Neuropsychological differences among subtypes of schizophrenia.

Administered the WAIS, the Halstead-Reitan Neuropsychological Test Battery, associated test procedures, and complete neurological evaluations to 140 schizophrenic inpatients. These Ss were subdivided according to 3 criteria: paranoid vs nonparanoid, neurologically normal vs abnormal, and long-term vs short-term institutionalization. Comparisons between groups were made using 3 stepwise discriminant analyses. Although all of these analyses yielded percentages of correct classification that exceeded chance, the greatest accuracy by far was obtained for the long-term vs short-term institutionalization subdivision. Individual tests contributing the most discriminatory power varied from comparison to comparison, with a complex problem-solving test being the best discriminator in the long-term vs short-term comparison and a simple motor test the best discriminator in the other comparisons. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental pathways to schizophrenia: behavioral subtypes

This study examined childhood behavior problems in schizophrenic patients and their healthy siblings. Childhood Behavior Checklist (T. Achenbach, 1991) ratings were obtained from retrospective maternal reports, for 4 age periods: birth to 4 years, 4 to 8 years, 8 to 12 years, and 12 to 16 years. The results indicated that the patients had a variety of childhood behavior problems when compared to their siblings and that the various types of problems differed in their developmental course. Cluster analysis was conducted on the childhood behavior ratings for the schizophrenic patients, and 2 subgroups emerged. Cluster I showed more pronounced behavioral problems than Cluster II, and some of these problems were apparent in early childhood and increased with age. Cluster I also demonstrated greater neuromotor abnormalities in childhood.     

Investigating multiple subtypes of career indecision through cluster analysis.

The primary purpose of this study was to examine and to describe possible subtypes of undecideds through cluster analysis. Eighty-seven undecided and 26 decided students were individually interviewed and completed four instruments on career planning and problem solving. Compared with previous research, this study used more stringent criteria in selecting the undecided students. Also in contrast with previous research, an initial analysis indicated that the decided and undecided students differed on a broad range of career-planning variables. The cluster analysis revealed four distinct subtypes of undecided students, (a) planless avoiders, (b) informed indecisives, (c) confident but uninformed, and (d) uninformed. We discuss the results in terms of previous research, implications for intervention strategies, and methodological issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Another view of schizophrenia subtypes. A report from the international pilot study of schizophrenia

We studied respiratory mechanics in young volunteers before and after 5-wk training programs limited to the ventilatory muscles. Four strength trainers (S) performed repeated static maximum inspiratory and expiratory maneuvers against obstructed airways. Four endurance trainers (E) performed voluntary normocarbic hyperpnea to exhaustion. Subjects spent 30-45 min each day in these exercises, 5 days a week. Four control subjects (C) did no training. We attempted to minimize the effect of learning. S increased pressure maximums by about 55%, but vital capacity and total lung capacity by only about 4%. Initially all subjects could sustain hyperpnea at about 81% of their control 15-s maximum voluntary ventilation (MVV) for 15 min; E increased this to about 96% and increased their MVV by 14% as well. No other statistically significant changes were recognized in any group. We conclude that ventilatory muscle strength or endurance can be specifically increased by appropriate ventilatory muscle training programs.     

Sex differences in schizophrenia: Timing or subtypes?

Reviews evidence for sex differences in the epidemiology, symptom expression, and premorbid social competence of schizophrenia. The data present a general picture of poor premorbid competence, early onset, typical schizophrenia in males, and good premorbid competence, late onset, atypical schizophrenia in females. Two main competing models emerge to account for these sex differences: a timing model and a subtype model. Other interpretations, including misdiagnosis of affective disorders as schizophrenia and the overlay of general sex-role styles on psychopathology, are also examined. (2? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological differences among empirically derived clinical subtypes of schizophrenia.

