Efficacy of Sulforaphane in Treatment of Children with Autism Spectrum Disorder: A Randomized Double-Blind Placebo-Controlled Multi-center Trial

Sulforaphane has been reported to possibly improve core symptoms associated with autism spectrum disorders from mostly small size studies. Here we present results of a larger randomized clinical trial (N = 108) in China. There were no significant changes in caregiver rated scales between sulforaphane and placebo groups. However, clinician rated scales showed a significant improvement in the sulforaphane group, and one third of participants showed at least a 30% decrease in score by 12 weeks treatment. The effects of sulforaphane were seen across the full range of intelligence and greater in participants over 10 years. Sulforaphane was safe and well-tolerated even for young children. The inconsistent results between caregiver and clinician rated scales suggest more clinical trials are needed to confirm our findings.

The association between area-level residential instability and gray matter volume changes

Introduction

Area-level residential instability (ARI), an index of social fragmentation, has been shown to explain the association between urbanicity and psychosis. Urban upbringing has been shown to be associated with decreased gray matter volumes (GMV)s of brain regions corresponding to the right caudal middle frontal gyrus (CMFG) and rostral anterior cingulate cortex (rACC).

Objectives

We hypothesize that greater ARI will be associated with reduced right posterior CMFG and rACC GMVs.

Methods

Data were collected at baseline as part of the North American Prodrome Longitudinal Study. Counties where participants resided during childhood were geographically coded using the US Censuses to area-level factors. ARI was defined as the percentage of residents living in a different house five years ago. Generalized linear mixed models tested associations between ARI and GMVs.

Results

This study included 29 HC and 64 CHR-P individuals who were aged 12 to 24 years, had remained in their baseline residential area, and had magnetic resonance imaging scans. ARI was associated with reduced right CMFG (adjusted β = -0.258; 95% CI = -0.502 – -0.015) and right rACC volumes (adjusted β = -0.318; 95% CI = -0.612 – -0.023). The interaction terms (ARI X diagnostic group) in the prediction of both brain regions were not significant, indicating that the relationships between ARI and regional brain volumes held for both CHR-P and HCs.

Conclusions

Like urban upbringing, ARI may be an important social environmental characteristic that adversely impacts brain regions related to schizophrenia.

Disclosure

No significant relationships.

Identification of urinary metabolites that correlate with clinical improvements in children with autism treated with sulforaphane from broccoli

Background

Children with autism spectrum disorder (ASD) have urinary metabolites suggesting impairments in several pathways, including oxidative stress, inflammation, mitochondrial dysfunction, and gut microbiome alterations. Sulforaphane, a supplement with indirect antioxidant effects that are derived from broccoli sprouts and seeds, was recently shown to lead to improvements in behavior and social responsiveness in children with ASD. We conducted the current open-label study to determine if we could identify changes in urinary metabolites that were associated with clinical improvements with the goal of identifying a potential mechanism of action.

Methods

Children and young adults enrolled in a school for children with ASD and related neurodevelopmental disorders were recruited to participate in a 12-week, open-label study of sulforaphane. Fasting urinary metabolites and measures of behavior (Aberrant Behavior Checklist—ABC) and social responsiveness (Social Responsiveness Scale—SRS) were measured at baseline and at the end of the study. Pearson’s correlation coefficient was calculated for the pre- to post-intervention change in each of the two clinical scales (ABS and SRS) versus the change in each metabolite.

Results

Fifteen children completed the 12-week study. Mean scores on both symptom measures showed improvements (decreases) over the study period, but only the change in the SRS was significant. The ABC improved − 7.1 points (95% CI − 17.4 to 3.2), and the SRS improved − 9.7 points (95% CI − 18.7 to − 0.8). We identified 77 urinary metabolites that were correlated with changes in symptoms, and they clustered into pathways of oxidative stress, amino acid/gut microbiome, neurotransmitters, hormones, and sphingomyelin metabolism.

