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.

Hippocampal volume change relates to clinical outcome in childhood-onset schizophrenia

BACKGROUND

Fixed hippocampal volume reductions and shape abnormalities are established findings in schizophrenia, but the relationship between hippocampal volume change and clinical outcome has been relatively unexplored in schizophrenia and other psychotic disorders. In light of recent findings correlating hippocampal volume change and clinical outcome in first-episode psychotic adults, we hypothesized that fewer decreases in hippocampal volume would be associated with better functional outcome and fewer psychotic symptoms in our rare and chronically ill population of childhood-onset schizophrenia (COS) patients.

METHOD

We prospectively obtained 114 structural brain magnetic resonance images (MRIs) from 27 COS subjects, each with three or more scans between the ages of 10 and 30 years. Change in hippocampal volume, measured by fit slope and percentage change, was regressed against clinical ratings (Children's Global Assessment Scale, Scale for the Assessment of Positive Symptoms, Scale for the Assessment of Negative Symptoms) at last scan (controlling for sex, time between scans and total intracranial volume).

RESULTS

Fewer negative symptoms were associated with less hippocampal volume decrease (fit slope: p = 0.0003, and percentage change: p = 0.005) while positive symptoms were not related to hippocampal change. There was also a relationship between improved clinical global functioning and maintained hippocampal volumes (fit slope: p = 0.025, and percentage change: p = 0.043).

CONCLUSIONS

These results suggest that abnormal hippocampal development in schizophrenia can be linked to global functioning and negative symptoms. The hippocampus can be considered a potential treatment target for future therapies.

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.

Cortical brain development in schizophrenia: insights from neuroimaging studies in childhood-onset schizophrenia

Childhood-onset schizophrenia (COS; defined as onset by age 12 years) is rare, difficult to diagnose, and represents a severe and chronic phenotype of the adult-onset illness. A study of childhood-onset psychoses has been ongoing at the National Institute of Mental Health (NIMH) since 1990, where children with COS and severe atypical psychoses (provisionally labeled "multidimensionally impaired" or MDI by the NIMH team) are studied prospectively along with all first-degree relatives. COS subjects have robust cortical gray matter (GM) loss during adolescence, which appears to be an exaggeration of the normal cortical GM developmental pattern and eventually mimics the pattern seen in adult-onset cases as the children become young adults. These cortical GM changes in COS are diagnostically specific and seemingly unrelated to the effects of medications. Furthermore, the cortical GM loss is also shared by healthy full siblings of COS probands suggesting a genetic influence on the abnormal brain development.

Annotation: what electrical brain activity tells us about brain function that other techniques cannot tell us - a child psychiatric perspective

BACKGROUND

Monitoring brain processes in real time requires genuine subsecond resolution to follow the typical timing and frequency of neural events. Non-invasive recordings of electric (EEG/ERP) and magnetic (MEG) fields provide this time resolution. They directly measure neural activations associated with a wide variety of brain states and processes, even during sleep or in infants. Mapping and source estimation can localise these time-varying activation patterns inside the brain.

METHODS

Recent EEG/ERP research on brain functions in the domains of attention and executive functioning, perception, memory, language, emotion and motor processing in ADHD, autism, childhood-onset schizophrenia, Tourette syndrome, specific language disorder and developmental dyslexia, anxiety, obsessive-compulsive disorder, and depression is reviewed.

RESULTS

Over the past two decades, electrophysiology has substantially contributed to the understanding of brain functions during normal development, and psychiatric conditions of children and adolescents. Its time resolution has been important to measure covert processes, and to distinguish cause and effect.

CONCLUSIONS

In the future, EEG/ERP parameters will increasingly characterise the interplay of neural states and information processing. They are particularly promising tools for multilevel investigations of etiological pathways and potential predictors of clinical treatment response.

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.

