Reprint of: Advanced paternal age and risk of schizophrenia in offspring - Review of epidemiological findings and potential mechanisms

A large number of studies have examined the association between advanced paternal age (APA) and risk of schizophrenia in offspring. Here we present an overview of epidemiological studies on this subject published since 2000, and systematically summarize their methodologies and results. Next, we discuss evidence to elucidate the potential mechanisms contributing to the association between APA and offspring schizophrenia, considering paternal psychiatric morbidity and genetic liability, maternal factors, and findings from family design studies. We propose that multiple mechanisms, including causal and non-causal pathways, contribute to the observed relationship between APA and schizophrenia in offspring, and conclude by highlighting the need for multi-disciplinary studies in disentangling these complex, non-mutually exclusive mechanisms.

Evidence of shared familial factors influencing neurocognitive endophenotypes in adult- and childhood-onset schizophrenia

BACKGROUND

The aggregation of neurocognitive deficits among the non-psychotic first-degree relatives of adult- and childhood-onset schizophrenia patients suggests that there may be a common etiology for these deficits in childhood- and adult-onset illness. However, there is considerable heterogeneity in the presentation of neurobiological abnormalities, and whether there are differences in the extent of familial transmission for specific domains of cognitive function has not been systematically addressed.

METHODS

We employed variance components analysis, as implemented in SOLAR-Eclipse, to evaluate the evidence of familial transmission for empirically derived composite scores representing attention, working memory, verbal learning, verbal retention, and memory for faces. We contrast estimates for adult- and childhood-onset schizophrenia families and matched community control pedigrees, and compare our findings to previous reports based on analogous neurocognitive assessments.

RESULTS

We observed varying degrees of familial transmission; attention and working memory yielded comparable, significant estimates for adult-onset and community control pedigrees; verbal learning was significant for childhood-onset and community control pedigrees; and facial memory demonstrated significant familial transmission only for childhood-onset schizophrenia. Model-fitting analyses indicated significant differences in familiality between adult- and childhood-onset schizophrenia for attention, working memory, and verbal learning.

CONCLUSIONS

By comprehensively assessing a wide range of neurocognitive domains in adult- and childhood-onset schizophrenia families, we provide additional support for specific neurocognitive domains as schizophrenia endophenotypes. Whereas comparable estimates of familial transmission for certain dimensions of cognitive functioning support a shared etiology of adult- and childhood-onset neurocognitive function, observed differences may be taken as preliminary evidence of partially divergent multifactorial architectures.

Childhood-Onset Schizophrenia: Insights from Induced Pluripotent Stem Cells

Childhood-onset schizophrenia (COS) is a rare psychiatric disorder characterized by earlier onset, more severe course, and poorer outcome relative to adult-onset schizophrenia (AOS). Even though, clinical, neuroimaging, and genetic studies support that COS is continuous to AOS. Early neurodevelopmental deviations in COS are thought to be significantly mediated through poorly understood genetic risk factors that may also predispose to long-term outcome. In this review, we discuss findings from induced pluripotent stem cells (iPSCs) that allow the generation of disease-relevant cell types from early brain development. Because iPSCs capture each donor's genotype, case/control studies can uncover molecular and cellular underpinnings of COS. Indeed, recent studies identified alterations in neural progenitor and neuronal cell function, comprising dendrites, synapses, electrical activity, glutamate signaling, and miRNA expression. Interestingly, transcriptional signatures of iPSC-derived cells from patients with COS showed concordance with postmortem brain samples from SCZ, indicating that changes in vitro may recapitulate changes from the diseased brain. Considering this progress, we discuss also current caveats from the field of iPSC-based disease modeling and how to proceed from basic studies to improved diagnosis and treatment of COS.

Reduced Functional Brain Activation and Connectivity During a Working Memory Task in Childhood-Onset Schizophrenia

OBJECTIVE

Working memory (WM) deficits are consistently reported in schizophrenia and are related to poor functional outcomes. Functional magnetic resonance imaging studies of adult-onset schizophrenia have reported decreased functional activations and connectivity in the WM network, but no prior functional magnetic resonance imaging study has examined WM in childhood-onset schizophrenia (COS). The aim of this study was to examine the neural correlates of WM in COS.

METHOD

Adult patients with COS (n = 32, 21.3 ± 1.1 years), nonpsychotic siblings of patients with COS (n = 30, 19.4 ± 0.8 years), and healthy controls (n = 39, 20.0 ± 0.7 years) completed 1- and 2-back WM tasks during 3-T functional magnetic resonance imaging. Functional activation and connectivity analyses were conducted. A separate group of 23 younger patients with COS (17.9 ± 7.4 years) could not perform the tasks after twice completing a standard training and are not included in this report.

RESULTS

Patients with COS who were included scored significantly lower than controls on all tasks (p < .001). Patients with COS showed significantly lower activations in the dorsolateral prefrontal cortices, posterior parietal cortices, cerebellum, and caudate and decreased frontoparietal and corticostriatal functional connectivity compared with controls (p < .05, corrected). Siblings had functional activations and connectivity intermediate between those of patients and controls in a similar set of regions (p < .05, corrected). In patients, functional connectivity strength in the left frontoparietal network correlated positively with accuracy scores during the 1-back task (p = .0023, corrected).

CONCLUSION

Decreased functional activation and connectivity in the WM network in COS supports pathophysiologic continuity with adult-onset schizophrenia. The low participation rate and accuracy of the patients highlights the disease severity of COS. Hypo-activations and hypo-connectivity were shared by siblings of patients with COS, suggesting COS as a potential endophenotype.