Conclusions

Urinary metabolomics analysis is a useful tool to identify pathways that may be involved in the mechanism of action of treatments targeting abnormal physiology in ASD.

Trial registration

This study was prospectively registered at clinicaltrials.gov (NCT02654743) on January 11, 2016.

GSTP1 Loss results in accumulation of oxidative DNA base damage and promotes prostate cancer cell survival following exposure to protracted oxidative stress

BACKGROUND

Epigenetic silencing of glutathione S-transferase π (GSTP1) is a hallmark of transformation from normal prostatic epithelium to adenocarcinoma of the prostate. The functional significance of this loss is incompletely understood. The present study explores the effects of restored GSTP1 expression on glutathione levels, accumulation of oxidative DNA damage, and prostate cancer cell survival following oxidative stress induced by protracted, low dose rate ionizing radiation (LDR).

METHODS

GSTP1 protein expression was stably restored in LNCaP prostate cancer cells. The effect of GSTP1 restoration on protracted LDR-induced oxidative DNA damage was measured by GC-MS quantitation of modified bases. Reduced and oxidized glutathione levels were measured in control and GSTP1 expressing populations. Clonogenic survival studies of GSTP1- transfected LNCaP cells after exposure to protracted LDR were performed. Global gene expression profiling and pathway analysis were performed.

RESULTS

GSTP1 expressing cells accumulated less oxidized DNA base damage and exhibited decreased survival compared to control LNCaP-Neo cells following oxidative injury induced by protracted LDR. Restoration of GSTP1 expression resulted in changes in modified glutathione levels that correlated with GSTP1 protein levels in response to protracted LDR-induced oxidative stress. Survival differences were not attributable to depletion of cellular glutathione stores. Gene expression profiling and pathway analysis following GSTP1 restoration suggests this protein plays a key role in regulating prostate cancer cell survival.

CONCLUSIONS

The ubiquitous epigenetic silencing of GSTP1 in prostate cancer results in enhanced survival and accumulation of potentially promutagenic DNA adducts following exposure of cells to protracted oxidative injury suggesting a protective, anti-neoplastic function of GSTP1. The present work provides mechanistic backing to the tumor suppressor function of GSTP1 and its role in prostate carcinogenesis.

HPA axis function and symptoms in adolescents at clinical high risk for schizophrenia

BACKGROUND

Stress sensitivity and HPA axis activity may be relevant to the development and expression of psychotic disorders. Cortisol secretion has been associated with positive symptoms both in patients with psychotic disorders and in young people at clinical risk for psychosis. Herein, we aimed to replicate these findings, to determine which positive symptoms may be associated with cortisol levels, and to explore any associations with affective symptoms and impaired stress tolerance.

METHODS

Thirty-one clinical high risk patients were evaluated in cross-section for associations between salivary cortisol levels upon clinic entry at 11 am, demographic variables, and clinical symptoms.

RESULTS

Salivary cortisol levels were unrelated to medication exposure or demographics, except for higher levels in the ten females studied. Salivary cortisol bore no relationship to overall positive symptom severity but was associated with anxiety, as well as with suspiciousness and impaired stress tolerance, which were themselves highly intercorrelated.

CONCLUSIONS

Cortisol secretion in the context of a putative novel social situation (i.e. clinic entry) may be a biological correlate of suspiciousness, impaired stress tolerance and affective symptoms in individuals vulnerable to developing psychosis. These associations are consistent with findings from experience sampling studies in individuals at risk for psychosis as well as basic studies of animal models of schizophrenia.

