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The Annett Hand Preference Questionnaire (AHPQ) was administered to a sample of 352 randomly selected individuals from the general community to examine the reproducibility of its handedness classification and to evaluate its model-based reliability and convergent validity. Latent class analysis showed that the eight categories of hand preferences could not be justified on statistical grounds. Instead, three broad handedness classes adequately accommodated the variety of handedness patterns: ‘ consistent right’ (66.0%), ‘ consistent left’ (9.8), and ‘ inconsistent or mixed’ (24.2%). Confirmatory factor analysis showed that the AHPQ is reliable and has solid convergent validity, but also showed that measurement properties of the AHPQ could be further improved by eliminating a few items from the scale. The implications of these findings are discussed, and it is suggested that questionnaire requires modification, possibly by replacing obsolete items such as ‘ sweeping’ and ‘ shovelling’ with modern manual activities such as ‘ typing SMS messages’ and ‘ using a remote control’ .

The goal of the present study was to examine the influence of age and gender on the factor structure of the Schizotypal Personality Questionnaire (Raine, 1991). Schizotypal traits were assessed in a random sample of mature, adult community volunteers (average age 40 years). Four competing models of the latent factor structure were tested in the full sample (N = 352). The resulting three-factor model was then assessed separately in males and females and in stratified subsamples, reflecting three age cohorts. The results showed that, in mature adults, males had higher scores than females on No Close Friends and Constricted Affect whilst females had higher scores on Social Anxiety and Odd Beliefs subscales. Older adults were also characterized by lower total SPQ scores than those reported previously for younger adults. Despite the presence of age and sex-related differences in mean SPQ scores, a three-factor model of schizotypal personality best characterized the SPQ responses from mature adults, replicating that reported previously in high-school and university-aged samples. The implications of these findings of SPQ factor structure invariance, across age and gender, are discussed with reference to studies investigating neurocognitive correlates of schizotypy (ie. endophenotypes).

Aims/Background Hallmayer et al. (2005) recently identified a homogeneous subtype of schizophrenia characterized by pervasive cognitive deficit (CD), which appears to have a distinct genetic basis. The aim of this report is to present a single case approach to further characterize the cognitive performance of individuals identified as belonging to the CD subtype. Methods Individual performance variability was examined across a battery of cognitive tests in terms of: 1) the percentage of individuals classified with abnormally low scores, 2) the number of individuals with multiple, single or no cognitive deficits and 3) scatterplots of individual scores on immediate memory. Results All CD patients, except one, were impaired in their immediate recall of words, gaining an average of only 2.8 words across trials, compared with 4.9 words in healthy controls with lower verbal memory ability. Over 90% showed impaired current intelligence ; all CD patients had at least 3 cognitive deficits and approximately one third had deficits on all seven cognitive tests. In contrast only 76% were classified with abnormal performance on verbal fluency. Conclusions In the CD subtype verbal memory impairment is the most consistently observed cognitive deficit. Multiple (3+) cognitive deficits were exhibited by all CD cases and estimated current IQ was also low in the majority of these patients. Consequently, generalized cognitive deficiency appears to be a valid term to describe the cognitive characteristics of this subtype. However, executive dysfunction may not be essential to the CD subtype since approximately one quarter of patients were unimpaired in this domain.

Background Two homogeneous schizophrenia subtypes, each featuring a specific configuration of neurocognitive performance, neurobehavioral anomalies and selected personality measures, were identified in our previous study (Hallmayer et al., 2005). The first, “ Cognitive Deficit” (CD) type, comprising patients and a small number of unaffected relatives (n = 76), displayed pervasive deficit on almost all neurocognitive measures. Family members assigned to the remaining types (n = 312) were close to controls on neurocognitive measures but showed significantly deviant scores on temperament and character scales and three dimensions of schizotypy, and were pooled into Non-CD type. Methods Using canonical correlation analysis we examined whether specific profiles of personality, assessed by the Temperament and Character Inventory (Cloninger et al., 1993) were related to schizotypal dimensions, assessed by the Schizotypal Personality Questionnaire (Raine 1991). Once the relationship was confirmed, we examined its invariance across both groups. Results Simple mean scores on personality scales and schizotypy factors were generally uninformative, with siblings of schizophrenia patients having virtually identical scores on almost all scales as their parents. However, distinct associations between structure of personality traits (temperament and character) and schizotypal factors emerged in the two schizophrenia subtypes. Conclusion A simple clinical, primarily negative, symptomatology in CD patients is probably due to reduced cognitive efficiency, whereas dysfunctional cognitive control could be responsible for more prominent positive symptoms in Non-CD patients and their clinically unaffected first degree relatives. This is consistent with Kraepelin’ s observations that prominent signs of schizophrenia include a lessened ability to produce ideas and concepts and diminished capacity to sift, arrange and correct the existing ones.

