The dimensional symptom structure of schizophrenia and its association with temperament and character

Recent studies suggest that personality may influence symptom expression and social functioning in schizophrenia. This study investigated the relationships between personality and symptom dimensions in schizophrenia patients. Fifty-two schizophrenia patients and 25 five healthy subjects were assessed using the Temperament and Character Inventory (TCI). The patients were also assessed for positive and negative symptoms using SAPS and SANS and scored according to Andreasen's (1995: Andreasen, N.C., Arndt, S., Alliger, R., Miller, D., Flaum, M. 1995. Symptoms of schizophrenia. Methods, meanings, and mechanisms. Arch. Gen. Psychiatry, 52, 341-351) classical three dimensional model and by the five dimensional model of Toomey et al. (1997: Toomey, R., Kremen, W.S., Simpson J.C., Samson, J.A., Seidman, L.J., Lyons, M.J., Faraone, S.V., Tsuang, M.T. 1997. Revisiting the factor structure for positive and negative symptoms: evidence from a large heterogeneous group of psychiatric patients. Am. J. Psychiatry, 154, 371-377). Comparisons between patients and controls revealed significant differences on various TCI scores consistent with a global disorganization of personality in schizophrenia involving both basic neurophysiological and potentially genetically determined traits (i.e. temperament) and developmental aspects of personality (i.e. character). Correlation analysis showed distinct associations between symptoms and personality dimensions. The results suggest that the negative and disorganized dimensions of schizophrenia are related temperamental factors, whereas the psychotic symptoms are more related to characterological abnormalities. The observed patterns of associations also underline the heterogeneity of the classical negative and positive dimensions of schizophrenia.     

Personality in schizophrenia assessed with the Temperament and Character Inventory (TCI)

The Temperament and Character Inventory (TCI) is a well-established self-report questionnaire measuring four temperament and three character dimensions. However, surprisingly few studies have used it to examine the personality of patients with schizophrenia, and none in Japan. Moreover, possible gender differences in personality among patients with schizophrenia have not been well documented. We administered the TCI to 86 Japanese patients with schizophrenia and 115 age- and gender-matched healthy controls to characterize personality traits in patients with schizophrenia and to examine their relationships with clinical variables, particularly gender and symptoms. Compared with controls, patients demonstrated significantly lower novelty seeking, reward dependence, self-directedness and cooperativeness, and higher harm avoidance and self-transcendence. Male patients showed even more pronounced personality alteration than female patients when both of them were compared with healthy people. Personality dimensions were moderately correlated with symptom dimensions assessed by the Positive and Negative Syndrome Scale (PANSS). These results, together with prior findings in several other countries, suggest that schizophrenia patients have a unique personality profile which appears to be present across cultures and that the greater alteration of personality in schizophrenia males might be related to their poorer social and community functioning.     

Relationships between season of birth, schizotypy, temperament, character and neurocognition in a non-clinical population

While schizophrenia has been associated with a slight excess of winter/early spring birth, it is unclear whether there is such an association in relation to schizotypal personality traits. Season of birth has also been reported to relate to temperament and character personality dimensions and cognitive functioning. Moreover, non-clinical schizotypy has been shown to be associated with mild cognitive impairment, although its precise nature is yet to be elucidated. Here we examined the relationships between season of birth, schizotypal traits, temperament and character, and cognitive function. Four hundred and fifty-one healthy adults completed the Schizotypal Personality Questionnaire (SPQ). The Temperament and Character Inventory (TCI) and a neuropsychological test battery consisting of full versions of the Wechsler Memory Scale-Revised and the Wechsler Adult Intelligence Scale-Revised, and the Wisconsin Card Sorting Test, were also administered to most of the participants. The total SPQ score of those born in winter was significantly higher than that of the remaining participants. Season of birth was not significantly associated with any of the TCI dimensions or cognitive test results. Significant but mild relationships between higher SPQ scores and lower scores on some aspects of IQ were observed. These results support the notion that schizotypy and schizophrenia are neurodevelopmental conditions on the same continuum.     

