'Pfropfschizophrenie' revisited. Schizophrenia in people with mild learning disability

Clinical, cognitive and neuroanatomical associations of serum NMDAR autoantibodies in people at clinical high risk for psychosis

Serum neuronal autoantibodies, such as those to the NMDA receptor (NMDAR), are detectable in a subgroup of patients with psychotic disorders. It is not known if they are present before the onset of psychosis or whether they are associated with particular clinical features or outcomes. In a case-control study, sera from 254 subjects at clinical high risk (CHR) for psychosis and 116 healthy volunteers were tested for antibodies against multiple neuronal antigens implicated in CNS autoimmune disorders, using fixed and live cell-based assays (CBAs). Within the CHR group, the relationship between NMDAR antibodies and symptoms, cognitive function and clinical outcomes over 24 month follow-up was examined. CHR subjects were not more frequently seropositive for neuronal autoantibodies than controls (8.3% vs. 5.2%; OR = 1.50; 95% CI: 0.58-3.90). The NMDAR was the most common target antigen and NMDAR IgGs were more sensitively detected with live versus fixed CBAs (p < 0.001). Preliminary phenotypic analyses revealed that within the CHR sample, the NMDAR antibody seropositive subjects had higher levels of current depression, performed worse on the Rey Auditory Verbal Learning Task (p < 0.05), and had a markedly lower IQ (p < 0.01). NMDAR IgGs were not more frequent in subjects who later became psychotic than those who did not. NMDAR antibody serostatus and titre was associated with poorer levels of functioning at follow-up (p < 0.05) and the presence of a neuronal autoantibody was associated with larger amygdala volumes (p < 0.05). Altogether, these findings demonstrate that NMDAR autoantibodies are detectable in a subgroup of CHR subjects at equal rates to controls. In the CHR group, they are associated with affective psychopathology, impairments in verbal memory, and overall cognitive function: these findings are qualitatively and individually similar to core features of autoimmune encephalitis and/or animal models of NMDAR antibody-mediated CNS disease. Overall the current work supports further evaluation of NMDAR autoantibodies as a possible prognostic biomarker and aetiological factor in a subset of people already meeting CHR criteria.

Prevalence of co-occurring psychiatric disorders in adults and adolescents with intellectual disability: A systematic review and meta-analysis

BACKGROUND

Subjects with intellectual disability (ID) are vulnerable to experience psychiatric disorders. The present authors performed a systematic review and meta-analysis to estimate the prevalence of co-occurring psychiatric disorders, excluding co-occurring autism spectrum disorders, in subjects with intellectual disability.

METHOD

The present authors performed a random-effects meta-analysis of the prevalence of psychiatric disorders in adults and adolescents with intellectual disability.

RESULTS

Twenty-two studies were included. The pooled prevalence of any co-occurring psychiatric disorders in intellectual disability was 33.6% (95% CI: 25.2%-43.1%) with high heterogeneity but no publication bias. Prevalence was lower in population-based studies, in studies that used ICD criteria for the psychopathology and in studies with low risk of bias. The prevalence was higher in mild, moderate and severe intellectual disability than in profound intellectual disability.

CONCLUSIONS

Psychiatric disorders are common in subjects with intellectual disability, and the present authors found that clinical and methodological moderators affect the pooled prevalence.

Neuropsychiatric Aspects in Men with Klinefelter Syndrome

BACKGROUND AND OBJECTIVE

Klinefelter Syndrome (KS) is the most common sex chromosome aneuploidy (47, XXY) and cause of male hypergonadotropic hypogonadism. It is characterized by an extreme clinical heterogeneity in presentation, including infertility, hypogonadism, language delay, metabolic comorbidities, and neurocognitive and psychiatric disorders. Since testosterone is known to have organizational, neurotrophic and neuroprotective effects on brain, the condition of primary hypogonadism could play a role. Moreover, given that KS subjects have an additional X, genes on the extra-chromosome could also exert a significant impact. The aim of this narrative review is to analyze the available literature on the relationship between KS and neuropsychiatric disorders.

METHODS

To extend to the best of published literature on the topic, appropriate keywords and MeSH terms were identified and searched in Pubmed. Finally, references of original articles and reviews were examined.

RESULTS

Both morphological and functional studies focusing on the brain showed that there were important differences in brain structure of KS subjects. Different psychiatric disorders such as Schizophrenia, autism, attention deficit hyperactivity disorder, depression and anxiety were frequently reported in KS patients according to a broad spectrum of phenotypes. T supplementation (TRT) was not able to improve the psychotic disorders in KS men with or without overt hypogonadism.

CONCLUSION

Although the risk of psychosis, depression and autism is increased in subjects with KS, no definitive evidence has been found in studies aiming at identifying the relationship between aneuploidy, T deficit and the risk of psychiatric and cognitive disorders in subjects affected by KS.

Comprehensive health care services for people with learning disabilities

Comprehensive health care services respond effectively to the needs of their patients not just in terms of treatment of health problems but also by addressing overall well-being by understanding, informing, involving, counselling and respecting the individual. By contrast, the history of health care for people with learning disabilities has been characterised by a lack of communication and poor understanding of their ordinary and special needs. There have been many barriers to access to health services that most members of the population take for granted. In addition, people with learning disabilities have many special health care needs that also have to be addressed. Therefore, person-centred services must be aware of the wide range of needs to which they must be able to respond while treating each person as an individual (see Box 1).

Epidemiology of mental health problems in adults with learning disability: an update

Epidemiological studies measuring prevalence rates and factors associated with mental health problems in adults with learning disability have produced very different and sometimes contradictory results, mainly because of methodological problems. Consequently, much of the epidemiology of mental health problems in this population is still unknown, although improved methodology and additional information are emerging. This article describes the methodological difficulties of studies, the reported prevalence rates in the context of these difficulties and what is currently known about the factors associated with mental health problems in this population.

