[Show abstract][Hide abstract] ABSTRACT: Numerous studies have implicated the hippocampus and prefrontal cortex in schizophrenia. However, precisely which subregions of the hippocampus and prefrontal cortex are abnormal remain unknown. Our study goal was to investigate the structure of the anterior hippocampus, posterior hippocampus, dorsolateral prefrontal cortex (DLPFC), and orbitofrontal cortex (OFC) simultaneously in thirty-eight patients with schizophrenia and twenty-nine controls to determine which of these subregions are abnormal in schizophrenia. As an exploratory study goal, we investigated the relation of neurocognition to brain structure in schizophrenia patients.
We generated detailed structural magnetic resonance imaging data and compared hippocampal and prefrontal subregional structural brain volumes between schizophrenia and control groups. We obtained a neurocognitive test battery in schizophrenia patients and studied the association of abnormal brain structures to neurocognition.
Structural brain abnormalities were pinpointed to the left anterior hippocampus and left OFC in schizophrenia patients, which were both significantly reduced in volume. The DLPFC and posterior hippocampus, though numerically decreased in volume, were not significantly decreased. Anterior hippocampal volumes were more strongly associated with OFC volumes in schizophrenia patients compared to controls. By contrast, DLPFC volume was unrelated to anterior or posterior hippocampal volume. Both the anterior hippocampus and OFC were independently related to cognitive abnormalities common in schizophrenia, including indices of verbal, language, and executive functions. The DLPFC and posterior hippocampal volumes were unrelated to cognitive measures.
These findings highlight related abnormalities of the anterior hippocampus and OFC in schizophrenia, which may shed light on the pathophysiology of the disorder.
Schizophrenia Research 09/2009; 114(1-3):110-8. · 4.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An expanding database supports the notion that the deficit syndrome (DS) is a discrete condition within schizophrenia and recent data argues that Smell Identification Deficits (SID) may have a primary relationship with its pathophysiology. If so, then the relationship of University of Pennsylvania Smell Identification Test (UPSIT) scores with other neurocognitive measures in DS patients may point to the neural substrate of the deficit syndrome.
We examined the relationship of UPSIT scores and Wechsler Adult Intelligence Scale-Revised (WAIS-R) performance in 46 DSM-IV schizophrenia patients. The Schedule for the Deficit Syndrome (SDS) interview was used to subgroup the sample into 13 DS and 33 nondeficit syndrome (NDS) patients.
DS and NDS groups had similar mean ages, age of onset, and GAF scores, but DS patients had fewer years of education. DS and NDS patients also did not differ in full scale, verbal or performance IQ or in any WAIS-R subtest. However, UPSIT scores were significantly worse in the DS patients, most of whom met criteria for a clinically meaningful olfactory impairment. In DS patients, UPSIT scores were significantly correlated with Performance IQ, Block Design, and Object Assembly, all of which are associated with complex visual-motor organizational function thought to be mediated by parietal circuitry. UPSIT scores in NDS patients were significantly related with Vocabulary, Similarities, and Digit Symbol subtests, which are indicative of verbal functioning.
These preliminary data support previous findings suggesting that in addition to frontal neuropsychological abnormalities, DS patients may have greater performance impairments on tasks associated with parietal functioning. Our findings furthermore suggest that the parietal circuitry may be a conspicuous substrate for impaired odor identification ability in these patients. The lesser abnormalities in UPSIT ability in NDS patients may be attributed to verbal ability. These data are preliminary and further investigations with larger samples are needed to support our findings.
Schizophrenia Research 08/2004; 69(1):55-65. · 4.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous research has established a relationship between smell identification deficits (SID) and particular aspects of cognitive function among patients with schizophrenia.
To expand the extant literature, we examined the relationship between SID and the Trail Making Test to determine if processing speed is related to SID.
Our sample included 60 inpatients from the New York State Psychiatric Institute's Schizophrenia Research Unit. We considered age, deficit syndrome, verbal intelligence quotient, and education in our analyses due to their documented relationship to smell identification ability.
Trails A errors and Trails A seconds accounted for a significant amount of the variance in University of Pennsylvania Smell Identification Test scores in a regression analysis (R2=.10, P=.008 and R2=.05, P=.04).
Linking neurocognition to smell identification deficits may prove to be an essential marker for schizophrenia research.
[Show abstract][Hide abstract] ABSTRACT: Evidence is accumulating that smell identification deficits (SID) and social dysfunction in schizophrenia may share a common pathophysiology. While most schizophrenia studies utilize the lengthy 40-item University of Pennsylvania Smell Identification Test (UPSIT) to assess smell identification ability, a brief 12-item smell identification test (B-SIT) has recently been constructed as a culturally neutral substitute for the UPSIT. By selecting the 12 items of the UPSIT from which the B-SIT was originally derived, we constructed a proxy for the B-SIT and compared the performance of 83 patients with schizophrenia to 69 normal subjects. We examined select properties of the B-SIT proxy in relation to the UPSIT to determine its efficacy for use in psychiatric populations. We considered the sensitivity of the B-SIT proxy and evaluated a cutoff score for identifying deficit syndrome schizophrenia (DS). The UPSIT and B-SIT proxy were significantly related in the patients (n=83, r=0.85, P=0.01) and in comparison subjects (n=69, r=0.83, P=0.01), and both measures similarly distinguished DS from non-deficit syndrome (non-DS) patients. The results of this study support the utility of the B-SIT for schizophrenia research and highlight the robustness of the relationship between SID and social dysfunction in schizophrenia.
Psychiatry Research 10/2003; 120(2):155-64. · 2.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Poor insight into illness is a common feature of bipolar disorder and one that is associated with poor clinical outcome. Empirical studies of illness awareness in this population are relatively scarce with the majority of studies being published over the previous decade. The study reported here sought to replicate previous report findings that bipolar patients frequently show high levels of poor insight into having an illness. We also wanted to examine whether group differences in insight exist among bipolar manic, mixed and unipolar depressed patients with psychotic features.
A cohort of 147 inpatients with DSM-III-R bipolar disorder and 30 with unipolar depression with psychotic features, were evaluated in the week prior to discharge using the Structured Clinical Interview for DSM-III-R-Patient Edition (SCID-P), the Brief Psychiatric Rating Scale (BPRS) and the Scale to assess Unawareness of Mental Disorder (SUMD).
Insight into specific aspects of the illness was related to the polarity of mood episode: patients with mania showed significantly poorer insight compared with those with mixed mania, bipolar depression and unipolar depression. A linear regression analysis using SUMD score as the dependent variable and symptoms of mania as the independent variable found that specific manic symptoms did not account for level of insight. Similar results were obtained when the mean insight scores of patients with and without grandiosity were contrasted.
We hypothesize that the lack of association between level of insight and total number of manic symptoms or with specific manic symptoms may be related to the persistence of subsyndromal symptoms in patients remitting from a manic episode.
[Show abstract][Hide abstract] ABSTRACT: Methodological issues involved in evaluating insight into illness and the ongoing struggle within the field to agree on terminology and methodology are discussed and a comparison is offered of different research instruments that have been developed in recent years. The following 5 methods of measuring insight are considered: clinical descriptions of free responses, clinical free responses to a controlled stimulus, systematized scoring of free responses, systematized scoring of responses to a standard stimulus, and the multiple choice method. Methods of insight assessment are compared with special focus on the psychometric strengths and weaknesses of each. The data reviewed show that patients' subjective experiences are a rich and valuable source of information and that interventions or attempts to improve insight should be targeted with specific goals in mind. (PsycINFO Database Record (c) 2012 APA, all rights reserved)