Personality differences in schizophrenia are related to performance on neuropsychological tasks

Altered cognition and personality appear to emerge in tandem and adversely affect outcome in schizophrenia, yet little research has been done to determine whether these are related or independent domains. In this study, the relationship between the Big Five personality traits--neuroticism, extraversion, openness, agreeableness, conscientiousness--and cognitive and motor performance in outpatients with chronic, clinically stable schizophrenia (N = 30) and age-matched healthy comparison subjects (N = 45) was examined. Subjects completed tests of attention, executive and motor functions, and the NEO-Five Factor Personality Inventory. Patients scored significantly higher on neuroticism and lower on extraversion and agreeableness, but after variance due to neuropsychological performance was statistically removed from NEO scale scores, personality dimensions and profiles no longer differed between groups. Neuropsychological performance and demographic variables, but not diagnosis, uniquely accounted for statistically significant amounts of personality variance, and neuropsychological task performance was correlated with personality dimensions in both patients and comparison subjects. These cross-sectional data provide preliminary evidence that personality dysfunction in schizophrenia may be mediated by disease-related changes in cognitive operations, or the neural processes underlying them. Longitudinal studies utilizing more comprehensive measures of neurocognitive performance are needed to define further the relationship between neuropsychological function and personality in schizophrenia.     

Temperament and character in violent schizophrenic patients

Preliminary evidence shows that personality traits are important in determining violent behavior in schizophrenia. As only some patients with schizophrenia show a greater risk for violence, this risk may therefore be considered as dynamic, varying as a function of the extent to which certain personality dimensions are present and the degree to which environmental events moderate or exacerbate their expression. OBJECTIVE: To compare temperament and character dimensions between violent and non-violent schizophrenic patients and to determine which temperament and character dimensions are predictors of violent behavior in schizophrenia. METHOD: We recruited 102 schizophrenic patients without concomitant substance abuse 4 months prior to the assessment. Diagnoses were based on the SCID-I. Personality dimensions were assessed with the Temperament and Character Inventory and violent behaviors with the Overt Aggression Scale. RESULTS: Higher levels of the temperament dimension novelty seeking and a lower cooperativeness, as a character dimension, were risk factors for violent behavior in schizophrenic patients. DISCUSSION: Our data indicate that schizophrenic patients will show a greater risk for violence according to certain personality configurations and the degree to which environmental events moderate or exacerbate their expression.     

Personality dimensions in first-episode psychoses

OBJECTIVE: The authors compared the patterns and specificity of premorbid personality dimensions in first-episode schizophrenia patients with those in patients with first-episode nonschizophrenia psychoses and healthy comparison subjects. METHOD: A series of 63 patients with first-episode schizophrenia and related psychotic disorders, 34 patients with first-episode nonschizophrenia psychoses, and 77 healthy comparison subjects were assessed with the Personality Disorder Evaluation, a semistructured interview schedule that measures personality dimensions. RESULTS: Cluster A as well as cluster C dimensional scores-in particular, the avoidant personality score-were higher for the schizophrenia patients, and cluster B dimensional scores were higher for the patients with nonschizophrenia psychoses. Cluster C dimensional scores, particularly the avoidant personality score, were highly intercorrelated with all cluster A dimensional scores. CONCLUSIONS: The observed association between avoidant personality and schizophrenia supports the recent literature on the comorbidity of nonspectrum personality disorders in schizophrenia. This association may be related to shared neurodevelopmentally mediated impairments in social cognition in schizophrenia and some cluster C personality dimensions.     

Temperament and character in individuals at ultra-high risk for psychosis and with first-episode schizophrenia: Associations with psychopathology,psychosocial functioning,and aspects of psychological health

Objective

The psychobiological model of temperament and character indicates that personality traits are heritable and, during development, constantly influence one’s susceptibility to schizophrenia. Our objective was to evaluate temperament and character in subjects at ultra-high risk (UHR) for psychosis and individuals with first-episode schizophrenia.

Methods

UHR for psychosis subjects (n = 50), first-episode schizophrenia patients (n = 33), and normal controls (n = 120) were compared on temperament and character dimensions, and correlation analysis of each personality dimension with psychopathologies, global and social functioning, and self-esteem. General and social self-efficacy reports were conducted. UHR subjects were followed-up for 24 months and the baseline personality dimensions were compared between the converted and non-converted groups.

Results

Both clinical groups showed abnormal personality traits in terms of temperament (higher harm avoidance, lower reward dependence and persistence) and character (lower self-directedness and cooperativeness). Psychosocial functioning and psychological health components were found to be correlated with some personality dimensions. The conversion rate of overt psychotic disorder was 25.0% at the 24-month follow-up. Baseline cooperativeness dimension was a significant predictive dimension for conversion into overt psychosis in the UHR group during the follow-up period.