The timing of neurodevelopmental abnormality in schizophrenia: an integrative review of the neuroimaging literature

In this paper we will review recent neuroimaging research in schizophrenia, with an aim to critically evaluate several recent proposals concerning the nature and the timing of the neuroanatomic abnormalities underlying the disorder. Specifically, enlargement of cerebrospinal fluid spaces, deficits in cortical gray matter, and reduced volume of mesiotemporal structures have all been reported in patients in the first episode of schizophrenia, their first-degree relatives, and individuals with schizotypal personality disorder, supporting the possibility that these abnormalities reflect a genetically mediated neurodevelopmental disorder. These findings from the empirical literature will be synthesized from the perspective of dual cytoarchitectonic trends theory of neurodevelopment, as well as in relation to current conceptions of the schizophrenia prodrome. We believe that the evidence shows that sufficient groundwork has been laid to begin longitudinal neuroimaging studies of adolescents at clinical risk for schizophrenia, in order to more definitively determine the pathophysiology of the disorder. Such information could have significant implications in terms of understanding the prediction, treatment, and ultimately the prevention of schizophrenia.

Neurodevelopmental models of schizophrenia: pathophysiologic synthesis and directions for intervention research

This paper examines contemporary models of the pathophysiology of schizophrenia from a neurodevelopmental perspective. Specifically, this article reviews recent research in the neuropathology, neuroimaging, and developmental psychopathology of schizophrenia, with an aim to critically evaluate several recent proposals concerning the nature and timing of both the neuroanatomic abnormalities underlying the disorder and their behavioral manifestations. Findings from the empirical literature are synthesized from the perspective of dual cytoarchitectonic trends theory of neurodevelopment, as well as in relation to current conceptions of the schizophrenia prodrome. The evidence shows that sufficient groundwork has been laid to begin longitudinal neuroimaging studies of adolescents at clinical risk for schizophrenia, to determine more definitively the pathophysiology of the disorder. Such information could have significant implications in terms of understanding the prediction, treatment, and, ultimately, prevention of schizophrenia.

Attention, memory, and motor skills as childhood predictors of schizophrenia-related psychoses: the New York High-Risk Project

OBJECTIVE

Childhood neurobehavioral deficits in offspring of schizophrenic, affectively ill, and psychiatrically normal parents were evaluated as predictors of schizophrenia-related psychoses in adulthood.

METHOD

The offspring were tested with neurobehavioral measures at 7-12 years of age and assessed in mid-adulthood for axis I diagnoses. The relationships of childhood deficits in attention, verbal memory, and gross motor skills to adulthood schizophrenia-related psychoses were examined in separate path analyses by using logistic regression equations. Sensitivity and specificity were determined for each of the childhood dysfunctions.

RESULTS

For the offspring of schizophrenic parents, childhood deficits in verbal memory, gross motor skills, and attention identified 83%, 75%, and 58%, respectively, of the subjects with schizophrenia-related psychoses; 50% were identified by all three variables combined. False positive rates in subjects who did not develop schizophrenia-related psychoses ranged from 18% for those with deficits in attention during childhood to 28% for those with deficits in memory. The three variables had low deficit rates in the offspring of the other two parental groups and were not associated with other psychiatric disorders in any group.

CONCLUSIONS

Schizophrenia-related psychoses in adulthood are distinguished in subjects at risk for schizophrenia by childhood deficits in verbal memory, gross motor skills, and attention. The findings suggest that deficits in these variables are relatively specific to schizophrenia risk and may be indicators of the genetic liability to schizophrenia.

Cognitive and behavioral precursors of schizophrenia

Attentional deficits are well-established characteristics of patients with schizophrenia and their at-risk offspring, suggesting a biological connection between attention and schizophrenia. The goal of this study is to clarify the developmental role of attention in the illness. Data has been collected from 87 subjects at high and low risk for schizophrenia who have participated in the New York High-Risk Project from 1977 to the present. Individuals are considered to be at high risk if either or both of their parents has schizophrenia. Analyses of attention and global behaviors, measured at intervals from about 12 to 26 years of age, indicate (a) attentional deficits can be reliably detected in high-risk children who will develop future schizophrenia-spectrum disorders (the prespectrum [PSP] group); (b) these deficits are stable, enduring over time, and appear to reflect a compromised attentional capacity; (c) attention is not affected by the onset of illness in the PSP group; (d) for all subjects, attention and global behaviors follow independent developmental pathways; and (e) behavioral difficulties, but not attention deficits, appear to be highly sensitive to environmental factors, especially rearing by a mentally ill parent. It is concluded that in PSP individuals impaired attention probably results from prenatal developmental abnormalities (possibly on the cellular level) and is likely to be a marker of a biological vulnerability to schizophrenia. In addition, attentional deficits, as opposed to early behavioral difficulties, are concluded to be a useful first step in screening for youngsters in need of early intervention.