Neuropsychological profile differences between empirically derived clinical subtypes of schizophrenia were examined. Two hundred five patients and 209 demographically matched controls were administered a neuropsychological battery examining 8 domains. Subtypes included negative, disorganized, paranoid, Schneiderian, and mild. All subtypes displayed a neuropsychological profile of generalized impairment with greater deficits in learning, memory, and attention. Results were suggestive of diffuse cognitive dysfunction in schizophrenia with more severe deficits in learning and memory relative to executive skills. This pattern of greater learning and memory impairment was pronounced for disorganized patients. In contrast, paranoid patients outperformed disorganized and negative patients in several domains. These findings reflect bilateral frontal–temporal dysfunction, particularly in disorganized and negative patients. Subtype differences highlight the importance of conceptualizing schizophrenia as a multifocal disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of nearest-neighbor and cluster analyses in pharmaceutical lead discovery

CASE REPORT: A case history of unanticipated radiation-induced bilateral optic neuropathy, 18 months after induction chemotherapy and radiation therapy for a locally advanced nasopharyngeal carcinoma, is presented. Retrospective reanalysis of the radiation therapy technique, with emphasis on the doses received by the optic pathway structures, was performed. These re-calculations revealed unexpectedly high doses in the range 79 to 82 Gy (cumulative external and brachytherapy dose) at the level of the optic nerves, which explained the observed radiation injury. CONCLUSION: Routine implementation of computed tomography for 3D dose planning purposes is therefore advocated. Review of the current literature confirms the importance of 3D dose planning in avoiding this complication and high-lights the role of MRI in establishing the diagnosis of radiation-induced optic neuropathy.     

Empirically derived subtypes of pervasive developmental disorders: a cluster analytic study

A cluster analytic study was conducted to empirically derive behaviorally homogeneous subtypes of pervasive developmental disorders (PDD). Subjects were clustered based on a broad range of behavioral symptoms which characterize autism. Behavioral variables were measured using several of the standardized psychometric instruments most commonly employed in assessing autistic individuals. The cluster solution indicated the presence of four distinct groups. Validity checks generally confirmed significant between-group differences on independent measures of social, language, and stereotyped behaviors. In addition, the four-group cluster solution was compared to previously developed typological systems of PDD (i.e., subcategories based on IQ early onset, styles of social interaction, and DSM-III-R diagnosis). Results generally supported both the behavioral homogeneity of the four subgroups and also several important between-group differences. The potential utility of using cluster analyses to explore subtypes of PDD is discussed.     

Gross brain morphology in schizophrenia: A regional analysis of traditional diagnostic subtypes.

56 patients with chronic schizophrenia were categorized into 2 groups based on traditional diagnostic subtypology. They were then compared on indices of cortical and subcortical CSF volume to explore whether the more virulent nonparanoid disorder was linked to cortical or subcortical morphological brain abnormalities. They were examined also to determine whether abnormalities in a specific cerebral region were related to greater chronicity or severity of schizophrenia. The 2 groups differed significantly only in subcortical but not cortical CSF volume. The regional changes, however, did not appear to characterize exclusively the virulent subtypes. The results and their implications for future studies on the neuroanatomical correlates of schizophrenia subtypes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identifying psychophysiological risk for psychopathology: examples from substance abuse and schizophrenia research

A problem confronting the search for psychopathology-related genes concerns the difficulty identifying gene carriers. Psychiatric diagnosis provides imperfect identification of affected individuals, and unaffected gene carriers go undetected. Psychophysiological measures may assist molecular genetic investigations by indicating genetic susceptibility for psychopathology, thus increasing the probability of identifying affected and unaffected gene carriers. Research strategies based on these premises are applied to the study of psychoactive substance use disorders and schizophrenia. Data are presented illustrating (1) that individual differences in inhibitory control involving autonomic and antisaccade eye movement measures and the P3 component of the event-related potential may be sensitive to susceptibility for substance use disorders, and (2) that eye tracking variables may identify genetic risk for schizophrenia.     