Conclusion

Patients with first episode schizophrenia have a pervasively altered personality profile from normal controls. More importantly, this altered personality profile already emerged in putative prodromal, UHR individuals. The present findings indicate that certain personality traits can play a protective or vulnerable role in developing schizophrenia.     

Longitudinal alterations of executive function in non-psychotic adolescents at familial risk for schizophrenia

Genetic diathesis to schizophrenia may involve alterations of adolescent neurodevelopment manifesting as cognitive deficits. Brain regions mediating executive function (fronto-striatal circuits) develop during adolescence while those supporting elementary aspects of attention (e.g. sustained focused attention) have a more protracted maturation beginning in childhood. We hence predicted that adolescents at risk for schizophrenia would show a failure of normal maturation of executive function. We prospectively assessed 18 offspring and 6 siblings of schizophrenia patients (HR) and 28 healthy controls at baseline, year-1 and year-2 follow-up using the Continuous Performance Test [visual-d′] and Wisconsin Card Sort Test (WCST). Perseverative errors on the WCST in HR remained stable but decreased in controls over the follow-up (study-group by assessment–time interaction, p = 0.01, controlling for IQ). No significant study-group by assessment-time interactions were seen for sustained attentional performance. HR may not improve while healthy subjects progressively improve on executive function during adolescence and early adulthood. Our results suggest an altered maturational trajectory of executive function during adolescence in individuals at familial risk for schizophrenia.     

Temperament, character, and quality of life in patients with schizophrenia and their first-degree relatives

The aim of this study was to investigate the associations between the temperament, character dimensions, and quality of life (QOL) of patients with schizophrenia; their first-degree, nonaffected relatives; and healthy control subjects. One hundred twenty patients, the same number of first-degree relatives, and the same number of control subjects were assessed using the Temperament and Character Inventory and the Quality of Life Enjoyment and Satisfaction Questionnaire. Patients were also assessed using the Positive and Negative Syndrome Scale. Patients and relatives had a significantly lower QOL than control subjects, controlled for temperament and character dimensions. Patients scored significantly higher than control subjects in harm avoidance and self-transcendence and lower in novelty seeking and self-directedness. First-degree relatives had lower results for novelty seeking and scored higher on self-transcendence than control subjects. Harm avoidance, self-directedness, and self-transcendence were the dimensions of Temperament and Character Inventory shown to be the most significant predictors of QOL. Psychopathology and age were also significant predictors of QOL. Our understanding of an individual patient's QOL must include personality evaluation.     

Cognitive and prepulse inhibition deficits in psychometrically high schizotypal subjects in the general population: relevance to schizophrenia research

Schizophrenia and schizotypal personality disorder share common clinical profiles, neurobiological and genetic substrates along with Prepulse Inhibition and cognitive deficits; among those, executive, attention, and memory dysfunctions are more consistent. Schizotypy is considered to be a non-specific "psychosis-proneness," and understanding the relationship between schizotypal traits and cognitive function in the general population is a promising approach for endophenotypic research in schizophrenia spectrum disorders. In this review, findings for executive function, attention, memory, and Prepulse Inhibition impairments in psychometrically defined schizotypal subjects have been summarized and compared to schizophrenia patients and their unaffected first-degree relatives. Cognitive flexibility, sustained attention, working memory, and Prepulse Inhibition impairments were consistently reported in high schizotypal subjects in accordance to schizophrenia patients. Genetic studies assessing the effects of various candidate gene polymorphisms in schizotypal traits and cognitive function are promising, further supporting a polygenic mode of inheritance. The implications of the findings, methodological issues, and suggestions for future research are discussed. (JINS, 2012, 18, 1-14).     