Psychiatric assertive outreach and learning disability services

Assertive outreach is a well-established method of managing patients with severe mental illness in the community. However, there is limited application and evidence of its efficacy in services for people with learning disabilities who also have mental illness. This paper elucidates current service provision for this group of patients and illustrates the pathways to mental health care available to them.

The contribution of rare variants to risk of schizophrenia in individuals with and without intellectual disability

By performing a meta-analysis of rare coding variants in whole-exome sequences from 4,133 schizophrenia cases and 9,274 controls, de novo mutations in 1,077 family trios, and copy number variants from 6,882 cases and 11,255 controls, we show that individuals with schizophrenia carry a significant burden of rare, damaging variants in 3,488 genes previously identified as having a near-complete depletion of loss-of-function variants. In patients with schizophrenia who also have intellectual disability, this burden is concentrated in risk genes associated with neurodevelopmental disorders. After excluding known risk genes for neurodevelopmental disorders, a significant rare variant burden persists in other genes intolerant of loss-of-function variants; although this effect is notably stronger in patients with both schizophrenia and intellectual disability, it is also seen in patients with schizophrenia who do not have intellectual disability. Together, our results show that rare, damaging variants contribute to the risk of schizophrenia both with and without intellectual disability and support an overlap of genetic risk between schizophrenia and other neurodevelopmental disorders.

Structural coding versus free-energy predictive coding

Focusing on visual perceptual organization, this article contrasts the free-energy (FE) version of predictive coding (a recent Bayesian approach) to structural coding (a long-standing representational approach). Both use free-energy minimization as metaphor for processing in the brain, but their formal elaborations of this metaphor are fundamentally different. FE predictive coding formalizes it by minimization of prediction errors, whereas structural coding formalizes it by minimization of the descriptive complexity of predictions. Here, both sides are evaluated. A conclusion regarding competence is that FE predictive coding uses a powerful modeling technique, but that structural coding has more explanatory power. A conclusion regarding performance is that FE predictive coding-though more detailed in its account of neurophysiological data-provides a less compelling cognitive architecture than that of structural coding, which, for instance, supplies formal support for the computationally powerful role it attributes to neuronal synchronization.

Nurses' perceptions of personal attributes required when working with people with a learning disability and an offending background: a qualitative study

WHAT IS KNOWN ON THE SUBJECT?: Learning disability nursing in the area of people with a learning disability and an offending background has developed considerably over recent years, particularly since the publication of the Bradley (). There has been limited work into the competencies nurses require to work in this area, and even less about the personal attributes of learning disability nurses. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Learning disability nursing's specific contribution to the care of this population lies in their knowledge of the interaction between the learning disability, an individual's, sometimes abusive, personal history and an understanding of the subsequent offending behaviour. The knowledge base of nurses working with people with learning disabilities and an offending background needs to reflect the changing service user group. This is particularly in relation to substance misuse, borderline personality disorder, and mental health and the way such factors inter-relate with the learning disability. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Further research is required into the relationship among decision making, risk taking or reluctance to do this, and the personal attributes required by nurses to work in secure learning disability care. Learning disability secure services are likely to continue to undergo change as circumstances alter and the offending population demonstrate greater complexity; nursing competencies and personal attributes need similarly to adapt to such changes. Mental health nursing has a great deal to contribute to effective working with this population, specifically with regard to developing strong relationships when concerns around borderline personality disorder or substance misuse are particularly in evidence.

ABSTRACT

Aim To identify and discuss the personal attributes required by learning disability nurses to work effectively with people with an offending background in secure and community settings. Background This study was part of a larger research investigation into the nursing competencies required to work with people with an offending background. There are few existing studies examining the personal attributes necessary for working with this group. Design A qualitative study addressing the perceptions of nurses around the personal attributes required to work with people with learning disabilities and an offending background. Methods A semi-structured interview schedule was devised and constructed, and 39 individual interviews were subsequently undertaken with learning disability nurses working in high, medium, low secure and community settings. Data were collected over 1 year in 2010/11 and analysed using a structured thematic analysis supported by the software package MAXqda. Findings The thematic analysis produced three categories of personal attributes, named as looking deeper, achieving balance and connecting, each of which contained a further three sub-categories. Conclusion Nursing of those with a learning disability and an offending background continues to develop. The interplay among personal history, additional background factors, nurses' personal attributes and learning disability is critical for effective relationship building.

Differences in cognitive impairment between schizophrenia and bipolar disorder: Considering the role of heterogeneity

Schizophrenia is associated with significant cognitive impairment. Bipolar disorder (BD) also presents with cognitive deficits that are similar to, albeit less severe, than those reported in schizophrenia. There has been controversy over whether selective deficits in social cognition or developmental trajectory of cognitive deficits can distinguish schizophrenia from BD. Also, available studies have not generally considered the potential effect of cognitive heterogeneity within the two disorders on between-group differences. The current review examines the evidence on the specificity of social cognitive deficits and early neurocognitive impairment to schizophrenia and explores the overall outcome of studies investigating within and cross-diagnosis cognitive heterogeneity in schizophrenia and BD. Current evidence does not support the specificity of social cognitive impairment to schizophrenia. Available studies also suggest that cognitive impairment in premorbid and early stages is evident not only in schizophrenia but also in many BD patients. Both schizophrenia and BD have a number of cognitive subgroups, including severe impairment, good functioning, and one or more selective or modest impairment clusters. While both disorders are represented in each cognitive subgroup, there are significant cross-diagnostic differences regarding prevalences of individuals belonging to the severe impairment and good functioning subgroups. Individuals with schizophrenia are much more likely to exhibit severe cognitive impairment than individuals with BD and good cognitive functioning is more often observed in BD patients than schizophrenia patients. Further identification of the neurobiological and genetic characteristics of the cognitive subgroups in major psychoses can improve the validity of diagnostic systems and can advance the development of personalized management approaches, including cognitive remediation.