A neuropsychological study of prefrontal lobe function in the positive and negative subtypes of schizophrenia

The symptoms of schizophrenia are frequently divided into positive and negative subtypes. It has been suggested that the negative symptoms are similar to those seen with prefrontal lobe cortical dysfunction. Several neuropsychological investigations of that hypothesis have been carried out, but none have directly compared a negative symptom group with a positive symptom group on the same test battery. In the present study, the Positive and Negative Syndrome Scale (PANSS; Kay, Fiszbein, & Opler, 1987) was used to distinguish two groups of 20 patients with schizophrenia with predominant positive or negative symptoms. A battery of 7 neuropsychological tests considered capable of isolating prefrontal lobe dysfunction was administered. A significant group difference was noted on 6 of the tests; the negative symptom group performed much worse than the positive symptom group. The results of this study support the hypothesis that a relationship exists between the negative symptoms of schizophrenia and prefrontal lobe dysfunction.     

Memory-delineated subtypes of schizophrenia: Relationship to clinical, neuroanatomical, and neurophysiological measures.

Memory performance was examined in patients with schizophrenia to determine whether subgroups conforming to cortical and subcortical dementias could be identified and, if so, whether subgroups differed on clinical, neuroanatomical, and neurophysiological measures. A cluster analysis of California Verbal Learning Test performance classified patients into 3 subgroups. Two groups exhibited memory deficits consistent with the cortical-subcortical distinction, whereas 1 group was unimpaired. Cortical patients tended to be male, and they had earlier illness onset, reduced temporal lobe gray matter, and hypometabolism. Subcortical patients had ventricular enlargement and more negative symptoms. Unimpaired patients had fewer negative symptoms and dorsal medial prefrontal hypermetabolism. The authors conclude that categorizing patients on the basis of memory deficits may yield neurobiologically meaningful disease subtypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Symptom subtypes in persons institutionalized with schizophrenia: Comparison of demographics, outcome and functional skills.

Using a formula based on the concept by N. C. Andreasen (see record 1982-29376-001) and N. C. Andreasen and S. Olsen (see record 1982-30452-001) of classifying subtypes into positive, negative, and mixed schizophrenia, 312 persons institutionalized with Diagnostic and Statistical Manual of Mental Disorders (DSM-III) schizophrenia were retrospectively examined. 59 Ss were classified into the positive symptom subtype, 33 into the negative symptom subtype, and 220 into the mixed symptom subtype. Symptom subtypes were compared on traditional demographic and outcome indicators, as well as on a dimension critical to rehabilitation (i.e., measures of degree of assistance necessary to perform functional skills). No significant differences were found among the subtypes on demographic items and traditional indicators of outcome such as level of vocational functioning or independent living. However, on measures of degree of assistance necessary to perform functional skills, significant differences were found among the symptom subtypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bifactor and item response theory analyses of interviewer report scales of cognitive impairment in schizophrenia.

A psychometric analysis of 2 interview-based measures of cognitive deficits was conducted: the 21-item Clinical Global Impression of Cognition in Schizophrenia (CGI-CogS; Ventura et al., 2008), and the 20-item Schizophrenia Cognition Rating Scale (SCoRS; Keefe et al., 2006), which were administered on 2 occasions to a sample of people with schizophrenia. Traditional psychometrics, bifactor analysis, and item response theory methods were used to explore item functioning and dimensionality and to compare instruments. Despite containing similar item content, responses to the CGI-CogS demonstrated superior psychometric properties (e.g., higher item intercorrelations, better spread of ratings across response categories) relative to the SCoRS. The authors argue that these differences arise mainly from the differential use of prompts and how the items are phrased and scored. Bifactor analysis demonstrated that although both measures capture a broad range of cognitive functioning (e.g., working memory, social cognition), the common variance on each is overwhelmingly explained by a single general factor. Item response theory analyses of the combined pool of 41 items showed that measurement precision is peaked in the mild to moderate range of cognitive impairment. Finally, simulated adaptive testing revealed that only about 10 to 12 items are necessary to achieve latent trait level estimates with reasonably small standard errors for most individuals. This suggests that these interview-based measures of cognitive deficits could be shortened without loss of measurement precision. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Muscarinic cholinergic receptor subtypes expression by human placenta