Predicting domain-specific insight of schizophrenia patients from symptomatology, multiple neurocognitive functions, and personality related traits

This study examines the contribution of various neurocognitive functions, clinical characteristics, and personality traits to the prediction of three insight dimensions. Clinically stable schizophrenia patients (n=107) residing in the community were evaluated using the Positive and Negative Syndrome Scale, the Scale for the Assessment of Unawareness of Mental Disorder, and a comprehensive battery of instruments to measure personality related variables and neurocognitive functioning. Step-wise multivariate regression analysis indicates significant association of variability in insight dimensions with neurocognitive functioning (20-41%), personality related traits (8-18% temperament factors, 4-7% self-constructs, 10-14% coping styles), severity of symptoms (about 7%), illness duration (6%), and education (about 5%). Poor insight was attributed to impairment in visual and movement skills, sustained attention, executive functions, intensity of autistic preoccupations and positive symptoms, as well as increased novelty seeking behavior, task and emotion oriented coping styles, better self-esteem, self-efficacy, and higher education. Better awareness was related to better performance of neurocognitive tasks, reward dependence behavior, avoidant coping style, and longer illness duration. Aside from common indicators for the various insight dimensions, we defined specific indicators for each insight dimension. Thus, insight dimensions in schizophrenia patients residing in the community were attributed to neurocognitive and personality related factors rather than to psychopathological symptoms. The findings enable better understanding of the multifactorial nature of insight and highlight targets for more effective intervention and rehabilitation.     

Premorbid personality in psychoses

This study aimed to establish correlates of the dimensions of schizophrenia in the premorbid personality traits of patients. A sample of 112 patients of relatively recent illness onset who were admitted for a psychotic episode were assessed with a semistructured interview for schizophrenia. Positive and negative symptoms were evaluated with the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms at the time of hospital discharge; positive, negative, and disorganization scores were obtained from these scales. Premorbid personality was assessed blindly through a partially modified version of the Personality Assessment Schedule using interviews with the parents or a close relative. Schizoid traits were significantly associated with negative and positive dimensions. Sociopathic traits were related to the disorganization dimension. Trends toward significance were obtained between passive-dependent traits and the negative and disorganization dimensions, and between the schizotypal dimension and the positive dimension. Partial correlational analyses were used to control for the effect of the remaining personality dimensions on the above relationships. Schizoid premorbid traits were still significantly related to the negative dimension but to a lesser degree to the disorganization and positive dimensions. The association between sociopathic premorbid traits and the disorganization dimension remained significant. These results suggest the preexistence of a three-dimensional structure predisposing to psychoses within the premorbid personality; this structure is more evident in patients with short illness duration.     

A neuropsychological investigation into violence and mental illness

Previous research has reported cognitive impairment in patients with schizophrenia and antisocial personality disorder (APD), the two psychiatric illnesses most implicated in violent behaviour. Previous studies have focused on either group exclusively, and have been criticized for procedural inadequacies and sample heterogeneity. The authors investigated and compared neuropsychological profiles of individuals with APD and violent and nonviolent individuals with schizophrenia in a single investigation. The study involved four groups of subjects: (i) individuals with a history of serious violence and a diagnosis of APD, (ii) individuals with a history of violence and schizophrenia, (iii) individuals with schizophrenia without a history of violent behaviour and (iv) healthy control subjects. All study groups were compared on a neuropsychological battery designed to assess general intellectual function, executive function, attention, and processing speed. Cognitive deficits were more widespread among individuals with schizophrenia regardless of history of violence, compared with those with APD. Significant impairment in patients with APD was limited to processing speed. Violent individuals with schizophrenia demonstrated poorer performance than their nonviolent schizophrenia peers on a measure of executive function. Different cognitive impairments are manifested by individuals with APD and schizophrenia with violent behaviours, suggesting differences in underlying pathology. Furthermore, cognitive impairment appears to be more a feature of schizophrenia than of violent behaviour, although there is evidence that a combination of schizophrenia and violent behaviour is associated with greater cognitive deficits.     

Using Implicit Association Tests for the assessment of implicit personality self-concepts of extraversion and neuroticism in schizophrenia

There is evidence from research based on self-report personality measures that schizophrenia patients tend to be lower in extraversion and higher in neuroticism than healthy individuals. Self-report personality measures assess aspects of the explicit self-concept. The Implicit Association Test (IAT) has been developed to assess aspects of implicit cognition such as implicit attitudes and implicit personality traits. The present study was conducted to investigate the applicability and reliability of the IAT in schizophrenia patients and test whether they differ from healthy individuals on implicitly measured extraversion and neuroticism. The IAT and the NEO-FFI were administered as implicit and explicit measures of extraversion and neuroticism to 34 schizophrenia patients and 45 healthy subjects. For all IAT scores satisfactory to good reliabilities were observed in the patient sample. In both study groups, IAT scores were not related to NEO-FFI scores. Schizophrenia patients were lower in implicit and explicit extraversion and higher in implicit and explicit neuroticism than healthy individuals. Our data show that the IAT can be reliably applied to schizophrenia patients and suggest that they differ from healthy individuals not only in their conscious representation but also in their implicit representation of the self with regard to neuroticism and extraversion-related characteristics.     