Towards diagnostic markers for the psychoses

Psychotic disorders are currently grouped under broad phenomenological diagnostic rubrics. Researchers hope that progress in identifying aetiological mechanisms will ultimately enable more precise division of heterogeneous diagnoses into specific and valid subgroups. This goal has been an aim of psychiatry since the 19th century, when patients with general paresis were thought to have "insanity" similar to dementia praecox and manic depressive illness. Nowadays, the constructs of organic-induced and substance-induced psychotic disorder show that our diagnostic classification system already reflects, in part, aetiological factors. Most recently, gene copy number variation and autoimmunity have been associated with schizophrenia. We suggest how, on the basis of recent scientific advances, we can progress the identification of further putative subgroups and make the most of currently available interventions. Prompt diagnosis and treatment, and a more routine search for causes, could preserve function and improve outcome, and therefore be more acceptable to patients and carers.

Facial, vocal and cross-modal emotion processing in early-onset schizophrenia spectrum disorders

Recognition of emotional expressions plays an essential role in children's healthy development. Anomalies in these skills may result in empathy deficits, social interaction difficulties and premorbid emotional problems in children and adolescents with schizophrenia. Twenty-six subjects with early onset schizophrenia spectrum (EOSS) disorders and twenty-eight matched healthy controls (HC) were instructed to identify five basic emotions and a neutral expression. The assessment entailed presenting visual, auditory and congruent cross-modal stimuli. Using a generalized linear mixed model, we found no significant association for handedness, age or gender. However, significant associations emerged for emotion type, perception modality, and group. EOSS patients performed worse than HC in uni- and cross-modal emotional tasks with a specific negative emotion processing impairment pattern. There was no relationship between emotion identification scores and positive or negative symptoms, self-reported empathy traits or a positive history of developmental disorders. However, we found a significant association between emotional identification scores and nonverbal communication impairments. We conclude that cumulative dysfunctions in both nonverbal communication and emotion processing contribute to the social vulnerability and morbidity found in youths who display EOSS disorder.

De novo mutations from sporadic schizophrenia cases highlight important signaling genes in an independent sample

Schizophrenia is a debilitating syndrome with high heritability. Genomic studies reveal more than a hundred genetic variants, largely nonspecific and of small effect size, and not accounting for its high heritability. De novo mutations are one mechanism whereby disease related alleles may be introduced into the population, although these have not been leveraged to explore the disease in general samples. This paper describes a framework to find high impact genes for schizophrenia. This study consists of two different datasets. First, whole exome sequencing was conducted to identify disruptive de novo mutations in 14 complete parent-offspring trios with sporadic schizophrenia from Jerusalem, which identified 5 sporadic cases with de novo gene mutations in 5 different genes (PTPRG, TGM5, SLC39A13, BTK, CDKN3). Next, targeted exome capture of these genes was conducted in 48 well-characterized, unrelated, ethnically diverse schizophrenia cases, recruited and characterized by the same research team in New York (NY sample), which demonstrated extremely rare and potentially damaging variants in three of the five genes (MAF<0.01) in 12/48 cases (25%); including PTPRG (5 cases), SCL39A13 (4 cases) and TGM5 (4 cases), a higher number than usually identified by whole exome sequencing. Cases differed in cognition and illness features based on which mutation-enriched gene they carried. Functional de novo mutations in protein-interaction domains in sporadic schizophrenia can illuminate risk genes that increase the propensity to develop schizophrenia across ethnicities.

Developmental trajectory of cognitive impairment in bipolar disorder: comparison with schizophrenia

Both schizophrenia and bipolar disorder (BP) are associated with neurocognitive deficits. However, it has been suggested that schizophrenia, but not BP, is characterised by premorbid cognitive impairments and neurodevelopmental abnormalities. In this paper, studies investigating neurocognitive deficits in premorbid, high-risk and first-episode BP were reviewed and these findings were compared with outcome of studies in schizophrenia. Available evidence suggests that cognitive deficits are evident in first-episode BP and such deficits can be evident even years before the onset of the illness in some patients. Trajectory of cognitive deficits from childhood to adulthood can be very similar in schizophrenia and many patients with BP. Developmental lag in acquisition of cognitive skills is a risk factor for both disorders. However, unlike schizophrenia, not only impaired cognition but also supranormal premorbid cognitive/scholastic performance predict BP. Neurodevelopmental cognitive impairment is evident in some but not all patients with BP. A model suggesting that only BP patients who share common genetic risk factors with schizophrenia have premorbid neurodevelopmental cognitive deficits is proposed. In this model, combination of absence of neurodevelopmental abnormalities and BP-related temperamental characteristics explains the relationship between supranormal cognition and risk for BP.

Neurodevelopmental origin of cognitive impairment in schizophrenia

Cognitive impairment is a common feature of schizophrenia; however, its origin remains controversial. Neurodevelopmental abnormalities clearly play a role in pre-morbid cognitive dysfunction in schizophrenia, yet many authors believe that schizophrenia is characterized by illness-related cognitive decline before and after onset of the psychosis that can be the result of neurodegenerative changes. The main reasons behinds such arguments include, first, the evidence showing that effect sizes of the cognitive deficits in subjects who develop adult schizophrenia gradually increase in the first two decades of life and, second, the fact that there is functional decline in many patients with schizophrenia over the years. In this Editorial, I argue that current evidence suggests that illness-related cognitive impairment is neurodevelopmental in origin and characterized by slower gain (developmental lag) but not cognitive decline continuing throughout the first two decades of life. I introduce a model suggesting that neurodevelopmental abnormality can in fact explain the course of cognitive dysfunction and variations in the trajectory of functional decline throughout the life in individuals with schizophrenia. In this model, the severity of underlying neurodevelopmental abnormality determines the age that cognitive deficits first become apparent and contributes to the cognitive reserve of the individual. Interaction of neurodevelopmental abnormality with clinical symptoms, especially negative symptoms and aging, vascular changes, psychological and iatrogenic factors contributes to the heterogeneity of the functional trajectory observed in this disorder.