CLINICAL TRIAL REGISTRATION INFORMATION

Evaluating Genetic Risk Factors for Childhood-Onset Schizophrenia; http://ClinicalTrials.gov;NCT00001198.

[Replicative study of susceptibility to childhood-onset schizophrenia in Kazakhs]

This paper reports the results of replicative analysis of associations of 15 SNPs in a region of 14 genes previously identified in genome-wide association studies (GWAS) with early-onset schizophrenia in Kazakhs. An association of early-onset schizophrenia with genetic markers in three genes (VRK2, KCNB2, and CPVL) was found. An association of rs2312147 in the VRK2 gene with schizophrenia was also previously reported in the Chinese population, so this marker may be considered as possibly race-specific. Two groups consisting of four and six genes demonstrating intergenic epistatic interactions were revealed by multifactor dimensionality reduction methods. The gene ontologies of 14 studied genes were reduced to variants of one molecular function (peptidase activity) and one biological process (positive regulation of biosynthesis processes). Bioinformatic analysis of the protein-protein interactions of products of the genes under study demonstrates that the products of six out of 14 genes may be involved in a single interrelated network, the major connecting link of which is represented by their ubiquitination by the UBC protein.

The genetics of childhood-onset schizophrenia: when madness strikes the prepubescent

Stratification by age at onset has been useful for genetic studies across all of medicine. For the past 20 years, the National Institute of Mental Health has been systematically recruiting patients with onset of schizophrenia before age 13 years. Examination of familial transmission of known candidate risk genes was carried out, and a 10% rate of cytogenetic abnormalities was found. Most recently, high-density, array-based scans for submicroscopic rare copy number variations (CNVs) have suggested that this kind of genetic variation occurs more frequently than expected by chance in childhood-onset schizophrenia (COS) and at a higher rate than observed in adult-onset disorder. Several CNVs and cytogenetic abnormalities associated with COS are also seen in autism and mental retardation. Populations with COS may have more salient genetic influence than adult-onset cases. The relationship of rare CNVs to prepsychotic development is being studied further.

Autism spectrum disorders and childhood-onset schizophrenia: clinical and biological contributions to a relation revisited

OBJECTIVE

To highlight emerging evidence for clinical and biological links between autism/pervasive developmental disorder (PDD) and schizophrenia, with particular attention to childhood-onset schizophrenia (COS).

METHOD

Clinical, demographic, and brain developmental data from the National Institute of Mental Health (and other) COS studies and selected family, imaging, and genetic data from studies of autism, PDD, and schizophrenia were reviewed.

RESULTS

In the two large studies that have examined this systematically, COS is preceded by and comorbid with PDD in 30% to 50% of cases. Epidemiological and family studies find association between the disorders. Both disorders have evidence of accelerated trajectories of anatomic brain development at ages near disorder onset. A growing number of risk genes and/or rare small chromosomal variants (microdeletions or duplications) are shared by schizophrenia and autism.

CONCLUSIONS

Biological risk does not closely follow DSM phenotypes, and core neurobiological processes are likely common for subsets of these two heterogeneous clinical groups. Long-term prospective follow-up of autistic populations and greater diagnostic distinction between schizophrenia spectrum and autism spectrum disorders in adult relatives are needed.

Sequencing and Analyzing the t(1;7) Reciprocal Translocation Breakpoints Associated with a Case of Childhood-onset Schizophrenia/Autistic Disorder

We characterized a t(1;7)(p22;q21) reciprocal translocation in a patient with childhood-onset schizophrenia (COS) and autism using genome mapping and sequencing methods. Based on genomic maps of human chromosome 7 and fluorescence in situ hybridization (FISH) studies, we delimited the region of 7q21 harboring the translocation breakpoint to a approximately 16-kb interval. A cosmid containing the translocation-associated 1:7 junction on der(1) was isolated and sequenced, revealing the positions on chromosomes 1 and 7, respectively, where the translocation occurred. PCR-based studies enabled the isolation and sequencing of the reciprocal 7:1 junction on der(7). No currently recognized gene on either chromosome appears to be disrupted by the translocation. We further found no evidence for copy-number differences in the genomic regions flanking the translocation junctions in the patient. Our efforts provide sequence-based information about a schizophrenia/autism-associated translocation, and may facilitate future studies investigating the genetic bases of these disorders.

Schizophrenic-like neurocognitive deficits in children and adolescents with 22q11 deletion syndrome

22q11.2 Deletion Syndrome (22q11DS) is the most common genetic microdeletion syndrome affecting humans. The syndrome is associated with general cognitive impairments and specific deficits in visual-spatial ability, non-verbal reasoning, and planning skills. 22q11DS is also associated with behavioral and psychiatric abnormalities, including a markedly elevated risk for schizophrenia. Research findings indicate that people with schizophrenia, as well as those identified as schizoptypic, show specific cognitive deficits in the areas of sustained attention, executive functioning, and verbal working memory. The present study examined such schizophrenic-like cognitive deficits in children and adolescents with 22q11DS (n = 26) and controls (n = 25) using a cross-sectional design. As hypothesized, 22q11DS participants exhibited deficits in intelligence, achievement, sustained attention, executive functioning, and verbal working memory compared to controls. Furthermore, deficits in attention and executive functioning were more pronounced in the 22q11DS sample relative to general cognitive impairment. These findings suggest that the same pattern of neuropsychological impairment seen in patients with schizophrenia is present in non-psychotic children identified as at-risk for the development of schizophrenia based on a known genetic risk marker.