The presence of a cholinergic system in the placenta is suggested by several data, but no information is available concerning cholinergic receptor expression by placenta. The present study was designed to investigate muscarinic cholinergic receptors in sections of human placenta using a radioligand binding techniques with [3H]N-methyl scopolamine ([3H]NMS) as a ligand. [3H]NMS was bound to sections of human placenta in a manner consistent with the labelling of muscarinic cholinergic receptors. The dissociation constant (Kd) value was 0.1 +/- 0.03 nM and the maximum density of binding site (Bmax) value was 10.82 +/- 0.09 fmol/mg of tissue. The binding was time-, temperature- and concentration-dependent, belonging to one class of high affinity sites. Analysis of [3H]NMS displacement curves by compounds acting on the different subtypes of muscarinic cholinergic receptor subtypes suggests that human placenta expresses the four subtypes (M1-M4) of muscarinic cholinergic receptor assayable with radioligand binding assay techniques. The demonstration of muscarinic cholinergic recognition sites in human placenta may contribute to define the possible significance of placental cholinergic system. Moreover, human placenta can be used as an easily obtainable human source of M1-M4 muscarinic cholinergic receptor subtypes.     

In vitro electro-pharmacological and autoradiographic analyses of muscarinic receptor subtypes in rat hypothalamic ventromedial nucleus: implications for cholinergic regulation of lordosis

Muscarinic agonists can act through the hypothalamic ventromedial nucleus (VMN) to facilitate lordosis. To elucidate the neuronal mechanism(s) underlying this muscarinic facilitation, effects of muscarinic agents on the single-unit activity of VMN neurons recorded in brain tissue slices of estrogen-primed female rats were analyzed. All the agonists tested, including acetylcholine (ACh), oxotremorine-M (OM), carbachol (CCh) and McN-A-343 (McN), evoked primarily excitation (80-100%), some inhibition (0-20%) and occasional biphasic responses (0-8%). By comparing the response magnitude and the effectiveness in evoking a response, the rank order for evoking excitation, the primary response, was found to be: OM > CCh > ACh approximately McN, which is consistent with that (OM > CCh > McN) for facilitating lordosis reported by others. This consistency and the frequency of its occurrence suggest that the excitatory electric action of the muscarinic agonists is related to their facilitatory behavioral effect. Experiments with antagonists selective for M1 (pirenzepine), M2 (AF-DX 116) and M3 (4-DAMP and p-F-HHSiD) indicate that muscarinic excitations are mediated by M1 and/or M3, but not M2. Since M1 receptors have been shown to be neither sufficient nor necessary to mediate the muscarinic facilitation, M3 receptor may be crucially involved in this behavioral effect. Autoradiographic assays of binding to [3H]4-DAMP with or without pirenzepine and AF-DX 116, also indicate the presence of M3 receptors in the VMN. Quantitative analyses show that the M3 binding was not affected by the in vivo estrogen priming required to permit muscarinic agonists to facilitate lordosis. Thus, while the excitation mediated by M3 is likely to be involved in muscarinic facilitation of lordosis, the regulation of M3 receptor density does not seem to be involved in the permissive     

Identifying children who are rejected by their peers.

Recent research indicates the importance of distinguishing between sociometrically neglected children and sociometrically rejected children. However, making the distinction between neglected status and rejected status traditionally has required administering a negative-nomination sociometric measure, a measure viewed by some researchers and school personnel as having potentially harmful effects. An alternative method of identifying rejected children is proposed and evaluated that involves the joint use of positive-nomination and rating-scale measures. Rating-scale, positive-nomination, and negative-nomination measures were administered to 747 children in Grades 2–6. The results indicate that the alternative method accurately identified a high percentage of rejected Ss (91.2%) and that the stability of rejected status, identified using the new method, is similar to that obtained in previous research. It is concluded that the method proposed should make it possible to identify rejected children when circumstances do not allow for the administration of a negative-nomination measure. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)