Covariance of personality, neurocognition, and schizophrenia spectrum traits in the community.

Clinical researchers have observed in relatives of schizophrenic individuals abnormal personality traits resembling the psychopathology of schizophrenia. Further similarities have been observed in correlations between measures of brain function, including attention and executive abilities, and these personality psychopathologies. However, two methodologic factors might account for the covariation of these 'schizophrenia spectrum' personality traits and measures of brain function. Clinical selection bias (Berkson's bias) might result in subjects with overlapping conditions being more likely to be studied, and normal personality attributes could affect performance on neurobehavioral tasks. This study investigated relationships between neurobehavioral correlates of schizophrenia, clinical schizophrenia spectrum personality traits, and normal personality dimensions in the five-factor model of personality. To avoid Berkson's bias, subjects expected to have a high probability of spectrum traits were recruited from the Baltimore Epidemiologic Catchment Area Survey community sample. About 40% of the sample were found to have DSM-IIIR Schizotypal, Schizoid, or Paranoid Personality Traits or Disorders. Schizophrenia Spectrum traits showed significant associations with personality dimensions of the five factor model, particularly Openness to Experience and Neuroticism. In ordinary linear regression models, after adjustment for a number of normal personality characteristics, Schizotypal Personality Traits were still strongly associated with perseverative responses on the Wisconsin Card Sorting Test (WCST). In logistic regression models, subjects with Schizotypal, Schizoid, or Paranoid Traits differed in terms of normal personality profiles and WCST performance.     

Influences of parental rearing on the personality traits of healthy Japanese

Influences of parental rearing on the personality traits of healthy subjects were studied in 323 Japanese volunteers. Perceived parental rearing was assessed with the use of the Parental Bonding Instrument, which consists of the factors of care and protection, whereas personality traits were assessed with the use of the Temperament and Character Inventory, which has 7 dimensions. In male subjects, all personality dimensions except for novelty seeking were influenced by parental rearing; in female subjects, only the harm avoidance (HA) and self-directedness (SD) dimensions were affected by parenting. Paternal rearing influenced 3 dimensions in male subjects and 1 dimension in female subjects, whereas maternal rearing influenced 5 dimensions in male subjects and 2 dimensions in female subjects. In male subjects, higher HA was related to higher paternal protection (P < .05), whereas in female subjects, it was related to higher maternal protection (P < .01). In male subjects, lower SD was related to higher paternal protection (P < .05) and lower maternal care (P < .01), whereas in female subjects, it was related to lower paternal care (P < .05) and higher maternal protection (P < .01). These results suggest that parental rearing influences the personality traits of healthy subjects, especially HA and SD, with sex specificity in parents and recipients.     

Cognitive dimensions in first-episode schizophrenia spectrum disorders

BACKGROUND: The severity and pattern of cognitive deficits in epidemiological cohorts of patients with first-episode schizophrenia spectrum disorders still remains unclear. We aimed to characterize the basic cognitive functioning of a representative sample of patients with a first-episode schizophrenia spectrum disorders. METHOD: One hundred thirty-one patients experiencing first-episode psychosis and 28 healthy volunteers were administered a comprehensive neuropsychological evaluation. To reduce the number of cognitive test measures into meaningful cognitive dimensions, before analyzing differences between patient and healthy volunteer samples, exploratory factor analysis was carried out on data collected in patients group. The method of extraction was Principal Components Analysis with oblique rotation. RESULTS: An eight-factor model including verbal learning/memory, verbal comprehensive abilities, speed of processing/executive functioning, motor dexterity, motor speed, sustained attention, and impulsivity emerged. A significant below average performance in all cognitive dimensions, except impulsivity, was found. Patient's performance in speed of processing/executive functioning, motor dexterity and sustained attention dimensions exceeded one standard deviation below healthy comparison subjects. CONCLUSIONS: At early stages of the illness, patients display a marked impairment in several functionally relevant cognitive domains.     