Hillside study of risk and early detection in schizophrenia

BACKGROUND

The Hillside Study of Risk and Early Detection in Schizophrenia is a prospective study of young probands (ages 14-28) and their at-risk siblings (ages 14-24). A major goal is the identification of early predictors of illness that will facilitate intervention. The project design and pilot study are discussed.

METHOD

Fifteen adolescents were compared to 14 typical age-of-onset adults, all undergoing their first hospitalisation for schizophrenia.

RESULTS

There were no differences between adolescents and adults on any of the measures administered (i.e. attention, eye tracking, neurocognitive or clinical). In addition, for the sample overall, no association was found between neurocognitive functions and clinical state, either at admission or after treatment.

CONCLUSIONS

Individuals with adolescent onset of schizophrenia are considered to be representative of schizophrenia in general. Furthermore, neurocognitive deficits and clinical symptoms are concluded to be two independent classes of risk indicators.

Sustained attention in combat-related posttraumatic stress disorder

There is substantial evidence that PTSD patients have information processing abnormalities for stimuli that are highly relevant to the traumas they have endured. The goal of the present study was to examine whether this extends to neutral stimuli as well. Twenty-four male Vietnam combat veterans with PTSD were compared to fifteen normal male comparison subjects on their performance on a sensitive measure of sustained attention, the Continuous Performance Test-Identical Pairs version (CPT-IP). PTSD subjects did not differ from controls in their ability to discriminate target stimuli from background noise on the CPT. Additionally they performed as well as controls, even in the presence of external distraction. Thus, this study did not find a generalized deficit in attention associated with PTSD on the CPT-IP. Nevertheless, further clarification of the nature of the information processing disturbance in PTSD is warranted.

Attention and clinical symptoms in schizophrenia

Attentional deficits, long established to characterize patients with schizophrenia spectrum disorders, have traditionally been regarded as part of the disorder's clinical syndrome. In this paper we provide evidence to indicate that: a) impaired attention is a dimension of schizophrenia that is independent of clinical state, and b) that attention does not appear to respond to the medication (i.e. standard neuroleptics) most typically used to treat clinical symptoms. Since intact attention and other cognitive processes appear critical to successful functioning in the community after hospital discharge, these findings have major implications for treatment.

An assessment of cognitive function and mood in chronic fatigue syndrome

Data were gathered regarding the associates of chronic fatigue syndrome (CFS) with: (1) speed of cognitive processing, (2) motor speed, (3) ability to sustain attention, and (4) mood. Patients were given a brief neuropsychological test battery before and after double-blind treatment with terfenadine or placebo and completed a daily mood rating scale (Positive and Negative Affect Schedule) during the study. CFS patients exhibited slower cognitive processing and motor speed and lower positive affect, as compared to data reported from previous studies of healthy subjects and other patient groups; however, CFS patients did not exhibit deficits in sustained attention in comparison to other groups. The CFS patients' ability to attend to verbal versus figural stimuli and mood ratings were different from those reported in studies of patients with depression. Because of methodological limitations, these findings are preliminary, but they encourage further assessment of cognitive dysfunction and mood in CFS.

