emotional sequence and responses by carers

BACKGROUND

Temper outbursts are common in Prader-Willi syndrome but rarely described in detail. This study investigated the phenomenology of temper outbursts in terms of antecedents, sequence of behaviours and emotions and intervention strategies used.

METHOD

A semi-structured interview about temper outbursts was conducted with the main carers of seven children (9.5 to 16.7 years) and seven adults (24.7 to 47.10 years) with Prader-Willi syndrome (10 male, 4 female). Reliability and validity of the interview results was established.

RESULTS

Various setting events increased and reduced the likelihood of temper outbursts. The most common antecedent was a change to routine or expectation. There were marked similarities in the sequence of behaviours and emotions during temper outbursts, with anger rising quickly followed by expressions of remorse and distress at the end of an outburst.

DISCUSSION

The sequence of behaviours and emotions within outbursts was similar to that described in temper tantrums in typical development. Cognitive and emotional processes are likely to be important in the understanding of temper outbursts with implications for early intervention.

Behavioral profile of adults with Prader-Willi syndrome: correlations with individual and environmental variables

Background

Maladaptive behavior has been reported as a phenotypical feature in Prader–Willi syndrome (PWS). It severely limits social adaptation and the quality of life of children and adults with the syndrome. Different factors have been linked with the intensity and form of these behavioral disturbances but there is no consensus about the cause. Consequently, there is still controversy regarding management strategies and there is a need for new data.

Methods

The behavior of 100 adults with PWS attending a dedicated center was assessed using the Developmental Behavior Checklist for Adults (DBC-A) and the PWS-specific Hyperphagia Questionnaire. The DBC-A was completed separately by trained caregivers at the center and relatives or caregivers in a natural setting. Genotype, gender, age, degree of obesity and cognitive impairment were analyzed as variables with a hypothetical influence on behavioral features.

Results

Patients showed a relatively high rate of behavioral disturbances other than hyperphagia. Disruptive and social relating were the highest scoring DBC-A subscales whereas anxiety/antisocial and self-absorbed were the lowest. When hospital caregiver and natural caregiver scores were compared, scores for the latter were higher for all subscales except for disruptive and anxiety/antisocial. These effects of institutional management were underlined. In the DBC-A, 22 items have descriptive indications of PWS behavior and were used for further comparisons and correlation analysis. In contrast to previous reports, rates of disturbed behavior were lower in patients with a deletion genotype. However, the behavioral profile was similar for both genotypes. No differences were found in any measurement when comparing type I and type II deletions. The other analyzed variables showed little relevance.

Conclusions

Significant rates of behavioral disorders were highlighted and their typology described in a large cohort of adults with PWS. The deletion genotype was related to a lower severity of symptoms. Some major behavioral problems, such as hyperphagia, may be well controlled if living circumstances are adapted to the specific requirements of individuals with PWS.

PET scan perfusion imaging in the Prader-Willi syndrome: new insights into the psychiatric and social disturbances

The Prader-Willi syndrome (PWS), a rare multisystem genetic disease, leads to severe disabilities, such as morbid obesity, endocrine dysfunctions, psychiatric disorders, and social disturbances. We explored the whole brain of patients with PWS to detect abnormalities that might explain the behavioral and social disturbances, as well as the psychiatric disorders of these patients. Nine patients with PWS (six males, three females; mean age 16.4 years) underwent a positron emission tomography (PET) scan with H(2)(15)O as a tracer to measure regional cerebral blood flow (rCBF). The images were compared with those acquired from nine controls (six males, three females; mean age 21.2 years). A morphologic magnetic resonance imaging (MRI) was also performed in PWS patients, and their cognitive and behavioral skills were assessed with Wechsler Intelligence Scale for Children III and the Child Behavior Check List (CBCL). The MRI images showed no evident anatomic abnormalities, whereas PET scans revealed hypoperfused brain regions in PWS patients compared with controls, particularly in the anterior cingulum and superior temporal regions. We observed a significant relationship (P<0.05) between rCBF in the hypoperfused regions and CBCL scores. The functional consequences of these perfusion abnormalities in specific brain regions might explain the behavioral and social problems observed in these individuals.