Forty-two-years later: the outcome of childhood-onset schizophrenia

This paper describes the long-term course of 76 patients who had been consecutively admitted to the Department of Child and Adolescent Psychiatry, Philipps University, between 1920 and 1961 with a suspected diagnosis of childhood-onset schizophrenia. By means of a consensus analysis of available data in accordance with ICD-10 criteria, the diagnosis of schizophrenia was confirmed in only 50% of the original sample (n = 38, childhood-onset schizophrenia group); whereas the rest of the sample were allotted other diagnoses (n = 38, non-schizophrenia group). A follow-up investigation was conducted, interviewing all available patients, if possible, or their first-degree relatives or doctors. In the childhood-onset schizophrenia group, age at onset (mean +/- S.D.) was 12.7 +/- 2.5 (range 5-14) years and age at follow-up was 55.0 +/- 4.8 (range 42-62) years. The outcome of this group was poor. According to the Global Assessment Scale (GAS), only 16% had a good (GAS score 71-100) and 24% had a moderate (GAS score 41-70) outcome. In the 16 childhood-onset schizophrenia patients who could be personally investigated at follow-up, 10 (62.5%) displayed severe or moderate depressive symptoms according to the BPRS depressive score. The death rate (including suicide) was significantly higher in the schizophrenia group (n = 15; 39.5%) than in the non-schizophrenia group (n = 7; 18.4%). A comparison of the life-time diagnoses of the total sample (n = 76) at follow-up with the ICD-10 diagnoses made retrospectively revealed a diagnostic stability in 69 (91%) and a change of diagnosis in 7 (9%) cases, among them 4 who were originally diagnosed as having childhood-onset schizophrenia.

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.

Superior temporal gyrus differences in childhood-onset schizophrenia

The posterior superior temporal gyrus (STG) is the approximate site of Wernicke's area, a language region, which in previous studies has been reported to be abnormal in adults with schizophrenia. The present study assesses volumetric differences in the superior temporal gyrus of subjects with childhood-onset schizophrenia (COS). MRI scans of 18 subjects diagnosed with childhood-onset schizophrenia and 16 age- and sex-matched normals were analyzed to assess possible volume differences. The COS subjects displayed significant enlargement of the right posterior superior temporal gyrus, showing white matter increases bilaterally in this region. Our findings are consistent with studies that have found increased volumes in temporal lobe regions in COS and may provide a possible neural correlate for the language impairment observed in COS patients.

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.

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.

Lessons from childhood-onset schizophrenia

Childhood-onset schizophrenia (with an onset of psychosis by age 12) is a rare and severe form of the disorder which is clinically and neurobiologically continuous with the adult-onset disorder. Very early onset diseases provide an opportunity to look for more salient or striking risk or etiologic factors in a possibly more homogenous patient population. For the 47 patients with very early onset schizophrenia studied to date, there were more severe premorbid neurodevelopmental abnormalities, more cytogenetic anomalies, and potentially greater family histories of schizophrenia and associated spectrum disorders than later onset cases. There was no evidence for relatively increased obstetrical complications or environmental stress. These data, while preliminary, suggest a very early age of onset of schizophrenia may be secondary to greater genetic vulnerability. It is anticipated that future genetic studies of these patients may provide important etiologic information.

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.

Blink rate in pediatric complex partial seizure disorder

This study examined spontaneous blink rate, a putative measure of dopamine function, in 30 children with complex partial epilepsy and 61 normal children. The children with epilepsy had significantly lower blink rates than the normal children in a conversation and a verbal recall task, particularly if they had a schizophrenia-like psychosis, EEG evidence for left focal epileptic activity, illogical thinking, discourse deficits, and distractibility. They modulated their blink rates across a listening, a conversation, and a verbal recall task like the normal children. Given previously reported low blink rates in schizophrenic children, these findings suggest that children with complex partial epilepsy or schizophrenia might have similar biological features.

Quantitative morphology of the cerebellum and fourth ventricle in childhood-onset schizophrenia

OBJECTIVE

Studies have suggested that the maldeveloped neural circuitry producing schizophrenic symptoms may include the cerebellum. The authors found further support for this hypothesis by examining cerebellar morphology in severely ill children and adolescents with childhood-onset schizophrenia.