Susceptibility of idarubicin, daunorubicin, and their C-13 alcohol metabolites to transport-mediated multidrug resistance

The intracellular pharmacokinetics and cytotoxicity of idarubicin (IDA), daunorubicin (DNR), and their corresponding C-13 alcohol metabolites, idarubicinol (IDAol) and daunorubicinol (DNRol), were studied in drug-sensitive HL-60/W human leukemia cells, and in two multidrug-resistant (MDR) sublines, HL-60/Vinc (overexpress P-glycoprotein, Pgp) and HL-60/Adr (overexpress multidrug resistance-associated protein, MRP). Intracellular drug accumulation (1 micrograms/mL) and retention were measured by flow cytometry. Mean intracellular steady-state concentration (Css, fluorescence units/cell) and area under the intracellular drug concentration x time curve (AUC, Fl.U/cell.min) were calculated. Relative to the values for the respective drugs in HL-60/W cells, the Css and AUC of IDA were much higher than those of DNR in the MDR cell lines, with Css and AUC of IDAol intermediate between IDA and DNR. In the MDR cell lines, the MDR modulator cyclosporine A (CsA), in concentrations of 0.3 to 30 mumol/L, caused minimal effects on 3-hr IDA accumulation, intermediate enhancement of IDAol accumulation, and greatest enhancement of DNR accumulation. The MDR cell lines were much less resistant to IDA (3- to 16-fold) than to DNR (65- to 117-fold). This difference was not the result of IDA being more potent than DNR, since the sensitivity of HL-60/W cells to IDA differed from their sensitivity to DNR by < 2-fold. The cellular pharmacokinetics and cytotoxicity of IDA in MDR human breast carcinoma cells MCF-7/AdrVp, which overexpress the putative MDR transporter P-95, were far superior to those of DNR, and were comparable to these parameters for IDA in parental MCF-7/W cells. These studies demonstrate that the cellular pharmacology and cytotoxicity of IDA in MDR cell lines that overexpress MRP, Pgp, or P-95 are more advantageous than those of DNR, suggesting that IDA is less susceptible to the transport-mediated MDR mechanism manifested. IDA is not completely invulnerable to MDR, however, since the MDR sublines studied did display a demonstrable level of resistance to IDA, compared with their drug-sensitive counterparts. IDAol, the major plasma metabolite of IDA, demonstrated behavior intermediate between the MDR-susceptible drug DNR and its parent compound, suggesting that its cytotoxic action is subject to transport-mediated cellular defenses.(ABSTRACT TRUNCATED AT 400 WORDS)

Distractibility in schizophrenia

This study examined the effects of neuroleptic medication on the allocation of attentional resources to distracting stimuli in patients with schizophrenia. Twenty-five patients were tested twice (medication-free and after medication stabilization) on the Identical Pairs versions of the Continuous Performance Test under both distraction and no-distraction conditions. Sixteen patients were chronically ill adults and nine patients were young neuroleptic-native patients in the early stages of illness. Results indicated that neuroleptic treatment did not improve distractibility for either group and that both groups were comparably distractible. These findings suggest that medication does not improve the misallocation of attention to distracting stimuli in patients with schizophrenia.

Synergistic reversal of multidrug-resistance phenotype in acute myeloid leukemia cells by cyclosporin A and cremophor EL