Sleep disturbances in childhood-onset schizophrenia

Sleep disturbances in psychiatric disease have long been reported. However, research on sleep disturbances in child and adolescent psychiatric disorders is limited. We examined the relationship of sleep disturbance to clinical severity and co-morbid diagnoses (e.g. anxiety), for a population with childhood-onset schizophrenia (COS). Sixty-one COS patients underwent a medication-free inpatient observation period as part of an NIMH study of COS. Sleep quantity during the last 5-7 days of a patient's medication-free period was measured using safety records and daily nursing notes. Subjects were divided into two groups: "good sleepers" (>6 h) and "poor sleepers" (<6 h) based on the average of total hours slept per night. Comparisons between groups were made with respect to clinical ratings at both admission and during washout period, co-morbid diagnosis of generalized anxiety disorder (GAD) and a susceptibility gene (G72) for COS. The median average sleep score for the entire group was 6.1 (S.D.=2.01) h. The good and poor sleep groups differed significantly in terms of severity of positive symptoms (SAPS) and negative symptoms at admission (SANS) both on admission and during the medication-free period. There was no significant relationship between G72 genotypes and a past and/or present diagnosis of GAD. COS patients suffer from significant sleep disturbances and the sleep disturbance is highly related to the symptom severity. As there are numerous health implications of poor sleep, clinicians should have a low threshold for treating sleep disturbances in this population.

Segmental uniparental isodisomy on 5q32-qter in a patient with childhood-onset schizophrenia

Schizophrenia is a severe mental disorder affecting approximately 1% of the world's population. Although the aetiology of schizophrenia is complex and multifactorial, with estimated heritabilities as high as 80%, genetic factors are the most compelling. Childhood-onset schizophrenia (COS), defined as onset of schizophrenia before the age of 13 years, is a rare and malignant form of the illness that may have more salient genetic influence. The first known case of paternal segmental uniparental isodisomy (iUPD) on 5q32-qter in a patient with COS is described, which adds to the previously known high rates of chromosomal abnormalities reported in this sample. iUPD is a rare genetic condition in which the offspring receives two chromosomal homologues from one parent. Segmental UPD is defined as UPD on a portion of a chromosome with biparental inheritance seen in the rest of the homologous pair. Complications owing to this abnormality may arise from malfunctioning imprinted genes or homozygosity of recessive disease-causing mutations. This aberration became apparent during whole-genomic screening of a COS cohort and is of particular interest because 5q has been implicated in schizophrenia by several genomewide linkage studies and positive gene associations. This report, therefore, presents more evidence that schizophrenia susceptibility gene, or genes, may be found on distal 5q.

Abnormal infant neurodevelopment predicts schizophrenia spectrum disorders

OBJECTIVE

The aim of this study was to detect infants who carry a schizophrenic genotype and study the development of schizophrenia spectrum disorders (SZSD) from birth.

INTRODUCTION

In the 1940s, Bender described uneven maturation in childhood schizophrenics and in 1952 found this in the infant histories of 6 schizophrenic children.

METHODS

We tested a possible index for defective neural integration in infants termed "pandysmaturation" (PDM). This required retarded cranial growth plus retarded and erratic gross motor development on a single exam. Twelve offspring of hospitalized schizophrenic mothers and 12 infants in a "Well Baby Clinic," were examined 10 times between birth and 2 years of age. Psychiatric interviews and psychological testing were done at 10, 15, and 22 years of age, plus follow-up at 27-35 years of age.

RESULTS

Six infants had PDM at 2, 6, or 13 months of age. Five individuals have been blindly diagnosed (by KSK) as having lifetime SZSD; all 5 had PDM before 8 months. Chi-square one-tailed tests confirmed the predictions: (1) PDM was related to subsequent SZSD (chi(2) = 11.43; p < 0.0005); (2) schizophrenic mothers had more infants with PDM than nonschizophrenic mothers (chi(2) = 3.28; p < 0.05); and (3) schizophrenic mothers had more SZSD offspring than nonschizophrenic mothers (chi(2) = 6.39; p < 0.0125).

DISCUSSION

These first behavioral observations of aberrant neurodevelopment in pre- SZSD infants support the evidence of early neurodevelopmental disorder seen in studies of brain pathology in SZSD adults.

Childhood-onset schizophrenia: smooth pursuit eye-tracking dysfunction in family members

BACKGROUND

Childhood-onset schizophrenia (COS), a severe form of the disorder, is of interest for etiologic studies. Smooth pursuit eye-tracking dysfunction (ETD) is a biological marker for schizophrenia.

AIMS

To compare familial eye-tracking abnormalities for COS and adult-onset schizophrenia (AOS).

METHOD

Eye-tracking performance for 70 COS parents, 64 AOS parents and 20 COS siblings was compared to their respective age-matched control groups.

RESULTS

COS and AOS parents had higher rate of dichotomously rated eye-tracking dysfunction than their respective controls (16% vs. 1% and 22% vs. 4%, respectively). COS parents and siblings also differed from controls on several continuous measures. However, scores for COS, AOS and control groups overlapped extensively.

CONCLUSIONS

Genetic factors underlying eye-tracking dysfunction appear more salient for COS. However, eye-tracking measures have to be used with caution for endophenotypic definition due to low predictive power.