Clinical and genetic analysis for four Chinese families with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a complex, genetic, multisystem disorder. Its major clinical features include neonatal hypotonia and failure to thrive, mental retardation, hypogonadism, short hands and feet, hyperphagia-caused obesity, and characteristic appearance. The genetic basis of PWS is also complex. It is caused by the absence of expression of the active paternal genes such as the SNRPN, NDN, and possibly others in the PWS critical region on 15q11-13. PWS is in effect a contiguous gene syndrome resulting from deletion of the paternal copies of the imprinted. Consensus in clinical diagnostic criteria was established in 1993. However, identifying relevant patients for tests remains a challenge for most practitioners, as many features of the disorder are nonspecific, and others can be subtle or evolved over time. Consequently, molecular genetic tests can be used to diagnose PWS accurately, allowing early diagnosis of the syndrome. High resolution G-banding, high resolution cytogenetic methylation-specific PCR (MS-PCR), and fluorescence in situ hybridization (FISH) are routinely used to diagnose PWS. In this study, four Chinese patients, with typical PWS features, were detected by MS-PCR and FISH. Three were cytogenetically normal, but lacked paternal expression of proximal chromosome 15q because of maternal uniparental disomy (UPD). The other one, however, demonstrated an unbalanced de novo translocation 46, XX, t (7; 15).

The prevalence and phenomenology of repetitive behavior in genetic syndromes

We investigated the prevalence and phenomenology of repetitive behavior in genetic syndromes to detail profiles of behavior. The Repetitive Behaviour Questionnaire (RBQ) provides fine-grained identification of repetitive behaviors. The RBQ was employed to examine repetitive behavior in Angelman (N = 104), Cornelia de Lange (N = 101), Cri-du-Chat (N = 58), Fragile X (N = 191), Prader-Willi (N = 189), Lowe (N = 56) and Smith-Magenis (N = 42) syndromes and individuals with intellectual disability of heterogeneous aetiology (N = 56). Repetitive behavior was variable across syndromes. Fragile X syndrome scored highly on all subscales. Angelman syndrome demonstrated a significantly lowered probability for most behaviors. Prader-Willi, Cri-du-Chat and Smith-Magenis syndrome evidenced unique profiles of repetitive behavior. There is extreme heterogeneity of repetitive behavior across genetic syndromes, highlighting syndrome specific profiles.

Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a highly variable genetic disorder affecting multiple body systems whose most consistent major manifestations include hypotonia with poor suck and poor weight gain in infancy; mild mental retardation, hypogonadism, growth hormone insufficiency causing short stature for the family, early childhood-onset hyperphagia and obesity, characteristic appearance, and behavioral and sometimes psychiatric disturbance. Many more minor characteristics can be helpful in diagnosis and important in management. PWS is an example of a genetic condition involving genomic imprinting. It can occur by three main mechanisms, which lead to absence of expression of paternally inherited genes in the 15q11.2-q13 region: paternal microdeletion, maternal uniparental disomy, and imprinting defect.

Epidemiology and Etiology of Mental Retardation

Mental retardation (MR) is a manifestation of a heterogeneous set of impairments and conditions that result in cognitive limitation. It is a condition of medical, educational, and social importance. Physicians identify profound, severe, and moderate MR but rarely diagnose mild MR unless it is associated with a genetic or medical syndrome. From a medical perspective, the quest for etiology and the possibility of medical or surgical intervention to minimize deterioration are paramount. Educators, on the other hand are less concerned with causation than with academic achievement and school success. The majority of cases of mild MR is identified in school settings. Finally, the public uses the label to describe poor adaptive skills. Adults with MR who hold jobs, live independently, and participate in society are not always described as having MR. Thus some individuals characterized in childhood or adolescence as having mild MR become indistinguishable from the general population in adulthood.

Factor analysis of the aberrant behavior checklist in individuals with autism spectrum disorders

Exploratory factor analysis (varimax and promax rotations) of the aberrant behavior checklist-community version (ABC) in 275 individuals with Autism spectrum disorder (ASD) identified four- and five-factor solutions which accounted for >70% of the variance. Confirmatory factor analysis (Lisrel 8.7) revealed indices of moderate fit for the five-factor solution. Our results suggest that the factor structure of the ABC is robust within an ASD sample. Both solutions yielded a three items self-injury factor. Stratifying on this factor, we identified significant differences between the high- and low-self injury groups on ABC subscales. The emergence of a self-injury factor, while not suggestive of a new subscale, warrants further exploration as a tool that could help dissect relevant neurobiobehavioral groups in ASD.