A genome wide survey supports the involvement of large copy number variants in schizophrenia with and without intellectual disability

BACKGROUND

Copy number variants (CNVs) have been shown to play a role in schizophrenia and intellectual disability.

METHODS

We compared the CNV burden in 66 patients with intellectual disability and no symptoms of psychosis (ID-only) with the burden in 64 patients with intellectual disability and schizophrenia (ID + SCZ). Samples were genotyped on three plates by the Broad Institute using the Affymetrix 6.0 array.

RESULTS

For CNVs larger than 100 kb, there was no difference in the CNV burden of ID-only and ID + SCZ. In contrast, the number of duplications larger than 1 Mb was increased in ID + SCZ compared to ID-only. We detected seven large duplications and two large deletions at chromosome 15q11.2 (18.5-20.1 Mb) which were all present in patients with ID + SCZ. The involvement of this region in schizophrenia was confirmed in Scottish samples from the ISC study (N = 2,114; 1,130 cases and 984 controls). Finally, one of the patients with schizophrenia and low IQ carrying a duplication at 15q11.2, is a member of a previously described pedigree with multiple cases of mild intellectual disability, schizophrenia, hearing impairment, retinitis pigmentosa and cataracts. DNA samples were available for 11 members of this family and the duplication was present in all 10 affected individuals and was absent in an unaffected individual.

CONCLUSIONS

Duplications at 15q11.2 (18.5-20.1 Mb) are highly prevalent in a severe group of patients characterized by intellectual disability and comorbid schizophrenia. It is also associated with a phenotype that includes schizophrenia, low IQ, hearing and visual impairments resembling the spectrum of symptoms described in "ciliopathies."

A rising tide: the increasing age and psychiatric length of stay for individuals with mild intellectual disabilities

BACKGROUND

It is unclear whether the substantial decline in number and duration of admissions for patients with intellectual disability (ID) have occurred uniformly over time with respect to age, gender, severity of disability, legal status and location of treatment.

METHOD

A retrospective analysis of NHS (National Health Service) admissions for ID and use of NHS ID beds in England between 1998/9 and 2007/8.

RESULTS

NHS admissions for ID halved from 37,736 to 18,091, and admissions with a primary diagnosis of ID to beds reduced by 71% from 21,866 to 6420. This reduction was most marked among children with the result that the average age of those admitted increased from 26 years to 36 years. Mean length of stay shortened except for mild ID where it increased from 131 days to 244 days (the median increased from 6 days to 32 days). There was an 18% reduction in the number of patients with ID who were legally detained to NHS facilities but a 170% increase in those to private facilities (from 202 to 545).

CONCLUSIONS

The number of patients with ID admitted to NHS facilities, especially children, has fallen dramatically. There has been a marked shift towards legal detentions to private facilities. The most notable finding was the increased duration of admissions for those with mild ID, possibly indicating that substituting mainstream for specialist services for this group has had negative consequences.

Longitudinal gray matter change in young people who are at enhanced risk of schizophrenia due to intellectual impairment

BACKGROUND

Existing studies of brain structural changes before the onset of schizophrenia have considered individuals with either familial risk factors or prodromal symptomatology. We aimed to determine whether findings from these studies are also applicable to those at enhanced risk of developing schizophrenia for another reason-intellectual impairment.

METHODS

Participants with intellectual impairment (mean IQ: 78.2) received magnetic resonance imaging of the brain at baseline (mean age: 16 years old) and again 6 years later. The Positive and Negative Syndrome Scale was used to assess psychotic symptoms. Participants were dichotomized using their Positive and Negative Syndrome Scale scores at follow-up and gray matter changes were compared between the groups using tensor based morphometry and semiautomated region of interest analysis.

RESULTS

Forty-six individuals had scans of sufficient quality to be included in the study. The tensor based morphometry analyses revealed that those with psychotic symptoms at follow-up showed significantly greater gray matter reductions over 6 years in the medial temporal lobes bilaterally. Region of interest analyses revealed that those individuals with psychotic symptoms at follow-up showed a reduced right hippocampal volume at age 16 and reduced bilateral hippocampal volumes at follow-up.

CONCLUSIONS

This unique study of individuals vulnerable to schizophrenia due to intellectual impairment highlights aberrant development in the medial temporal lobe associated with the occurrence of psychotic symptoms. These developmental changes are also evident in populations at enhanced risk of schizophrenia for familial and symptomatic reasons, suggesting they are central to the development of the disorder regardless of the nature of the vulnerability state.

Differential relationship between neurological and cognitive dysfunction in first episode psychosis patients and in healthy individuals

The minor neurological and cognitive deficits consistently reported in psychoses may reflect the same underlying brain dysfunction. Still, even in healthy individuals minor neurological abnormalities are associated with worse cognitive function. Therefore, establishing which neurological and cognitive deficits are specific to psychosis is essential to inform the pathophysiology of this disorder. We evaluated a large epidemiological sample of patients with first episode psychosis (n=242) and a population-based sample of healthy individuals (n=155), as part of the AESOP study. We examined neurological soft signs using the Neurological Evaluation Scale (Buchanan and Heinrichs, 1989), and generalized and specific cognitive deficits (memory; verbal abilities; attention, concentration and mental speed; executive functions and working memory; language; visual constructual/perceptual abilities). In patients, more neurological signs across all subscales were associated with worse general cognitive function, while in controls this was only present for sensory integration and sequencing signs. Furthermore, in patients, but not in healthy individuals, more sensory integrative signs were associated with deficits in specific cognitive domains, such as memory, verbal abilities, language, visual/perceptual, executive function (p ranging <0.001-0.002); sequencing signs with language, executive function, and attention (p<0.001-0.004); and motor signs with poorer verbal abilities (p=0.001). These findings indicate the presence of specific associations between neurological and cognitive deficits in psychosis that are distinct from those of healthy individuals.