DECLARATION OF INTEREST

The study was done at the National Institutes of Health.

Childhood onset schizophrenia: familial neurocognitive measures

OBJECTIVE

Early onset disorders may have more salient familial/genetic etiology. Neurocognitive deficits which are seen in families of adult onset schizophrenic patients were examined in healthy family members of patients with childhood-onset schizophrenia (COS).

METHODS

Trail Making Tests (TMT) A and B, Wechsler Intelligence Scale-Revised Digit Span and Vocabulary subtests were administered to 67 parents and 24 siblings of patients with childhood-onset schizophrenia and 114 healthy community controls (CC) comparable in sex, age, and educational level.

RESULTS

COS siblings performed significantly more poorly than did controls on Trails Making Test B with a trend for poorer performance evident on Trails Making Test A. COS parents performed more poorly than controls only on Trails Making Test A.

CONCLUSIONS

Healthy first-degree relatives of COS probands have subtle deficits in tests involving oculomotor/psychomotor speed, working memory and executive function. This provides further support for continuity between COS and later onset schizophrenia and for a familial/genetic factor associated with the illness.

Polymorphisms in the 13q33.2 gene G72/G30 are associated with childhood-onset schizophrenia and psychosis not otherwise specified

BACKGROUND

Childhood-onset schizophrenia (COS), defined as onset of psychotic symptoms by age 12 years, is a rare and severe form of the disorder that seems to be clinically and neurobiologically continuous with the adult disorder.

METHODS

We studied a rare cohort consisting of 98 probands; 71 of these probands received a DSM-defined diagnosis of schizophrenia, and the remaining 27 were diagnosed as psychosis not otherwise specified (NOS) (upon 2-6 year follow-up, 13 have subsequently developed bipolar disorder). Two overlapping genes, G72 and G30 on 13q33.2, were identified through linkage-disequilibrium-based positional cloning. Single nucleotide polymorphisms (SNPs) at the G72/G30 locus were independently associated with both bipolar illness and schizophrenia. We analyzed SNPs at this locus with a family-based transmission disequilibrium test (TDT) and haplotype analyses for the discrete trait, as well as quantitative TDT for intermediate phenotypes, using the 88 probands (including COS and psychosis-NOS) with parental participation.

RESULTS

We observed significant pairwise and haplotype associations between SNPs at the G72/G30 locus and psychotic illness. Furthermore, these markers showed associations with scores on a premorbid phenotype measured by the Autism Screening Questionnaire, and with age of onset.

CONCLUSIONS

These findings, although limited by potential referral bias, confirm and strengthen previous reports that G72/G30 is a susceptibility locus both for schizophrenia and bipolar disorder.

Neurocognitive impairments in nonpsychotic parents of children with schizophrenia and attention-deficit/hyperactivity disorder: the University of California, Los Angeles Family Study

BACKGROUND

We tested the hypotheses that certain neurocognitive impairments index genetic liability to schizophrenia and that childhood-onset schizophrenia (COS) is a variant of adult-onset schizophrenia (AOS) by determining whether parents of COS probands show the types of neurocognitive impairments found in relatives of AOS probands.

METHODS

Parents of COS probands (n = 79) were compared with parents of attention-deficit/hyperactivity disorder (ADHD; n = 190) and community control (CC; n = 115) probands on 3 neurocognitive tasks shown in previous research to detect impairments in patients with AOS and ADHD and in the relatives of patients with AOS. Parents with a diagnosis of psychosis were excluded from the study.

RESULTS

On the Degraded Stimulus-Continuous Performance Test and the Trail-Making Test B-Adolescent Version, the parents of COS probands performed significantly worse than the parents of CC and ADHD probands, who did not differ significantly from each other. On the Span of Apprehension, we found no significant group differences. Using rigorous cutoffs, a combination of scores on the 3 neurocognitive tests identified 16 (20%) of the mothers and fathers of COS probands compared with 0% of the mothers and fathers of CC probands. There was diagnostic specificity of the neurocognitive impairments. A combination of neurocognitive scores identified 6 (12%) of the mothers of COS probands vs 0% of the mothers of ADHD probands. A cutoff that identified 2 (2%) of the fathers of ADHD probands classified 5 (17%) of the fathers of COS probands. We found no significant differences in neurocognitive functions between the parents of ADHD and CC probands.

CONCLUSIONS

The aggregation of neurocognitive impairments in the parents of COS probands provides further evidence of etiologic continuity between COS and AOS. A substantial subgroup of parents of COS probands had a worse neurocognitive performance than that of any of the parents of ADHD and CC probands. Receiver operating characteristic curves showed that when rigorous cutoffs define neurocognitive impairments, the combination of scores on certain neurocognitive tasks produced a level of diagnostic accuracy in the parents of COS probands that is sufficient for use in genetic linkage studies.

Childhood-onset schizophrenia: research update

This review is a research update of recent literature related to childhood-onset schizophrenia (onset of psychotic symptoms by age 12 years). This subgroup of patients has attracted considerable research interest because patients with a childhood onset may represent a more homogeneous patient population in which to search for risk or etiologic factors. We examine data indicating that childhood-onset schizophrenia (COS) shares the same clinical and neurobiologic features as later-onset forms of the disorder. Compared with adults with schizophrenia, however, this subgroup of patients appears to have more severe premorbid neuro-developmental abnormalities, more cytogenetic anomalies, and potentially greater family histories of schizophrenia and associated spectrum disorders. While preliminary, these data indicate that a greater genetic vulnerability may be one of the underpinnings of COS. Future studies of this subgroup may provide important clues as to the genetic basis for schizophrenia and how gene products influence certain features of the disease, such as age of onset and mode of inheritance.