Cremophor (Crem) EL, the vehicle for intravenous delivery of cyclosporin A (CsA), has been reported to counteract multidrug resistance (MDR) in P-glycoprotein (Pgp)-over-expressing cell lines. Because of this, we sought to determine whether Crem functions independently as a modulator of MDR in blast cells obtained from acute myelogenous leukemia (AML) patients, and the nature of its interaction in combination with CsA in reversing an MDR phenotype. In the phenotypically classical MDR AML cell lines HL-60/Vinc (overexpresses Pgp) or HL-60/AR (does not overexpress Pgp), the dose causing half-maximum enhancement (D50) of daunorubicin (DNR, 1 micrograms/mL, 3 hours) accumulation was achieved by the combination of CsA and Crem (CsA/Crem) at 1.2 mumol/L CsA. In contrast, the D50 for Crem alone was approached at an amount that would be needed to suspend 6.2 mumol/L CsA for HL-60/Vinc, and 81 mumol/L CsA for HL-60/AR. The D50 concentrations for CsA alone (dissolved in ethanol, which does not alter DNR accumulation) were also higher than those for CsA/Crem, being 6.5 mumol/L for HL-60/Vinc, and 3.1 mumol/L for HL-60/AR. The maximum absolute level of enhancement of DNR accumulation (Emax) in each cell line was approximately equivalent for CsA/Crem or CsA alone, and was equal to the 3 hr intracellular DNR accumulation observed in parental, drug sensitive HL-60/W cells. For Crem alone, HL-60/AR and HL-60/Vinc cells showed markedly different responses: HL-60/Vinc cells attained intracellular DNR content comparable to HL-60/W, whereas HL-60/AR cells achieved only approximately 35% of this level. Multiple-drug effects were analyzed by calculation of the Combination Index (Chou and Talalay, Adv Enzyme Regul 22:27, 1984), which indicated that CsA and Crem are synergistic in causing enhancement of DNR accumulation in these MDR HL-60 cell lines. In blasts from AML patients, 5 mumol/L CsA/Crem or an equivalent amount of Crem alone each caused significant (P < .001) enhancement of DNR accumulation (60 AML-patient marrow samples) or DNR retention (51 AML-patient marrows). Similarly, CsA/Crem or Crem alone caused significant (P < .01) enhancement of the cytotoxicity of DNR in 36 AML blast cell specimens. The degree of enhancement of accumulation/retention or cytotoxicity by CsA/Crem was approximately equivalent to that obtained with Crem alone. These studies indicate that Crem can reverse an MDR phenotype in patient AML blast cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Report of a workshop on genetic linkage studies in schizophrenia

A workshop on genetic linkage studies in schizophrenia was held at Columbia University's Arden House Conference Center in October 1989. This report summarizes the contents of invited talks by Drs. Arno Motulsky and T. Conrad Gilliam and the discussions at the five workshop sessions. Topics of the workshop sessions were (1) diagnostic boundaries and hierarchies in schizophrenia, (2) genetic models and linkage parameters, (3) selection and ascertainment of pedigrees, (4) future extensions of molecular genetics strategies, and (5) possibilities for future collaboration.

Auditory event-related potentials in children at risk for schizophrenia: the complete initial sample

Event-related potentials (ERPs) were recorded from children of schizophrenic parents, children of parents with affective disorders, and children of parents without a history of psychiatric illness. ERPs were elicited during a modification of the "oddball" paradigm, in which two infrequents (a change in pitch and a missing stimulus) were embedded in a series of frequent background events. The data were recorded from electrodes located at midline frontal, central, parietal, and occipital scalp sites. Diagnostic assessments of the parents were performed using the Schedule for Affective Disorders and Schizophrenia-Lifetime Version (SADS-L) and Research Diagnostic Criteria (RDC). Behavioral assessments of the children were made with a modified version (BGAS) of the Global Assessment Scale. ERP amplitudes for several electrophysiological events were compared among groups for target and nontarget stimuli using analyses of of variance of both factor score and baseline to peak measures. No systematic differences suggesting waveform abnormalities in the children of schizophrenic parents (high-risk subjects) were found. However, when the results were analyzed using only those children whose parents had a "pure" diagnosis of either schizophrenia or affective disorder, the children of affectively disordered parents (psychiatric control subjects) showed significantly lower N100 amplitudes (to the frequent event only) than either the normal control or high-risk subjects. No consistent behavioral differences among the three groups emerged. Since only a small percentage of children at risk will eventually develop schizophrenia, ERP amplitude frequency distribution analyses were also performed and compared among groups. However, these did not provide evidence of an outlying subgroup in any of the three groups. There were complex relationships between ERP component amplitudes and behavioral adjustment in adolescence but, in general, these did not distinguish high-risk and psychiatric control subjects from each other. There was no evidence of a relationship between deviant attentional functioning as measured in an earlier round of laboratory testing and ERP late component amplitude.