Intellectual disability and major psychiatric disorders: a continuum of neurodevelopmental causality

There is accumulating evidence for shared genetic as well as environmental risk between intellectual disability and other conditions with a neurodevelopmental basis such as autism, attention-deficit hyperactivity disorder, epilepsy and schizophrenia. These can be conceived as lying along a continuum of genetically and environmentally induced neurodevelopmental causality.

Progress in defining the biological causes of schizophrenia. Expert Rev Mol Med. 2011;13:e25. [PMID: 21794196 DOI: 10.1017/s1462399411001955]

Schizophrenia is a common mental illness resulting from a complex interplay of genetic and environmental risk factors. Establishing its primary molecular and cellular aetiopathologies has proved difficult. However, this is a vital step towards the rational development of useful disease biomarkers and new therapeutic strategies. The advent and large-scale application of genomic, transcriptomic, proteomic and metabolomic technologies are generating data sets required to achieve this goal. This discovery phase, typified by its objective and hypothesis-free approach, is described in the first part of the review. The accumulating biological information, when viewed as a whole, reveals a number of biological process and subcellular locations that contribute to schizophrenia causation. The data also show that each technique targets different aspects of central nervous system function in the disease state. In the second part of the review, key schizophrenia candidate genes are discussed more fully. Two higher-order processes - adult neurogenesis and inflammation - that appear to have pathological relevance are also described in detail. Finally, three areas where progress would have a large impact on schizophrenia biology are discussed: deducing the causes of schizophrenia in the individual, explaining the phenomenon of cross-disorder risk factors, and distinguishing causative disease factors from those that are reactive or compensatory.

Genomic copy number variation in disorders of cognitive development

OBJECTIVE

To highlight recent discoveries in the area of genomic copy number variation in neuropsychiatric disorders including intellectual disability, autism, and schizophrenia. To emphasize new principles emerging from this area, involving the genetic architecture of disease, pathophysiology, and diagnosis.

METHOD

Review of studies published in PubMed including classic studies of genomic disorders and microarray and copy number studies in normal controls, intellectual disability, autism, and schizophrenia.

RESULTS

The advent of novel microarray technology has led to a revolution in the discovery of classic and novel copy number variants (CNVs) in various disorders affecting cognitive development. Across autism and schizophrenia, global CNV burden and de novo CNV burden are associated with disease. Also, specific recurrent CNVs may be associated with several DSM conditions. Each condition is also associated with heterogeneous and individually rare CNVs.

CONCLUSIONS

CNVs play an important role in the genetic architecture of the childhood neuropsychiatric disorders discussed. This discovery appears to suggest an important role for the strict regulation of gene dosage in the neurodevelopmental roots of these conditions. Microarrays have emerged as high-yield tests in the diagnosis and molecular subtyping of the childhood-onset disorders involving cognitive development. In summary, CNV studies in disorders of cognitive development have revealed interesting and important new insights and have opened an avenue of investigation that holds great promise for neuropsychiatric disease.

Dual diagnosis: A national study of psychiatric hospitalization patterns of people with developmental disability

OBJECTIVE

To report national demographics and diagnostic profiles of people with developmental disability hospitalized for psychiatric reasons, and to contrast results to psychiatric hospitalizations among patients with no comorbid developmental disability.

METHOD

People with developmental disability across Canada were identified using data administered by the Canadian Institute for Health Information. Among this cohort of people with developmental disability, records of hospitalization for psychiatric reasons were aggregated for the 2005/06 fiscal year (April 2005 to March 2006). Descriptive statistics on province of residence, age, sex, specific diagnoses, length of stay, and hospitalization frequency were calculated and compared with people without developmental disability.

RESULTS

In Canada, people with developmental disability were hospitalized a total of 8378 times in 2005/06; among these, 3478 (42%) were for psychiatric conditions. The number of people with developmental disability hospitalized for a psychiatric condition represents about 2% of the general population hospitalized for such conditions. Among people with developmental disability hospitalized for a psychiatric condition most were men and people aged between 15 and 34 years. For almost all psychiatric disorder categories, people with developmental disability were hospitalized at rates significantly different than their counterparts without developmental disability. Lengths of hospital stays for psychiatric conditions were very similar when comparing the study groups; however, people with developmental disability were more likely to have 2 or more hospitalizations during the year.

CONCLUSIONS

People with developmental disability display unique hospitalization patterns, compared with the general population.

Copy number variations in schizophrenia: critical review and new perspectives on concepts of genetics and disease

OBJECTIVE

Structural variations of DNA, such as copy number variations (CNVs), are recognized to contribute both to normal genomic variability and to risk for human diseases. For example, schizophrenia has an established connection with 22q11.2 deletions. Recent genome-wide studies have provided initial evidence that CNVs at other loci may also be associated with schizophrenia. In this article, the authors provide a brief overview of CNVs, review recent findings related to schizophrenia, outline implications for clinical practice and diagnostic subtyping, and make recommendations for future reports on CNVs to improve interpretation of results.

METHOD

The review included genome-wide surveys of CNVs in schizophrenia that included one or more comparison groups, were published before 2009, and used newer methods. Six studies were identified.

RESULTS

Despite some limitations, these initial genome-wide studies of CNVs provide replicated associations of schizophrenia with rare 1q21.1 and 15q13.3 deletions. Collectively, the results point to a more general mutational mechanism involving rare CNVs that elevate risk for schizophrenia, especially more developmental forms of the disease. Including 22q11.2 deletions, rare risk-associated CNVs appear to account for up to 2% of schizophrenia.

CONCLUSIONS

The more penetrant CNVs have direct implications for clinical practice and diagnostic subtyping. CNVs with lower penetrance promise to contribute to our genetic understanding of pathogenesis. The findings provide insight into a broader neuropsychiatric spectrum for schizophrenia than previously conceived and indicate new directions for genetic studies.