Maladaptive behaviors and risk factors among the genetic subtypes of Prader-Willi syndrome

Maladaptive behaviors among 65 people with Prader-Willi syndrome were assessed using the Reiss Screen for maladaptive behaviors. Young adults in their twenties were more likely to display aggressive behavior than adolescents and older adults. Differences in maladaptive behaviors between the typical deletion and uniparental disomy (UPD) subtypes were evaluated. The typical deletion subtype had higher self-injury and stealing scores than the UPD subtype. Subject characteristics were differentially related to maladaptive behavior among the typical deletion and UPD subtypes. Differences in maladaptive behavior were also examined between the typical deletion type I and type II subtypes. The type I deletion subtype had greater physical depression scores than the type II deletion subtype. The Reiss Screen cut-off scores were used to determine whether differences occurred between the subtypes at a clinically significant level. These findings offer insight into the health care needs of people with PWS.

An investigation of executive function abilities in adults with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of expression of maternally imprinted genes on the long arm of chromosome 15 (15q 11-13). There are two main genetic sub-types: (1) deletion, caused by the absence of paternally derived genetic material; and (2) uniparental disomy (UPD), where two copies of maternally derived chromosome 15 are present. In addition to generally mild/borderline intellectual disability (ID) and the almost universal feature of hyperphagia, PWS is associated with high rates of behaviour problems including temper tantrums, compulsive behaviour, perseverative speech, skin picking and rigid thinking. The present study seeks to explore whether these behaviours are associated with relative deficits in executive function (EF), which comprises the set of non-automatic processes utilized by an individual when faced with a novel situation.

METHODS

Eighteen adult participants with a clinical diagnosis of PWS (12 with deletion sub-type, 6 with UPD) were recruited from a UK Health Service PWS clinic, and compared with 15 participants of similar age and verbal ability on a series of EF tasks and also Digit Span Forwards. An informant completed two ratings of behaviour, the Aberrant Behavior Checklist (ABC) and the Dysexecutive Questionnaire (DEX).

RESULTS

The PWS group had significantly higher scores on the ABC but not on the DEX. There were no significant differences between the whole PWS group and the comparison group on any of the EF tasks. The deletion sub-type group was significantly poorer at a non-executive task, Digit Span Forwards. There was an unexpected trend for the deletion sub-type group to show more efficient performance on a visuospatial planning task, the Tower of London (TOL), but this trend did not reach significance.

CONCLUSIONS

The lack of relative deficits in EF task performance does not support the hypothesis that EF differences could account for the high levels of behaviour problems found in PWS. Applying the Baddeley and Hitch model of working memory it is suggested that the PWS group have a relatively intact central executive and visuospatial sketchpad but a relative impairment in the phonological loop, perhaps relating to the capacity of the phonological store. This latter finding seems to be particularly salient for those with a deletion. As differences in EF ability were not found, it is suggested that a region of the brain involved in the modulation of emotion but not particularly with EF, the orbitofrontal cortex (OFC), may be implicated in the behaviour problems reported in PWS.

Rituals and compulsivity in Prader-Willi syndrome: profile and stability

BACKGROUND

Prader-Willi syndrome (PWS) is characterized by an increased risk for obsessive-compulsive disorder. This study investigated the nature of compulsive-like behaviours in the PWS.

METHOD

Parents of 50 individuals with PWS (aged 5-18 years) and 50 typically developing 4-year-old children completed the Childhood Routines Inventory. This instrument measures compulsive-like behaviours in normative childhood.

RESULTS

Many childhood compulsive behaviours are prevalent among older children and adolescents with PWS. Group differences were observed in that the PWS group, independent of age, gender and cognitive dysfunctions, exhibited more intense compulsive behaviours related to insistence on sameness in many daily activities and social contexts. Findings also revealed an age-independent low-prevalent pattern of PWS compulsivity, probably related to other features in the PWS symptomatology.

CONCLUSIONS

Compulsions of childhood do not subside with age in adolescents with PWS. The findings indicate that the differentiation between delayed childhood rituals and pathological manifestations of compulsive features is complex in PWS populations.

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: 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.

Emergence of compulsive behavior and tantrums in children with Prader-Willi syndrome

Many adults with Prader-Willi syndrome are affected by behaviors such as tantrums, skin-picking, and compulsions. The nature and extent of these problems suggest more attention be directed to their emergence in childhood. Our purpose was to investigate behavior problems in children with this syndrome and identify the age at which these behaviors emerge. Parents of children with Prader-Willi syndrome, Down syndrome, and those developing typically completed questionnaires. Children with Prader-Willi syndrome exhibited more compulsions, skin-picking, and tantrums than did the other groups. A discriminant analysis of behavior variables derived two statistically significant functions that were interpreted as developmental milestones and problematic behavior. These functions correctly predicted membership for 79% of grouped cases.

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.