Smooth pursuit eye-tracking impairment in childhood-onset psychotic disorders

OBJECTIVE

Although childhood-onset schizophrenia is relatively rare, a sizable group of children with severe emotional disturbances have transient psychotic symptoms that fall outside of current syndrome boundaries. The relationship of this group of children to those with childhood-onset schizophrenia and other childhood psychiatric disorders is unclear. In this study, the authors compared smooth pursuit eye tracking, a biological trait marker associated with schizophrenia, of children and adolescents with psychotic disorder not otherwise specified to that of children with childhood-onset schizophrenia and healthy comparison subjects.

METHOD

By means of infrared oculography, smooth pursuit eye movements during a 17 degrees /second visual pursuit task were quantitatively and qualitatively compared in 55 young adolescents (29 with childhood-onset schizophrenia and 26 with psychotic disorder not otherwise specified) and their respective independent healthy comparison groups (a total of 38 healthy subjects).

RESULTS

Subjects with childhood-onset schizophrenia had qualitatively poorer eye tracking, higher root mean square error, lower gain, and a greater frequency of catch-up saccades than healthy children. Subjects with psychotic disorder not otherwise specified also had qualitatively poorer eye tracking, higher root mean square error, and lower gain than healthy children, but saccade frequency did not differ significantly.

CONCLUSIONS

Children with childhood-onset schizophrenia exhibit a pattern of eye-tracking dysfunction similar to that reported for adult patients. Similar abnormalities were seen in the subjects with psychotic disorder not otherwise specified except that they did not exhibit a greater frequency of catch-up saccades. Prospective longitudinal neurobiological and clinical follow-up studies of both groups are currently underway to further validate the distinction between these two disorders. Also, family studies are planned to establish whether eye-tracking dysfunction represents a trait- or state-related phenomenon in subjects with psychotic disorder not otherwise specified.

Cognitive brain potentials in children at risk for schizophrenia: preliminary findings

Event-related brain potentials were recorded to auditory stimuli from children at risk for schizophrenia and normal control children who were part of two independent samples being followed longitudinally. Subjects were required to detect (with a reaction time response) one of two infrequent events (either a pitch change or a missing stimulus), each of which occurred 17 percent of the time, and was embedded in a sequence of frequent events occurring 66 percent of the time. The event-related potential (ERP) elicited by both infrequent stimuli consisted of a positive-going wave peaking at 350 msec for the pitch change ERP (P350) and 400 msec for the missing stimulus ERP (P400) and a slow wave, which overlapped with and extended beyond the P350 and P400 potentials. When the eliciting event was relevant, these potentials were significantly larger than when it was irrelevant. When the waveforms by the highrisk (HR) subjects were compared to those produced by the normal control (NC) subjects, the HR subjects of both samples showed significantly less late positive amplitude (P350 and P400) than the NC subjects, but only when the eliciting event was relevant. This effect appeared to be independent of reaction time, as reaction time means and variances were quite similar between risk groups. Other possible explanations for this amplitude reduction were explored. Since late positive component amplitude reduction has been consistently reported to characterize the waveforms of adult schizophrenics, the reduction seen in children at genetic risk for schizophrenia may be a premorbid indicator for the development of the psychosis.

The diagnosis and treatment of children and adolescents with schizophrenia. "My mind is playing tricks on me"

This article discusses the clinical phenomenology, natural history, neurobiologic features, diagnostic and medical assessment, and management of schizophrenia, and also details pharmacologic treatments.

Velocardiofacial syndrome in childhood-onset schizophrenia

OBJECTIVES

Deletion of chromosome 22q11 (velocardiofacial syndrome) is associated with early neurodevelopmental abnormalities and with schizophrenia in adults. The rate of 22q11 deletions was examined in a series of patients with childhood-onset schizophrenia (COS), in whom early premorbid developmental and cognitive impairments are more pronounced than in adult-onset cases.

METHOD

Through extensive recruiting and screening, a cohort of 47 patients was enrolled in a comprehensive study of very-early-onset schizophrenia. All were tested with fluorescence in situ hybridization for deletions on chromosome 22q11.

RESULTS

Three (6.4%) of 47 patients were found to have a 22q11 deletion. All 3 COS patients with 22q11 deletions had premorbid impairments of language, motor, and social development, although their physical characteristics varied. Brain magnetic resonance imaging revealed increased midbody corpus callosum area and ventricular volume in relation both to healthy controls and to other COS patients.

CONCLUSIONS

The rate of 22q11 deletions in COS is higher than in the general population (0.025%, p < .001) and may be higher than reported for adult-onset schizophrenia (2.0%, p = .09). These results suggest that 22q11 deletions may be associated with an earlier age of onset of schizophrenia, possibly mediated by a more salient neurodevelopmental disruption.

Continuous-processing related ERPS in adult schizophrenia: continuity with childhood onset schizophrenia

BACKGROUND

Previous work with schizophrenic children disclosed deficits on two continuous performance tests (CPTs) and ERP indices of reduced attentional resource allocation.