Amygdala volume in a population with special educational needs at high risk of schizophrenia

BACKGROUND

The mildly learning disabled population has a three-fold elevated risk for schizophrenia. It has been proposed that in some individuals this cognitive limitation is a pre-psychotic manifestation of early onset schizophrenia. We examined clinical and neuroanatomical measures of a putative extended phenotype of schizophrenia in an adolescent population receiving special educational assistance. We predicted that people with intellectual impairment and schizotypal features would exhibit amygdala volume reduction as one of the neuroanatomical abnormalities associated with schizophrenia.

METHOD

Assessment by clinical interview, neuropsychological assessment and magnetic resonance imaging scanning was carried out in 28 intellectually impaired individuals identified as being at elevated risk of schizophrenia due to the presence of schizotypal traits, 39 intellectually impaired controls and 29 non-intellectually impaired controls. Amygdala volume was compared in these three groups and the relationship between symptomatology and amygdala volume investigated.

RESULTS

Right amygdala volume was significantly increased in the elevated risk group compared with the intellectually impaired controls (p=0.05). A significant negative correlation was seen between left amygdala volume and severity of negative symptoms within this group (p<0.05), but not in either control group.

CONCLUSIONS

Intellectually impaired subjects judged to be at elevated risk of schizophrenia on the basis of clinical assessment exhibit structural imaging findings which distinguish them from the generality of learning disabled subjects. Within this population reduced amygdala volume may be associated with negative-type symptoms and be part of an extended phenotype that reflects particularly elevated risk and/or early manifestations of the development of psychosis.

Sequence analysis of P21-activated kinase 3 (PAK3) in chronic schizophrenia with cognitive impairment

The P21-activated kinase PAK3 is critical for cognitive development and truncating mutations cause non-syndromic mental retardation (MR). Missense mutations are also associated with psychotic disorders, most commonly with schizophrenia involving premorbid MR, namely "pfropfschizophrenie". We set out to measure the frequency of sequence variants in PAK3 in schizophrenia without premorbid MR. We conducted complete gene reseqeuncing of all coding exons and exon-intron boundaries in patients with schizophrenia with cognitive impairment but without premorbid MR. Deleterious variants in schizophrenia alone were rare (<1/159 or 0.6%). Thereby, while PAK3 remains a strong biological candidate in psychosis, evidence from human genetics provides strongest support for a link to pfropfschizophrenie and not to schizophrenia without premorbid intellectual disability.

Meeting the needs of people with intellectual impairment in primary care

People with intellectual impairments are treated within the mainstream NHS including primary care with little support from specialist services. There are communication issues for primary care staff in relation to access of services and the assessment of health needs for this vulnerable group of individuals. Primary care staff do not always feel equipped to support people with intellectual impairment and need training in order to do so.

Intellectual disability co-occurring with schizophrenia and other psychiatric illness: population-based study

BACKGROUND

The epidemiology of intellectual disability co-occurring with schizophrenia and other psychiatric illness is poorly understood. The separation of mental health from intellectual disability services has led to a serious underestimation of the prevalence of dual diagnosis, with clinicians ill-equipped to treat affected individuals.

AIMS

To estimate the prevalence of dual diagnosis and describe its clinical profile.

METHOD

The Western Australian population-based psychiatric and intellectual disability registers were cross-linked (total n=245,749).

RESULTS

Overall, 31.7% of people with an intellectual disability had a psychiatric disorder; 1.8% of people with a psychiatric illness had an intellectual disability. Schizophrenia, but not bipolar disorder and unipolar depression, was greatly over-represented among individuals with a dual diagnosis: depending on birth cohort, 3.7-5.2% of those with intellectual disability had co-occurring schizophrenia. Pervasive developmental disorder was identified through the Intellectual Disability Register and is therefore limited to individuals with intellectual impairment. None the less, pervasive developmental disorder was more common among people with a dual diagnosis than among individuals with intellectual disability alone. Down syndrome was much less prevalent among individuals with a dual diagnosis despite being the most predominant cause of intellectual disability. Individuals with a dual diagnosis had higher mortality rates and were more disabled than those with psychiatric illness alone.

CONCLUSIONS

The facility to combine records across administrative jurisdictions has enhanced our understanding of the epidemiology of dual diagnosis, its clinical manifestations and aetiological implications. In particular, our results are suggestive of a common pathogenesis in intellectual disability co-occurring with schizophrenia.

Schizotypal cognitions as a predictor of psychopathology in adolescents with mild intellectual impairment

BACKGROUND

There is evidence to suggest that among young people with mild intellectual disability there are those whose cognitive difficulties may predict the subsequent manifestation of a schizophrenic phenotype. It is suggested that they may be detectable by simple means.

AIMS

To gain adequate cooperation from educational services, parents and students so as to recruit a sufficiently large sample to test the above hypothesis, and to examine the hypothesis in the light of the findings.

METHOD

The sample was screened with appropriate instruments, and groups hypothesised as being likely or not likely to have the phenotype were compared in terms of psychopathology and neuropsychology.

RESULTS

Simple screening methods detect a sample whose psychopathological and neuropsychological profile is consistent with an extended phenotype of schizophrenia.

CONCLUSIONS

Difficulties experienced by some young people with mild and borderline intellectual disability are associated with enhanced liability to schizophrenia. Clinical methods can both identify those with this extended phenotype and predict those in whom psychosis will occur.

Learning disabilities within mental health services: are we adequately preparing nurses for the future?

Current government policy dictates that where possible patients who have learning disabilities should be cared for within the framework of ordinary generic national health services, with specialist provision kept to a minimum. The mental health care of this client group may be problematic and diagnostic overshadowing can occur because of complex physical, emotional and behavioural issues. If the government agenda is to be followed, this will have an impact on both the pre- and post-registration education of mental health nurses and therefore this must be addressed by the nursing regulatory bodies. There is also an argument for people who have a learning disability in addition to mental health problems to be considered a specialist group within generic mental health services as are other specific groups because of the complexity of their conditions.