METHOD

Anatomic brain scans were acquired with a 1.5-T magnetic resonance imaging scanner for 24 patients (mean age = 14.1 years, SD = 2.2) with onset of schizophrenia by age 12 (mean age at onset = 10.0 years, SD = 1.9) and 52 healthy children. Volumes of the vermis, inferior posterior lobe, fourth ventricle, and total cerebellum and the midsagittal area of the vermis were measured manually.

RESULTS

After adjustment for total cerebral volume, the volume of the vermis and the midsagittal area and volume of the inferior posterior lobe remained significantly smaller in the schizophrenic patients. There was no group difference in total cerebellar or fourth ventricle volume.

CONCLUSIONS

These findings are consistent with observations of small vermal size in adult schizophrenia and provide further support for abnormal cerebellar function in childhood- and adult-onset schizophrenia.

Formal thought disorder and psychopathology in pediatric primary generalized and complex partial epilepsy

OBJECTIVE

To examine whether formal thought disorder and psychopathology occurred in children with complex partial seizures (CPS) rather than children with primary generalized epilepsy with absences (PGE) or nonepileptic children.

METHOD

Formal thought disorder was coded in 30 children with CPS, 24 children with PGE, and 61 nonepileptic children, and structured interview-based psychiatric diagnoses were obtained for the epileptic subjects.

RESULTS

The CPS subjects had significantly more illogical thinking than the PGE and nonepileptic children. The severity of their illogical thinking was related to global cognitive dysfunction and a schizophrenia-like psychosis. Age of onset and seizure control, however, were significantly associated with the severity of illogical thinking in the PGE group. One or more psychiatric diagnoses were found in 63% of the CPS and 54% of the PGE patients, particularly if they had global cognitive deficits.

CONCLUSION

Illogical thinking, associated with cognitive dysfunction or schizophrenia-like symptoms, might be a feature of pediatric CPS. Psychopathology might be related to global cognitive dysfunction in pediatric CPS and PGE.

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.

Information-processing deficits across childhood- and adult-onset schizophrenia

Event-related potentials were recorded for childhood- and adult-onset schizophrenia subjects performing the span of apprehension (Span) task, which is sensitive to vulnerability factors in schizophrenia. Subjects responded to the onset of the Span arrays in a reaction time condition and then responded differentially to the presence of one of two target letters in the Span condition. While neither the childhood- nor the adult-onset group exhibited abnormalities in preparatory contingent negative variation activity, both groups produced significantly less endogenous negative activity between 100 and 300 ms after Span stimulus onset than age-matched normals. This endogenous negative activity reflects attentional effort associated with serial search and stimulus identification. These results support the position that schizophrenia subjects are impaired in their ability to allocate adequate attentional resources for processing Span stimuli. Moreover, the similarity of this information-processing deficit in the two groups suggests that childhood- and adult-onset schizophrenia lie on a continuum in this regard.

Childhood-onset schizophrenia: an NIMH study in progress

An ongoing study of the phenomenology, genetics, neuropsychology, physiology (eye tracking, autonomic responsivity), neuroimaging, biochemistry, and pharmacology of childhood-onset schizophrenia is described, and pilot data are presented for the first 22 subjects. Differentiation from autism "spectrum" disorders and other poorly defined, severe neurodevelopmental disorders is needed. Eye tracking and autonomic results are similar to patterns seen in later-onset schizophrenia and possibly more striking. Magnetic resonance imaging showed larger left frontal ventricular horn area for the schizophrenia subjects, larger left caudate, and lack of normal caudate asymmetry. Fluorodeoxyglucose positron emission tomography during an auditory continuous performance task revealed decreased right parietal/occipital glucose metabolic rate in the schizophrenia subjects, which may be secondary to poor attentional performance, and increased glucose metabolic rate in three left frontal regions, a left parietal region, and the right putamen. Clozapine has been effective and well tolerated in an open trial with 12 adolescents who responded poorly to typical neuroleptics; 16 subjects have been enrolled in a double-blind comparison of haloperidol and clozapine. Longitudinal study of this narrowly defined and possibly more homogeneous group of very early-onset schizophrenia subjects will be relevant to current neurodevelopmental theories addressing the role of puberty, progression of pathology, and continuity or discontinuity with later-onset schizophrenia.