Toxocara canis infection of children: epidemiologic and neuropsychologic findings

Sera from 4,652 children whose blood was submitted to the New York City Department of Health for lead analysis were tested for antibodies to Toxocara canis using an enzyme-linked immunosorbent assay (ELISA). Standardized to the age distribution of the study population, T. canis seropositivity (inverse titers greater than or equal to 16) was 5.7 per cent in males and 5.1 per cent in females. T. canis antibody titers and lead exposures as measured by Centers for Disease Control lead classes were positively correlated. Children who were seropositive to T. canis (cases) were compared to seronegatives (controls) matched on age (+/- 6 months), sex, time-of-screening (+/- 3 months) and CDC lead class. Logistic regression analysis of 155 case-control pairs demonstrated elevated relative risks (RRs) for geophagia (RR = 3.14; 95% CI = 1.75, 5.64) and having had a litter of puppies in the home (RR = 5.22; 95% CI = 1.63, 16.71). Compared to controls, cases had increased eosinophil counts, serum immunoglobulin E concentrations, and anti-hemagglutinin-A titers. Small deficits in cases compared to controls were found in performance on several neuropsychological tests after adjustment for potential confounders including case-control differences in race, socioeconomic status, and current blood lead concentrations. The study thus confirmed that T. canis infection is common in urban children and suggested that infection may be associated with adverse neuropsychological effects.

The New York High-Risk Project: a followup report

The New York High-Risk Project began in 1971 as a prospective, longitudinal study of (1) children of one or two schizophrenic parents and (2) comparison groups of children whose parents had other or no psychiatric disorders. The former were examined because they were known to be at high risk--some 10-25 percent for children with one affected parent and 35-45 percent with two affected parents--for developing schizophrenia or schizophrenia spectrum disorders during adolescence or adulthood (Erlenmeyer-Kimling 1977; Gottesman and Shields 1982). Children of parents with affective disorders were included because we wished to determine whether variables that might differentiate the children of schizophrenic parents from the children of normal parents also differentiated them from children of parents with other psychiatric disorders. Major goals of the program were (1) identification of biological and behavioral indicators of a genetic liability to develop schizophrenia and (2) longitudinal followup of the subjects to assess the predictive validity and specificity of variables tentatively flagged as early indicators. Other goals have included evaluation of the developmental course of such variables and documentation of the history of the development of schizophrenic disorders.

High-risk research in schizophrenia: a summary of what has been learned

High-risk research on schizophrenia has been concerned chiefly with two types of issues: (1) description of background factors in the early lives of high-risk subjects; and (2) identification of biological variables that may be markers of the genetic liability to schizophrenic disorders. It is concluded that efforts to describe background factors have led to some conflicting results, have shown little evidence of specificity of the factors under study to risk for schizophrenia, and may not be generalizable to most individuals who develop schizophrenia. Results of research focusing on biological variables are summarized under the headings of attention and information processing (AIP), smooth pursuit eye movement (SPEM), neurological signs, electrodermal responding, event related potentials, and ventricular size. Of these, certain AIP and SPEM dysfunctions show substantial evidence of serving as biological markers, certain other AIP impairments are promising in this regard, electrodermal responsivity is not, and the other three categories present uncertain or conflicting results. Several methodological issues that have hampered the first generation of high-risk research are discussed.

Sustained attention in children at risk for schizophrenia: findings with two visual continuous performance tests in a new sample

In partial replication of an earlier study, 35 children at high risk for schizophrenia, 25 children at high risk for affective disorder, and 53 normal control children from a new sample of 7- to 12-year-old subjects were tested with two new visual continuous performance tests. Response levels and intrasubject variability were analyzed separately. Multivariate analyses on factor scores derived from response levels indicate that "groups" is a significant predictor for a factor reflecting discriminability (or sensitivity) for the more difficult of these tests but not for the less difficult one, and that high risk for schizophrenia is associated with lower performance. Factor scores and multiple regression analyses were used to dichotomize subjects as to whether or not they are low performance outliers. A significantly larger proportion of subjects from the high risk for schizophrenia group than from the control groups were low performance outliers. Among subjects that developed psychopathology in adolescence, subjects at high risk for schizophrenia were more likely to have contributed low performance outliers early during childhood.