Psychosis and adults with intellectual disabilities. Prevalence, incidence, and related factors

OBJECTIVE

To determine the point prevalence, incidence, and remission over a 2-year period of psychosis in adults with intellectual disabilities, and to investigate demographic and clinical factors hypothesised to be associated with psychosis.

METHOD

A population-based cohort of adults with intellectual disabilities (n = 1,023) was longitudinally studied. Comprehensive face-to-face mental health assessments to detect psychosis, plus review of family physician, psychiatric, and psychology case notes were undertaken at two time points, 2 years apart.

RESULTS

Point prevalence is 2.6% (95% CI = 1.8-3.8%) to 4.4% (95% CI = 3.2-5.8%), dependant upon the diagnostic criteria employed. Two-year incidence is 1.4% (95% CI = 0.6-2.6), and for first episode is 0.5% (95% CI = 0.1-1.3). Compared with the general population, the standardised incidence ratio for first episode psychosis is 10.0 (95% CI = 2.1-29.3). Full remission after 2 years is 14.3%. Visual impairment, previous long-stay hospital residence, smoking, and not having epilepsy were independently associated with psychosis, whereas other factors relevant to the general population were not.

CONCLUSIONS

The study of psychosis in persons with intellectual disabilities benefits the population with intellectual disabilities, and advances the understanding of psychosis for the general population. Mental health professionals need adequate knowledge in order to address the high rates of psychosis in this population.

Pre-frontal lobe gyrification index in schizophrenia, mental retardation and comorbid groups: An automated study

In this paper, we describe the application of an automated method of calculating Gyrification Index (GI) - the Automated GI (A-GI) - to a total of 95 age-matched and sex-matched patients with mental retardation, schizophrenia, comorbid mental retardation and schizophrenia and controls. The results given by the A-GI program show that subjects with mental retardation possessed the lowest GI values in the pre-frontal lobes, with comorbid and schizophrenia groups being midway between this and the controls. The results showed no significant difference in pre-frontal gyrification between the schizophrenia and the comorbid groups. Although the four groups showed a similar pattern of (spatial) differences in terms of pre-frontal lobe volume, this did not solely account for the differences in A-GI. A significant negative correlation between GI and age was also observed across all four groups. These findings suggest that people with schizophrenia have reduced pre-frontal cortical folding regardless of whether or not they have low IQ. Previous studies in the same cohort have suggested that individuals comorbid for schizophrenia and mental retardation may in fact suffer from severe schizophrenia which has led to their low IQ. The pattern of differences observed in the current study supports this view.

Cytogenetic and genetic evidence supports a role for the kainate-type glutamate receptor gene, GRIK4, in schizophrenia and bipolar disorder

In the search for the biological causes of schizophrenia and bipolar disorder, glutamate neurotransmission has emerged as one of a number of candidate processes and pathways where underlying gene deficits may be present. The analysis of chromosomal rearrangements in individuals diagnosed with neuropsychiatric disorders is an established route to candidate gene identification in both Mendelian and complex disorders. Here we describe a set of genes disrupted by, or proximal to, chromosomal breakpoints (2p12, 2q31.3, 2q21.2, 11q23.3 and 11q24.2) in a patient where chronic schizophrenia coexists with mild learning disability (US: mental retardation). Of these disrupted genes, the most promising candidate is a member of the kainate-type ionotropic glutamate receptor family, GRIK4 (KA1). A subsequent systematic case-control association study on GRIK4 assessed its contribution to psychiatric illness in the karyotypically normal population. This identified two discrete regions of disease risk within the GRIK4 locus: three single single nucleotide polymorphism (SNP) markers with a corresponding underlying haplotype associated with susceptibility to schizophrenia (P=0.0005, odds ratio (OR) of 1.453, 95% CI 1.182-1.787) and two single SNP markers and a haplotype associated with a protective effect against bipolar disorder (P=0.0002, OR of 0.624, 95% CI 0.485-0.802). After permutation analysis to correct for multiple testing, schizophrenia and bipolar disorder haplotypes remained significant (P=0.0430, s.e. 0.0064 and P=0.0190, s.e. 0.0043, respectively). We propose that these convergent cytogenetic and genetic findings provide molecular evidence for common aetiologies for different psychiatric conditions and further support the 'glutamate hypothesis' of psychotic illness.

Chromosomal abnormalities and psychosis

The search for susceptibility genes for schizophrenia and severe affective disorder has been enhanced by the study of cytogenetic abnormalities that disrupt genes directly. One such gene is DISCI and there is increasing evidence that it may be an important modulator of risk of psychosis.

Cognitive behaviour therapy and people with learning disabilities: implications for developing nursing practice

People with learning disabilities are an ageing and increasing population and have been the subject of policy initiatives by the four countries of the UK, detailing the range of supports that need to be in place for this group. The evidence base of their mental health needs is growing and with it the need to ensure the full range of psychotherapies available to the general population are made available to people with learning disabilities. Cognitive Behaviour Therapy (CBT) is now a widely accepted and effective form of psychotherapy for many mental health problems and the evidence base is growing on the effectiveness with the learning disability population; however, the model needs to be applied differently for this group to take account of their cognitive impairment and support needs. Registered Nurses in Learning Disabilities are well placed to apply this approach within their clinical practice; however, there is an absence of leadership and direction in the development of CBT for this group of clinicians. There is a need to support education and practice development to contribute to addressing the emotional needs of people with learning disabilities. Action is required to support education to prepare Registered Nurses in Learning Disabilities to practice CBT and to contribute to the ongoing development of research in this area of clinical practice.

Reviewing the use of antipsychotic drugs in people with intellectual disability

INTRODUCTION

Antipsychotics are the most widely prescribed drugs in people with intellectual disability even if schizophrenia and other psychotic disorders do not affect more than 3% of such population. Many authors outline the lack of studies on the efficacy of antipsychotics on schizophrenia or other psychotic disorders in people with intellectual disability.