Cognitive/neuropsychological studies of children with a schizophrenic disorder

This article summarizes a series of cognitive/neuropsychological studies of children with schizophrenia. One set of studies, which surveyed a broad range of neuropsychological functions, revealed no evidence that children with schizophrenia are consistently impaired in sensory, perceptual, or language functions. Rather, the studies showed that children with schizophrenia performed poorly on tasks requiring sensory, perceptual, and language processing that made extensive demands on information-processing capacity. A second series of studies, which examined visual information processing by manipulating the processing demands of span of apprehension tasks, yielded similar findings. The key characteristic of tasks that elicit impaired performance in children with schizophrenia is that the task makes extensive demands on processing resources. This suggests that these children have limited information-processing capacity. Three hypotheses are proposed concerning the cognitive processes that are impaired in children with schizophrenia: (1) the cognitive processes that seem to be impaired in these children are part of a more general, hierarchically organized attention system; (2) the component processes of the system are subserved by different brain structures; and (3) the structures are part of a network that includes the frontal lobe and thalamus in interaction with the reticular activating system.

Middle childhood onset of interictal psychosis

The authors describe three children (mean age = 7.8 years) with complex partial epilepsy, left temporal lobe involvement, and interictal schizophrenia-like psychosis. As described in adults with complex partial epilepsy, these children met DSM-III criteria for schizophrenia, their affect was intact, and they demonstrated no negative signs of schizophrenia. Unlike adult epileptic patients, these children demonstrated psychotic symptomatology despite inadequate seizure control and after a short latency period. The possible role of early onset seizures, temporal lobe lesions, and kindling on the developing brain are discussed.

The gait of hypotonic schizophrenic children

The gait of seven hypotonic schizophrenic children aged between five and eight years was compared with that of seven normal children aged between seven and eight years. Electromyographic studies revealed that in schizophrenic children the tibialis anterior was 'on' during a significantly smaller proportion of the stance phase than in the age-matched controls, and that the quadriceps muscle was 'on' during a significantly smaller proportion of the swing phase than in the controls. In addition, the gait of the schizophrenic children tended to be broad-based and slow, consisting of smaller steps in a longer pace period. In general, the gait of the schizophrenic children resembled that of younger, inexperienced walkers.

Childhood psychosis and 24-h rhythms: A behavioral and psychophysiological analysis

Three investigations were performed to examine behavioral and physiological variation with respect to rhythmicity in psychotic children. Case report I observed periodicity in certain stereo-typed behaviors, and provided data on extinction of self-stimulation and self-injurious behavior for a 72 h period. Case report II monitored psychophysiological reaction in an orienting response paradigm. Results indicated significant changes as a function of time of day. Study I indicated differences in amplitude of the temperature rhythm between normal controls and the psychotic group. The results of these investigations are discussed in terms of their potential for etiological and diagnostic research. Further, specific treatment implications are presented.

Effects of the vestibular system on human development, part 2: Effects of vestibular stimulation on mentally retarded, emotionally disturbed, and learning-disabled individuals

In Part 1 of this two-part series, studies concerned with the effects of vestibular stimulation on human development and function were reviewed and some implications for therapy were suggested. In Part 2, three categories of dysfunction with possible links to the vestibular system are discussed. Studies in the category of mental retardation evaluate motor development and sensory preference. Possible vestibular associations with emotional disturbance are examined by review of studies concerned with etiology, motor activity, speech, and clinical observations. A brief review of studies concerned with early identification and speech and language factors of learning-disabled children constitutes the third category. Interpretations are drawn and some implications for therapy are made.

