Anthony J. Giuliano

Neurocognition in First-Episode Schizophrenia: A Meta-Analytic Review

Compromised neurocognition is a core feature of schizophrenia. Following Heinrichs and Zakzaniss (1998) seminal meta-analysis of middle-aged and predominantly chronic schizophrenia samples, the aim of this study is to provide a meta-analysis of neurocognitive findings from 47 studies of first-episode (FE) schizophrenia published through October 2007. The meta-analysis uses 43 separate samples of 2,204 FE patients with a mean age of 25.5 and 2,775 largely age- and gender-matched control participants. FE samples demonstrated medium-to-large impairments across 10 neurocognitive domains (mean effect sizes from -0.64 to -1.20). Findings indicate that impairments are reliably and broadly present by the FE, approach or match the degree of deficit shown in well-established illness, and are maximal in immediate verbal memory and processing speed. Larger IQ impairments in the FE compared to the premorbid period, but comparable to later phases of illness suggests deterioration between premorbid and FE phases followed by deficit stability at the group level. Considerable heterogeneity of effect sizes across studies, however, underscores variability in manifestations of the illness and a need for improved reporting of sample characteristics to support moderator variable analyses.

Premorbid IQ in Schizophrenia: A Meta-Analytic Review

OBJECTIVE Over the past three decades, there have been significant changes in the diagnostic criteria for schizophrenia as well as changes in measurement of IQ. The last quantitative review of the literature on premorbid IQ in schizophrenia was published more than two decades ago. Since that time, there have been many published studies of data sets pertaining to this issue. The purpose of the present review was to provide an updated meta-analysis of premorbid IQ in individuals who later develop schizophrenia. METHOD The authors performed a systematic literature search, which yielded 18 studies that met criteria for the meta-analysis. Inclusion criteria were 1) premorbid psychometric measures of IQ in subjects who were later diagnosed with schizophrenia, schizoaffective disorder, or schizophreniform disorder, 2) similar comparison data, and 3) sufficient data for calculation of an effect size. The analogue to the analysis of variance method was used to model between-study variance due to key study-design features. RESULTS Overall, schizophrenia samples demonstrated a reliable, medium-sized impairment in premorbid IQ. The heterogeneity of effect sizes was minimal and almost exclusively the result of one study. Methodological differences, such as diagnostic criteria, type of IQ measure, sample ascertainment, and age at premorbid testing, contributed minimally to the effect size variance. A cross-sectional analysis of all studies by age and a descriptive review of studies that used repeated measures of IQ in a single sample did not support the presence of a relative decline in IQ during the premorbid period in individuals with schizophrenia. However, all studies with pre- and post-onset testing within the same sample suggested that a significant decline in the IQ of individuals with schizophrenia, relative to comparison subjects, was associated with the onset of frank psychosis. CONCLUSIONS Years before the onset of psychotic symptoms, individuals with schizophrenia, as a group, demonstrate mean IQ scores approximately one-half of a standard deviation below that of healthy comparison subjects.

Neuropsychological Profiles in Individuals at Clinical High Risk for Psychosis: Relationship to Psychosis and Intelligence

BACKGROUND Characterizing neuropsychological (NP) functioning of individuals at clinical high risk (CHR) for psychosis may be useful for prediction of psychosis and understanding functional outcome. The degree to which NP impairments are associated with general cognitive ability and/or later emergence of full psychosis in CHR samples requires study with well-matched controls. METHODS We assessed NP functioning across eight cognitive domains in a sample of 73 CHR youth, 13 of whom developed psychotic-level symptoms after baseline assessment, and 34 healthy comparison (HC) subjects. Groups were matched on age, sex, ethnicity, handedness, subject and parent grade attainment, and median family income, and were comparable on WRAT-3 Reading, an estimate of premorbid IQ. Profile analysis was used to examine group differences and the role of IQ in profile shape. RESULTS The CHR sample demonstrated a significant difference in overall magnitude of NP impairment but only a small and nearly significant difference in profile shape, primarily due to a large impairment in olfactory identification. Individuals who subsequently developed psychotic-level symptoms demonstrated large impairments in verbal IQ, verbal memory and olfactory identification comparable in magnitude to first episode samples. CONCLUSIONS CHR status may be associated with moderate generalized cognitive impairments marked by some degree of selective impairment in olfaction and verbal memory. Impairments were greatest in those who later developed psychotic symptoms. Future study of olfaction in CHR samples may enhance early detection and specification of neurodevelopmental mechanisms of risk.