MATERIALS AND METHODS

The aim of the present study is to review all evidences resulting from international trials selected by Medline, and compare efficacy and side effects of different antipsychotics in people with both intellectual disability and psychotic disorders and/or behavioural disorders.

RESULTS

195 studies were identified; 117 concern traditional antipychotics while 78 new generation ones. If we consider the type of studies, it results that only the 12.8% of all production is represented by meta-analyses, systematic reviews, and randomised and not controlled trials.

CONCLUSIONS

Randomised controlled trials and systematic reviews would be the golden standard for therapeutical studies; unfortunately they are really few in this field. It is anyway significative that all the studies reported focus on the use of antipsychotics in people with intellectual disability presenting behavioural problems. To increase the validity of these studies it is recommendable to proceed only with well-designed studies, possibly double-blind versus placebo or other medications. There is need to define precise inclusion criteria, precise symptomatological or behavioural targets and adaptative ability assessment, using valid and reliable diagnostic instruments.

Empirical comparison of maximal voxel and non-isotropic adjusted cluster extent results in a voxel-based morphometry study of comorbid learning disability with schizophrenia

We present an empirical comparison of cluster extent and maximal voxel results in a voxel-based morphometry (VBM) study of brain structure. The cluster extents are adjusted for underlying deviation from uniform smoothness. We implement this comparison on a four-group cohort that has previously shown evidence of a neuro-developmental component in schizophrenia (Moorhead, T.W.J., Job, D.E., Whalley, H.C., Sanderson, T.L., Johnstone, E.C. and Lawrie, S.M. 2004. Voxel-based morphometry of comorbid schizophrenia and learning disability: analyses in normalized and native spaces using parametric and nonparametric statistical methods. NeuroImage 22: 188-202.). We find that adjusted cluster extent results provide information on the nature of deficits that occur in the schizophrenia affected groups, and these important structural differences are not all shown in maximal voxel results. The maximal voxel and cluster extent results are corrected for multiple comparisons using Random Fields (RF) methods. In order to apply the cluster extent measures, we propose a post-hoc method for determining the primary threshold in the analysis. Unadjusted cluster extent results are reported, for these, no allowance is made for non-isotropic smoothness, and comparison with the adjusted extent results shows that the unadjusted results can be either conservative or anti-conservative depending upon the underlying tissue distributions.

The reliability and validity of general psychotic rating scales with people with mild and moderate intellectual disabilities: an empirical investigation

BACKGROUND

Whilst assessment tools have been developed to diagnose schizophrenia in people with mild intellectual disabilities (IDs), little attention has been paid to developing reliable and valid dimensional measures of psychotic experiences with this population. This study investigates the reliability and validity of two such measures developed for the general adult psychiatric population, the Positive and Negative Syndrome Scale (PANSS) and the Psychotic Symptom Rating Scales (PSYRATS), with a population of adults with mild IDs.

METHOD

Sixty-two adults with mild IDs were interviewed using the PANSS and PSYRATS, and independently interviewed using the Psychiatric Assessment Schedule--Adults with Developmental Disability (PAS-ADD) to obtain psychiatric diagnoses to the criteria of the International Classification of Diseases--Tenth Revision (ICD-10). On the basis of ICD-10 diagnosis, participants were divided into three groups: psychosis (n=11); other mental health problem (n=14); no mental health problem (n=37). PANSS and PSYRATS subscale scores were compared across these three groups and were correlated with PAS-ADD symptom scores across a number of PAS-ADD symptom domains.

RESULTS

All PANSS and PSYRATS subscales showed adequate internal reliability, largely good test-retest reliability, and logical inter-correlations between subscales. The PANSS positive symptoms and the PSYRATS auditory hallucinations subscales differentiated between the psychosis group and the other groups; the PANSS general symptoms subscale differentiated between the psychosis and no mental health problem groups; and the PANSS negative symptoms and the PSYRATS delusions subscales did not differentiate between the three groups.

CONCLUSIONS

The PANSS and PSYRATS are promising measures for use with people with mild IDs and psychotic experiences, although further investigation of items relating to negative symptoms and delusions is warranted.

Pfropfschizophrenia in the age of deinstitutionalization: whose problem?

BACKGROUND

The Kraepelinian concept of pfropfschizophrenia refers to the intertwined coexistence of mental retardation and schizophrenia. Patients with this syndrome are relatively treatment resistant and are often harmed by diverging policies and cost cuts within the framework of mental health care services. Thus, a better understanding of this syndrome has important practical implications. The multiple problems that these patients encounter in various educational and health care agencies and what questions need to be asked to better elucidate these patients' needs are assessed.

DATA

Three case reports of adult long-term inpatients fulfilling the criteria for pfropfschizophrenia are presented. Their current mental status and illness histories are discussed in relation to hypothesized pathophysiological processes and current needs.

LIMITATIONS

Small cohort, naturalistic study.

CONCLUSIONS

Pfropfschizophrenia is a phenotypically heterogeneous syndrome. The chronology of the appearance of cognitive deficits and psychotic symptoms during the course of this disorder should be carefully assessed because it may reflect diverse pathophysiological processes, necessitating differentiated, specific treatment interventions.

Cytogenetics and gene discovery in psychiatric disorders

The disruption of genes by balanced translocations and other rare germline chromosomal abnormalities has played an important part in the discovery of many common Mendelian disorder genes, somatic oncogenes and tumour supressors. A search of published literature has identified 15 genes whose genomic sequences are directly disrupted by translocation breakpoints in individuals with neuropsychiatric illness. In these cases, it is reasonable to hypothesise that haploinsufficiency is a major factor contributing to illness. These findings suggest that the predicted polygenic nature of psychiatric illness may not represent the complete picture; genes of large individual effect appear to exist. Cytogenetic events may provide important insights into neurochemical pathways and cellular processes critical for the development of complex psychiatric phenotypes in the population at large.