[Childhood and prepuberal schizophrenia ]

The author gives a short review of modern aspects concerning schizophrenia in childhood. Very early forms of the preschool age are excluded for nosological reasons. Age-specific phenomenology, differential diagnosis, course and prognosis as well as the outcome of the disease are discussed.

Recent studies of psychophysiology in schizophrenia

A general introduction is given and followed by a review of recent literature under the following subheadings: electrodermal activity, cardiovascular activity, smooth pursuit eye movement, electroencephalogram, and evoked potentials. An attempt is made to assess the clinical significance of the findings reported in each area and to indicate directions for future investigation. The feasibility of defining homogeneous subgroups in schizophrenia using psychophysiological parameters is also considered. The review concludes with the recommendation that peripheral psychophysiological studies entailing (1) comprehensive recording of brain electrical activity and (2) behavioral experimentation on variables thought to be influenced by schizophrenia (e.g., sustained attentional ability) are promising directions for future research. Relationships between behavioral and psychophysiological variables determined by such studies (and possibly subgroupings) may then become the basis for neurophysiological-neurochemical investigations of specific abnormalities underlying such relationships and subgroups.

Habituation and conditioning of electrodermal responses in high risk children

Measures of skin conductance during rest and during experiments testing habituation and conditioning of the skin conductance response were obtained from 42 10-year-old male children, of whom 12 were at risk for schizophrenia and 30 constituted low risk controls. While typical habituation curves for skin conductance response were obtained from both sets of offspring, no differences were found between high and low risk subjects on trials to habituation, response magnitude, latency, or number of spontaneous responses. However, there was evidence suggestive of differential conditioning in the two groups of children as a function of risk status. High risk offspring produced significantly larger skin conductance responses to conditioning test trials than low risk offspring. High risk subjects were also significantly more responsive to the unconditioned stimulus (loud white noise) than low risk subjects, but half-amplitude recovery time did not differentiate between the two groups of children. Finally, high risk offspring manifested lower levels of tonic conductance during conditioning, but not during resting or habituation. These results lend support to two important recent findings by Mednick concerning autonomic differences between high and low risk children, but do not confirm his findings regarding generalization and half-amplitude recovery time.

Computerized Electroencephalogram. A model of understanding the brain function in childhood psychosis and its treatment

Computer analysis of the electroencephalogram (CEEG) in psychotic children before and after pharmacotherapy, normal children of schizophrenic mothers, and matched normal children of normal parents indicated significant intergroup differences. The psychotic children had more slow, as well as very fast, EEG waves. With drug therapy the EEG showed a partial "normalization," as fast EEG activity decreased. The EEG and auditory evoked potential of children of schizophrenic mothers were strikingly similar to those of psychotic children and schizophrenic adults, with significant decreases of the average EEG amplitude and the evoked potential latencies. Psychotic children were distinctly differentiated from the normal children by discriminant function analysis of the EEG and EP. Quantitative analysis of brain functions in the mentally ill can help determine the neurophysiological correlates of behavior, a more scientific diagnostic classification, prognosis, and selection of therapy.

Symptom formation as an expression of disordered information processing in schizophrenic children

The possible mechanisms that underlie symptom formation in childhood schizophrenia are discussed. A body of research evidence has been reviewed in which dissociation in relation to information processing was examined for its possible consequence in the formation and expression of symptomatology. Schizophrenic children have been found to exhibit dissociation of integrative processes among the sense systems at a level which is several years below normal expectation, and they usually fail to improve as age increases. The clinical manifestations of schizophrenia are considered to be the consequence of the conflict, distortion, and deprivation that derive from failure in information processing. These consequences can best be understood within a developmental framework which encompasses the different age-stages of function. This approach to the understanding of symptom formation is discussed in relationship to other evidence which suggests that primary neurological abnormality is present in schizophrenic children. Thus the identification of abnormality of intersensory integrative function may increase our understanding of etiology as well as of the mechanisms of symptom formation in schizophrenic children.