Magnetic Resonance Imaging Studies in Early-Onset Bipolar Disorder: A Critical Review

Background: Neuroimaging studies of early‐onset bipolar disorder (BD) are important in order to establish a fuller understanding of the underlying pathophysiology of the illness. The advantages of studying BD in children and adolescents include the relative absence of some confounds present in adult‐onset research, such as lengthy duration of illness and exposure to treatments, greater number of mood episodes, and the presence of substance abuse or dependence. Finally, studying youths with the disorder may enhance our knowledge about the neural mechanisms of affective dysregulation and may specifically elucidate whether there are abnormalities that are unique to the early‐onset form of the illness. Methods: PubMed was used to identify peer‐reviewed publications from the past 15 years (January 1990 to January 2005) that used brain‐imaging techniques (anatomic, functional, and biochemical) to research early‐onset BD. Results: Eleven studies using anatomic magnetic resonance imaging (MRI), seven using magnetic resonance spectroscopy (MRS), and two using functional MRI (fMRI) were identified. Structural abnormalities were reported in total cerebral, white matter, superior temporal gyrus, putamen, thalamus, amygdala, and hippocampal volumes. Deficits in cortical gray matter were also reported. Using MRS, abnormalities were reported in the dorsolateral prefrontal cortex, anterior cingulate, and basal ganglia. One fMRI study found increased activation in the putamen and thalamus of BD youths compared to controls, and a second found abnormal prefrontal‐subcortical activation in familial pediatric BD. Conclusion: Published MRI studies of early‐onset BD are few. Nonetheless, extant data implicate abnormalities in brain regions thought to regulate mood and cognition. Synthesis of the findings into an overall model of anatomic and functional disruption is difficult due to the methodological variations among studies and the limitations of individual studies, such as the use of small sample sizes, the heterogeneity of sample characteristics, and the wide range of brain structures selected for analysis. Recommendations are offered to guide future research. It will be important for future studies to reproduce prior findings and determine which findings are unique to early‐onset BD, relative to adult‐onset illness. In addition, studies will need to establish the extent to which early‐onset BD may overlap with comorbid disruptive, mood, anxiety, or psychotic disorders. (HARV REV PSYCHIATRY 2005;13:125–140.)

Group and site differences on the California Verbal Learning Test in persons with schizophrenia and their first-degree relatives: findings from the Consortium on the Genetics of Schizophrenia (COGS).

Genetic studies of schizophrenia focus increasingly on putative endophenotypes because their genetic etiology may be simpler than clinical diagnosis. The Consortium on the Genetics of Schizophrenia (COGS), a multisite family study, aims to identify the genetic basis of several endophenotypes including verbal declarative memory (VDM), a neurocognitive function that shows robust impairment in schizophrenia. We present data on one type of measure of VDM, the California Verbal Learning Test, Second Edition (CVLT-II), in schizophrenia probands (n=305), their full biological siblings (n=449) and parents (n=232), and in community comparison subjects (CCS; n=509) across seven sites. Probands performed more poorly on each of five CVLT-II measures compared to related sibling and parent groups and CCS. Siblings and parents performed significantly worse than CCS on one measure (Discriminability), but with smaller effect sizes and less impairment than observed previously. The results raise questions about the homogeneity of VDM as an endophenotype, about methodological issues related to sampling, and about psychometric issues that impact the utility of the CVLT for detecting VDM deficits in nonpsychotic relatives of persons with schizophrenia.

Age-related changes in the corpus callosum in early-onset bipolar disorder assessed using volumetric and cross-sectional measurements

Corpus callosum (CC) area abnormalities have been reported in magnetic resonance imaging (MRI) studies of adults and youths with bipolar disorder (BPD), suggesting interhemispheric communication may be abnormal in BPD and may be present early in the course of illness and affect normal neuromaturation of this structure throughout the lifecycle. Neuroimaging scans from 44 youths with DSM-IV BPD and 22 healthy controls (HC) were analyzed using cross-sectional area measurements and a novel method of volumetric parcellation. Univariate analyses of variance were conducted on CC subregions using both volume and traditional area measurements. Youths with BPD had smaller middle and posterior callosal regions, and reduced typical age-related increases in CC size. The cross-sectional area and novel volumetric methodologies resulted in similar findings. Future longitudinal assessments of CC development would track the evolution of callosal abnormalities in youths with BPD and allow exploration of the functional significance of these findings.