METHODS

The two CPTs were administered to adult schizophrenics and matched control subjects. The simple CPT required only that the subject respond whenever the target digit was displayed. The complex version required a response whenever any digit was displayed on two successive trials. Event-related potentials (ERPs) were recorded during task performance.

RESULTS

Schizophrenics had fewer hits on both CPT versions, showed a greater drop in performance from the simple to the complex CPT, and took longer to respond than controls. The processing negativity (Np) showed a greater amplitude increase from nontarget to target in normals than in schizophrenics, and the overlapping P2 component was more negative in normals. P3 latency was longer in schizophrenics, but P3 amplitude did not differ.

CONCLUSIONS

Group performance and processing negativity effects replicated those from an earlier study of schizophrenic and normal children administered the same versions of the CPT, suggesting similar abnormalities in the allocation and modulation of information processing resources.

Evidence for bilineal inheritance of physiological indicators of risk in childhood-onset schizophrenia

Childhood-onset schizophrenia is proposed to be associated with increased genetic loading compared with adult-onset schizophrenia because of its earlier age of onset and generally greater severity of symptoms. Diminished suppression of P50 auditory evoked responses to repeated stimuli and elevated anticipatory saccades during smooth pursuit eye movements are markers of genetic risk that are found in members of families with schizophrenia even in the absence of the full clinical disorder and appear to be transmitted in a single gene autosomal dominant fashion. Adult-onset schizophrenia is generally associated with one parent who demonstrates abnormal P50 sensory gating and elevated anticipatory saccades and one parent who is normal on the physiologic measures (i.e., unilineal inheritance). This study investigates whether childhood-onset schizophrenia is similarly unilineal or is associated with the inheritance of genetic risk factors from both parents (i.e., bilineal inheritance). Ten childhood-onset schizophrenic probands and their parents were studied. Their P50 sensory gating and anticipatory saccades were compared with adult-onset schizophrenic probands and their parents. Bilineality, measured as physiological impairment in both parents, occurred more frequently in childhood-onset probands than in adult-onset probands for both P50 sensory gating deficits (60% versus 13%) and elevated anticipatory saccades (60 versus 0%). Additionally, childhood-onset schizophrenic probands performed more poorly than adult-onset probands on the anticipatory saccade measure. This physiological evidence suggests that childhood-onset schizophrenia may be associated with increased genetic loading because of contributions of genetic risk from both parents.

Brief report: association of sex chromosome anomalies with childhood-onset psychotic disorders

OBJECTIVE

An apparent excess of sex chromosome aneuploidies (XXY, XXX, and possibly XYY) has been reported in patients with adult-onset schizophrenia and with unspecified psychoses. This study describes the results of cytogenetic screening carried out for pediatric patients meeting DMS-III-R criteria for childhood-onset schizophrenia (COS) and a subgroup of patients with childhood-onset psychotic disorder not otherwise specified, provisionally labeled by the authors as multidimensionally impaired (MDI).

METHOD

From August 1990 to July 1997, karyotypes were determined for 66 neuroleptic-nonresponsive pediatric patients (28 MDI, 38 COS), referred to the National Institute of Mental Health for an inpatient treatment trial of clozapine.

RESULTS

Four (6.1%) of 66 patients (3 MDI, 1 COS) were found to have sex chromosome anomalies (mosaic 47,XXY; 47,XXY; 47,XYY; mosaic 45,XO, respectively), which is higher than the expected rate of 1 per 426 children or 2.34 per 1,000 in the general population (4/66 versus 1/426, chi 2 = 19.2, df = 1, p = .00001). All cases had been previously undiagnosed.

CONCLUSIONS

These findings lend support to a hypothesis that a loss of balance of gene products on the sex chromosomes may predispose affected individuals to susceptibility to additional genetic and environmental insults that result in childhood-onset psychotic disorders. Karyotyping of children with psychotic disorders should be routine.

[Diagnostic and follow-up typological characteristics of early schizophrenia]

Schizophrenic psychoses with early onset (< or = 10) are very rare; they occur in approx. 0.5-1% of the total number of patients. Long-term research with sufficiently long observation periods may be able to answer the question whether there is a nosological continuity between early-onset schizophrenia and schizophrenic psychoses in adults. We report on the results of a study on 13 patients with onset at the age of 10 years or earlier (7 girls, 6 boys) with an average duration of illness of 36.1 years (SD = 10.2 years). 3 patients had deceased in the meantime, one patient could not be reached by mail. 9 of the original 13 patients could be examined during the second follow-up by the same interviewer (on the average 27 years after the first follow-up). In 5 children the onset was acute (less than one week), in 8 children insidious (more than 4 weeks). Among the 5 patients with acute onset of childhood psychoses the positive PANSS-type (60%) predominated, in the 8 patients with at first barely perceptible beginning, the negative PANSS-type (45%) prevailed. In respect of the diagnostic division into subcategories, we found a remarkably large variability: At the beginning the disorganised type, at the first follow-up the paranoid, and at the second follow-up the catatonic and the disorganised type were diagnosed most frequently by 4 independent raters. The evaluation of the whole course shows that the incidence of the paranoid type was most frequent. Clear positive-productive psychotic symptoms occurred very early in our patients, i.e. already at the age of 7 years. On the whole, 77% of the patients showed positive symptoms from the beginning of psychotic breakdown; more than half of them had hallucinations from the beginning. This is contrary of the current opinion that childhood-onset schizophrenia begins predominantly with negative symptoms. However, at the beginning of insidious courses, negative symptoms prevail. The prognosis for the 8 insidious courses on the whole was unfavourable (only one full remission, one partial remission, the rest poor or very poor remissions). No connection between the total diagnosis (subtype) and the remission grade was seen.