Event-related potentials in children at risk for schizophrenia during two versions of the continuous performance test

Event-related potentials (ERPs) were recorded from children of schizophrenic parents, children of parents with affective disorders, and children of parents without a history of psychiatric illness. ERPs were elicited during two versions of the continuous performance test (CPT), which differed in their level of processing complexity. The data were recorded from electrodes located at midline frontal, central, parietal, and occipital scalp sites. Diagnostic assessments of the parents were performed using the Schedule for Affective Disorders and Schizophrenia-Lifetime Version and Research Diagnostic Criteria. Clinical assessments of the children were made with a modified version of the Global Assessment Scale. ERP amplitudes for six electrophysiological events were compared among groups for target and nontarget stimuli using analyses of variance of both factor score and baseline to peak measures. There was one isolated between-group finding: frontal negative slow wave recorded at FZ was of greater magnitude in the high risk (HR) than in either the psychiatric (PC) or normal control (NC) groups. Since only a small percentage of children at risk will eventually develop schizophrenia, ERP amplitude deviance and frequency distribution analyses were also performed and compared among groups. ERP component amplitudes did not distinguish the groups when each component was considered separately. Deviance analyses, using a combination of the amplitudes of the six ERP components, also did not provide evidence of a deviant subgroup within any of the three groups. There appeared to be no relationship between ERP component amplitudes and behavioral adjustment in adolescence. Some evidence of a relationship between deviant attentional functioning and ERP component amplitude was found, but the pattern of findings within the attentionally deviant HR subgroup was opposite to that found for the HR group as a whole and more consistent with the pattern found for the NC group.

Electrodermal recovery data on children of schizophrenic parents

Half-amplitude recovery of electodermal responses is compared in children of schizophrenic parents (high-risk subjects) and children of depressed or normal parents. The results are dissimilar to those reported by Mednick and colleagues on a Danish high-risk sample. No significant differences emerged among the three groups in our study. Recovery did not differ according to sex or severity of illness of the schizophrenic parent. Recoveries of high-risk subjects separated from their homes were not shorter than recoveries of subjects who remained home. Recovery time recorded in childhood was unrelated to global adjustment in adolescence.

Biobehavioral risk factors in children of schizophrenic parents

Research on risk factors for schizophrenia is reviewed with emphasis on children of schizophrenic parents. As children of schizophrenic parents are not representative of the majority of individuals who become schizophrenic, examination of variables such as those relating to home environment or parental characteristics in these children is not expected to contribute greatly to an understanding of risk for schizophrenia or to the search for early indicators of a genetic liability, whereas study of selected biobehavioral variables may do so. Four areas of biobehavioral functioning that have been examined in high-risk research are discussed. Three of these are considered to be compatible with the hypothesis of a neurointegrative defect underlying schizophrenia-proneness and to be promising for further research.

Auditory recognition memory in adolescents at risk for schizophrenia: report on a verbal continuous recognition task

As part of the New York High-Risk Project and in the context of a third round of testing, auditory short-term recognition memory for words and for consonant-vowel-consonant trigrams was measured in normal control adolescents (n = 53) and in adolescents at high risk for schizophrenia (n = 46). Differences in performance between the two groups are attributable to a lower initial memory strength on the part of the high-risk subjects, with trigrams showing larger differences than words. A subgroup of the high-risk subjects characterized by "clinical deviancy" showed, in addition, a (nonsignificant) increase in the rate of information loss from memory for trigrams.

Sustained attention in children at risk for schizophrenia. Report on a continuous performance test

A test of sustained attention (the Continuous Performance Test) was administered to a group of children at risk for the eventual manifestation of schizophrenia and to a group of "normal control" children. Differences in performance between the two groups were attributable to poorer discriminability on the part of the high-risk subjects.