Coaching and the Ability to Simulate Mild Traumatic Brain Injury Symptoms

This study assessed the ability of normal controls to simulate mild traumatic brain injury with or without the aid of general simulation strategies. An additional purpose was to evaluate the relative ability of four tests of performance motivation or malingering to discriminate among the five groups in this study. Twenty-one patients with documented mild traumatic brain injury (TBI) and 112 undergraduate students were administered the measures of symptom validity in randomized order with instructions either to perform to the best of their ability or to fake believable deficits. Students asked to malinger were either given instructions to do so with no guidance (No Strategies group or NS), a minimal level of guidance (Only Strategies group or OS) or a moderate level of guidance (Strategies and Example or SE). Students given simulation strategies (OS and SE groups) were able to match performance of the TBI group in only those instances when TBI performance was similar to the normal comparison group. When TBI performance fell considerably below the normal comparison group, naïve simulators (NS group) best approximated TBI performance. The degree of variability in the classification success of the four tests underscored the necessity of combining detection methods, as well as the need to develop new tests more resistant to attempts to feign brain injury.

Auditory working memory impairments in individuals at familial high risk for schizophrenia.

OBJECTIVES The search for predictors of schizophrenia has accelerated with a growing focus on early intervention and prevention of psychotic illness. Studying nonpsychotic relatives of individuals with schizophrenia enables identification of markers of vulnerability for the illness independent of confounds associated with psychosis. The goal of these studies was to develop new auditory continuous performance tests (ACPTs) and evaluate their effects in individuals with schizophrenia and their relatives. METHODS We carried out two studies of auditory vigilance with tasks involving working memory (WM) and interference control with increasing levels of cognitive load to discern the information-processing vulnerabilities in a sample of schizophrenia patients, and two samples of nonpsychotic relatives of individuals with schizophrenia and controls. Study 1 assessed adults (mean age = 41), and Study 2 assessed teenagers and young adults age 13-25 (M = 19). RESULTS Patients with schizophrenia were impaired on all five versions of the ACPTs, whereas relatives were impaired only on WM tasks, particularly the two interference tasks that maximize cognitive load. Across all groups, the interference tasks were more difficult to perform than the other tasks. Schizophrenia patients performed worse than relatives, who performed worse than controls. For patients, the effect sizes were large (Cohens d = 1.5), whereas for relatives they were moderate (d = ~0.40-0.50). There was no age by group interaction in the relatives-control comparison except for participants <31 years of age. CONCLUSIONS Novel WM tasks that manipulate cognitive load and interference control index an important component of the vulnerability to schizophrenia.

Change in neuropsychological functioning over one year in youth at clinical high risk for psychosis.

Schizophrenia and related psychotic disorders are associated with significant neuropsychological (NP) impairments. Yet the onset and developmental evolution of these impairments remains incompletely characterized. This study examined NP functioning over one year in a sample of youth at clinical high risk (CHR) for psychosis participating in a treatment study. We assessed functioning across six cognitive domains at two time points in a sample of 53 CHR and 32 healthy comparison (HC) subjects. Linear regression of HC one-year scores was used to predict one-year performance for CHR from baseline scores and relevant demographic variables. We used raw scores and MANOVAs of the standardized residuals to test for progressive impairment over time. NP functioning of CHR at one year fell significantly below predicted levels. Effects were largest and most consistent for a failure of normative improvement on tests of executive function. CHR who reached the highest positive symptom rating (6, severe and psychotic) on the Structured Interview of Prodromal Syndromes after the baseline assessment (n = 10/53) demonstrated a particularly large (d = -1.89), although non-significant, discrepancy between observed and predicted one-year verbal memory test performance. Findings suggest that, although much of the cognitive impairment associated with psychosis is present prior to the full expression of the psychotic syndrome, some progressive NP impairments may accompany risk for psychosis and be greatest for those who develop psychotic level symptoms.

A functional MRI study of working memory in adolescents and young adults at genetic risk for bipolar disorder: preliminary findings

Thermenos HW, Makris N, Whitfield‐Gabrieli S, Brown AB, Giuliano AJ, Lee EH, Faraone SV, Tsuang MT, Seidman LJ. A functional MRI study of working memory in adolescents and young adults at genetic risk for bipolar disorder: preliminary findings.
Bipolar Disord 2011: 13: 272–286.