The neurodevelopmental theory of schizophrenia: evidence concerning structure and neuropsychology

Severe schizophrenics as a group show subtle abnormalities of cerebral structure. Cerebral ventricular enlargement is the best replicated finding, and this tends to be associated with impairment of neuropsychological performance. The idea that these abnormalities have a neurodevelopmental origin gains indirect support from the, admittedly less consistent, evidence of abnormalities of cerebral asymmetry and of neuronal migration in adult schizophrenics, as well as from the better established behavioural, psychomotor, and cognitive impairments reported in preschizophrenic children. However, the relationship between childhood and adult neuropsychological and brain structural findings has not been proven, and we don not know whether only some schizophrenia has a developmental origin, or whether patients differ only in the degree of developmental impairment that they show.

Clinical features of childhood-onset schizophrenia with obsessive-compulsive symptoms during the prodromal phase

Thirty-nine patients with schizophrenia, diagnosed according to DSM-III-R, who were under 15 years of age, were studied in two groups; 16 subjects with obsessive-compulsive symptoms during the prodromal phase, and 23 with no obsessive-compulsive disorders. The group with obsessive-compulsive symptoms during the prodromal phase was characterized by a higher ratio of males, higher incidences of perinatal and brain computed tomography (CT) abnormalities, fewer hereditary factors, longer duration of the prodromal phase, and a higher incidence of insidious onset and negative symptoms compared with the group without such prodromal symptoms. Schizophrenic patients with obsessive-compulsive symptoms during the prodromal phase were clinically distinct from those without, which suggests the possibility of subtype categorization.

Practice parameters for the assessment and treatment of children and adolescents with schizophrenia. American Academy of Child and Adolescent Psychiatry

These practice parameters review the literature on children and adolescents with schizophrenia. Because this literature is sparse, information is also drawn from research with adults. Clinical features in youth with schizophrenia include predominance in males, high rate of premorbid abnormalities, increased family history of schizophrenia, and often poor outcome. Diagnostic issues include the overlap, and therefore potential for misdiagnosis, between the first presenting symptoms of schizophrenia and those of psychotic mood disorders, developmental disorders, organic conditions, and other nonpsychotic emotional/behavioral disorders. Treatment should include using antipsychotic medications in conjunction with psychoeducational, psychotherapeutic, and social and educational support programs.

Clozapine treatment in very early onset schizophrenia

Very early onset schizophrenic patients only partially benefit from conventional antipsychotic treatment and are at increased risk for developing tardive dyskinesia (TD). Clozapine, which lacks extrapyramidal side effects including TD, has been proved effective for adult schizophrenic patients who are resistant to other neuroleptics. Clozapine, therefore, may offer an alternative treatment for these patients. The authors report four successful trials of clozapine in children aged 10 to 12 years old with schizophrenia, the youngest group reported on to date, who were unresponsive to conventional neuroleptic treatment.

[Early onset schizophrenia (case report)]

A total of 120 children and adolescents with the diagnosis of schizophrenia were hospitalized at the psychiatric clinic in Prague in 1946-1975. Of the 120 patients (58% males and 42% females) 12.5%, i.e. 15 died by 1988. The results are consistent with data in the literature which pertain to pregnancy, family background, relations with people already before the disease developed, social maladaptation, more frequent loss of a parent, depressive symptoms at the onset of the disease, changes on the EEG and neurological examination. The results differ as regards--1. A much greater hereditary load in grade II relatives 45% (19% psychoses, 14% suicides, 12% alcoholism). 2. A greater hereditary load in grade I relatives-parents and siblings (16% psychoses and suicides, 5% alcoholism, 12% personality disorders). 3. The authors detected more psychoses among grade I relatives 14% (11% schizophrenia, 3% manic-depressive psychosis). The hereditary load in the narrower sense of the word in grade I relatives is significantly elevated 16% (14.5% psychoses, 1.5% suicides). Based on the results pertaining to the 15-42-year catamnestic investigation of education, occupation, attempts to work, a certain socialization, attacks and remissions, the authors elaborated the prognosis. The author's prognosis of early onset schizophrenia: 10% complete cure, 17% remission alternating with relapses, 73% chronic patients (20% are capable of a certain socialization; in 53% permanent care by another person is necessary-this applies to chronic patients with a defect-deterioratio and postpsychotic psychopathization.

Schizophrenia in children: a review of European research

European literature on childhood schizophrenia is divergent and vast. The topic itself is controversial and complex. The article reviews selected European literature on childhood schizophrenia and presents the most important trends of research from the literature. Extensive work has been devoted in tracing and defining the boundaries of childhood schizophrenia from infantile psychosis, autism, organic psychoses, and borderline states, and of mapping out the condition. The factor of development as an important variable when studying diagnostic criteria and the course of the condition was singled out by many researchers. The evidence from the research on etiological factors was also reviewed, and most authors seem to agree on a nature-nurture interaction model. The different treatment modalities and approaches are also presented and discussed. Finally, a proposal is made for comparative studies to be carried out that will cover course and followup.