Neuropsychological dysfunctions in siblings discordant for schizophrenia

Although cognitive impairments are well recognized in patients with schizophrenia, it is unclear which impairments are due to a genetic predisposition and which are caused by secondary disease effects or phenotype. The aim of this study is to investigate the possible relationship between genetic vulnerability to schizophrenia and cognitive functioning. Three groups of subjects were compared: 14 patients with schizophrenia, 15 healthy siblings and 32 healthy control subjects. All subjects were tested neuropsychologically. The raw test data were rescaled to standard equivalents (z-scores). Subjects' z scores on tests assessing the same cognitive domain were clustered and analyzed. Differences in cognitive functioning were found in the domains of abstraction, attention, executive functioning, spatial memory, and sensory-motor functioning. The schizophrenic probands were impaired on all these five domains whereas the healthy probands showed impairments on executive functioning and partially on sensory-motor functioning. Furthermore, for spatial memory the significant finding could mainly be attributed to impaired functioning in the patients, but not healthy siblings or control subjects, whereas for executive functioning patients and healthy siblings seemed equally impaired as compared to control subjects. The planning time of the Tower of London (TOL) and the initiation time of the Motor Planning Task (MPT) were used for measures of executive functioning, while the 'time to move of the Motor Planning Task' was used as measures of sensory motor functioning. These results suggest that the cognitive abnormalities in schizophrenia that may be related to genotype are represented in the domain of executive functioning and to some extent in the domain of sensory-motor functioning.     

Cognitive functioning related to quality of life in schizophrenia

The present study compared the cognitive function of patients with schizophrenia to that of healthy subjects, and investigated the relationships between cognitive function and quality of life (QOL). Participants consisted of 53 patients meeting DSM-IV criteria for schizophrenia and 31 normal controls. All participants completed a neuropsychological test battery assessing executive function, verbal memory, and social knowledge. QOL was rated using the Schizophrenia Quality of Life Scale. Patients with schizophrenia showed lower performance across various cognitive measures of memory, including the Sentence Memory Test, the Verbal Learning Test, and the Script Test, as well as the Rule Shift Cards Test of executive function. Multiple regression analyses were used to evaluate the neuropsychological measures and clinical symptoms to predict QOL. The QOL total score, the social initiative score or the empathy score were significantly predicted by the Script or/and the Sentence Memory. Neuropsychological functioning was unrelated to most QOL scores in the presence of clinical symptoms, while ability of empathy in the QOL was predicted by performance of the Sentence Memory Test. These results demonstrated patients with schizophrenia have deficits in executive function, memory and learning, and social knowledge, and that social knowledge and memory are related to QOL. Thus, in patients with schizophrenia, deficits in social knowledge appear to be associated with current QOL in general, and specifically with the capacity for empathy and social initiative.     

Subcortical brain volumes relate to neurocognition in schizophrenia and bipolar disorder and healthy controls

Background

Similar patterns of subcortical brain abnormalities and neurocognitive dysfunction have been demonstrated in schizophrenia and bipolar disorder, with more extensive findings in schizophrenia. It is unknown whether relationships between subcortical volumes and neurocognitive performance are similar or different between schizophrenia and bipolar disorder.

Methods

MRI scans and neuropsychological test performance were obtained from 117 schizophrenia or 121 bipolar spectrum disorder patients and 192 healthy control subjects. Using the FreeSurfer software, volumes of 18 selected subcortical structures were automatically segmented and analyzed for relationships with results from 7 neurocognitive tests.

Results

In schizophrenia, larger left ventricular volumes were related to poorer motor speed, and bilateral putamen volumes were related to poorer verbal learning, executive functioning and working memory performance. In bipolar disorder, larger left ventricular volumes were related to poorer motor speed and executive functioning. The relationship between left putamen volume and working memory was specific to schizophrenia. The relationships between left inferior lateral ventricles and motor speed and between right putamen volumes and executive functioning were similar in schizophrenia and bipolar disorder, and different from healthy controls. The results remained significant after corrections for use of antipsychotic medication. Significant structure-function relationships were also found when all subjects were combined into one group.

Conclusion

The present findings suggest that there are differences as well as similarities in subcortical structure/function relationships between patients with schizophrenia or bipolar disorder and healthy individuals. The observed differences further suggest that ventricular and putamen volume sizes may reflect severity of cognitive dysfunction in these disorders.