Childhood schizophrenia. A review and comparison with adult-onset schizophrenia

Childhood schizophrenia versus childhood autism and the phenomenology, epidemiology, and premorbid characteristics of childhood schizophrenia are reviewed, as well as pregnancy and birth complications, electroencephalographic studies, biochemistry, and genetic factors of this disorder. Treatment considerations and follow-up studies are outlined.

Symptomatic thyroiditis and schizophrenia in a six-year-old girl

A case of simultaneous symptomatic thyroiditis and schizophrenia in a prepubertal child is reported. The coexistence of these disorders has implications for potential diagnostic confusion and raises speculation of a shared immunologic and/or genetic etiology.

Infantile autism and childhood schizophrenia: review of the issues from the sociocultural point of view

After presenting an historical overview of the development of the concept of childhood psychosis, this paper discusses the various etiologies which have been offered to explain severe disturbances of childhood. Reference is made to the nature/nurture polemic. In spite of the general belief that the etiology is biologically determined, particularly in infantile autism, the actual evidence tends to be meagre. Furthermore, the literature includes a number of studies which have been found to be methodically weak and which seem to disclaim the intellectual and socioeconomic superiority of the parents of autistic children, contrary to Kanner's original finding that such superiority exists. The link between social class and autism, according to Cantwell's review, does not appear to fit a purely biological causation of autism. This remains an awkward finding which still demands an explanation. The contention of this paper is that contradictory findings could be explained, as stated by Kanner, by the 'inordinate' use of the label 'autism' to include various types of children's severe disorders, even brain-damaged children. Furthermore this review emphasizes the fact that a total neglect of sociocultural variables in the study of such children has led to confounding results. A careful reading of the literature and correspondence with numerous psychiatrists around the world have led the author to believe that infantile autism is more prevalent in highly technological countries where there is extensive geographical and economic mobility coupled with the nuclearization of the family. This paper offers supportive evidence for this speculation.

Children at risk for schizophrenia. Clinical and attentional characteristics

Adolescent high-risk subjects, offspring of schizophrenic mothers, who were placed in foster homes at an early age, are compared with foster children whose biological parents have no record of psychiatric hospitalization and with non-foster children. The high-risk group showed increased social isolation, difficulties in the student role, elevated total symptom scores on the Psychiatric Status Schedule, and elevated schizophrenic scale scores on the Minnesota Multiphasic Personality Inventory. Half of the high-risk subjects showed significant impairment on a battery of eight attention-demanding tasks.

Children at risk for schizophrenia

Etiological factors in the transmission of schizophrenia are reviewed; models include psychogenic, genetic, gene/environment interaction. Investigation of premorbid history is discussed employing retrospective, follow-back, follow-up, and prospective studies. Certain symptom clusters (attentional and cognitive deficits, poor socialization, withdrawal) in genetically predisposed individuals may predict schizophrenia. Stress-reducing therapeutic environments are proposed.

The families of borderlines. A comparative study

The families of 12 carefully diagnosed patients with borderline personality disorder are compared with the families of both paranoid schizophrenic patients and patients with neurotic personality disorders. The families of the borderline patients were distinguished by the rigid tightness of the marital bond to the exclusion of the attention, support, or protection of the children. This pattern of neglect conforms to one theme in the clinical literature, and its implications for understanding and treating borderline patients are discussed. Limitations in the research methodology make the conclusions from this study tentative, but the results suggest new areas in need of research attention.

Offspring of schizophrenics. III. Hyperactivity and neurological soft signs

Twenty-nine male offspring of "continuous schizophrenics" (chronic, borderline, and chronic schizoaffective schizophrenics), plus controls, were given neurological and psychological examinations at age 7. Eight of the 29 were found to have high ratings on a factor score that was termed "hyperactive" (increased activity, impulsivity, distractibility, and emotional lability), and three of these boys had high ratings for neurological signs as well. These frequencies were significantly greater than the control values. Mild incoordination, such as awkwardness in performing rapidly alternating movements, was the neurological soft sign most elevated in the index group. Fifteen female offspring of schizophrenics were not found to differ from their controls on these measures. Previous studies of the childhood of male schizophrenics have found behavior patterns similar to the behavior of the boys who scored high on our hyperactive factors. It is thus likely that the "hyperactive cases" in this sample are even more at risk for developing schizophrenia in later life than the other offspring of schizophrenic parents.

Egocentrism in children of parents with a history of psychotic disorders

It is known that children of schizophrenic parents have an increased risk for becoming schizophrenic, but it has been extremely difficult to determine what features may exist in such children before they become manifestly ill that might provide a key for identifying vulnerability to subsequent disorder. This study was carried out to determine whether certain types of egocentric perception exist in the children of psychotic parents that might represent a clue to vulnerability. Sixty parent-child pairs were investigated as part of the University of Rochester (NY) Child and Family Study, using standardized diagnostic assessment procedures in the parents and several methods for evaluating egocentric perception in their offspring. Results showed that severity of psychotic symptoms in a parent related significantly to the degree of persistent age-inappropriate spatial egocentrism in his or her child. All of several diagnostic approaches used for parent classification were about equally valid in this regard, except for hospital diagnosis of schizophrenia, which did not correlate significantly with offspring egocentricity.

Minor physical anomalies in young psychotic children

The authors examined three groups of children for minor physical anomalies: 52 autistic children, 34 nonautistic siblings of these patients, and 29 normal controls. The total number of anomalies and the weighted score were significantly higher in the autistic children. The formation of these anomalies in the first three months of fetal life may concur with the developmental deviation of the central nervous system in some of these individuals.