Background: Various behavioural indices of brain lateralisation significantly intercorrelate, but current research in this area still focuses on single behavioural asymmetries, such as handedness. Aim: To describe a novel approach, which simultaneously integrates various laterality indices and delineates complex phenotypes. Method Grade of membership (GoM) analysis was used to describe latent, complex lateralisation phenotypes in schizophrenia patients, their siblings and controls. The indices used were: (i) asymmetries of eye, foot and hand ; (ii) hand motor proficiency ; and (iii) handedness of patient’ s first-degree relatives. Results: Three distinct pure types of lateralisation (‘ right’ , ‘ left’ and ‘ mixed’ ) were evident in patients compared to two (‘ right’ and ‘ left’ ) in siblings and controls. The ‘ mixed’ type in patients featured absence of eye and foot lateralisation, and presence of familial sinistrality, despite a right-hand dominance for writing. Patients with schizophrenia expressing the ‘ left’ phenotype had a more severe course of illness, significantly increased scores on two schizotypy factors and poorer neurocognitive performance. The pure types in the siblings were similar to those in healthy controls. Conclusions: The findings suggest that a leftward reversal, rather than a reduction in lateralisation, is associated with clinical severity and neurocognitive deficits in patients with schizophrenia.

There is a growing literature describing a subgroup of “ high-functioning” people with schizophrenia who show preserved intellectual ability (IQ). A detailed characterisation of the cognitive abilities of this group may be important in targeting appropriate treatment, management and services for patients with schizophrenia. It is a widely held belief that variation in cognitive processing speed is the basis of individual differences in intelligence. The main objective of this study was to identify subgroups of schizophrenia patients with preserved (N = 45), deteriorated (N= 47) and compromised (N = 17) intellect in order to study whether these subgroups differ in specific cognitive abilities (eg. executive functions) or in general cognitive processing speed, as measured with an inspection time (IT) task. The patients who displayed an average estimated premorbid IQ, with no evidence of IQ decline (premorbid-current IQ difference < 10 points), were found to show better performance on measures of executive function (Continuous Performance Task, Verbal Fluency) compared with patients in the deteriorated and compromised subgroups. Nevertheless, this represented significantly impaired performance relative to healthy controls. In contrast, the average inspection times of patients with preserved IQ were as slow as those obtained in the deteriorated or compromised groups, indicating that high functioning patients are impaired in terms of cognitive processing speed. Furthermore, the average IT for all schizophrenia groups was significantly slower than that of healthy controls. These findings suggest that high functioning patients with schizophrenia exhibit enduring cognitive difficulties that may impact on their ability to benefit from rehabilitation interventions.

Two homogeneous schizophrenia subtypes, each featuring a specific configuration of neurocognitive performance, neurobehavioural anomalies and selected personality measures, were identified in our previous study. The first, “ Cognitive Deficit” (CD) type, comprising patients and a small number of unaffected relatives (n = 76), displayed pervasive deficit on almost all neurocognitive measures. Family members assigned to the remaining types (n = 312) were close to controls on neurocognitive measures but showed significantly deviant scores on temperament and character scales and three dimensions of schizotypy, and were pooled into Non-CD type. We examined whether specific profiles of personality were related to schizotypal dimensions and, once the relationship was confirmed, whether such a link was invariant across both groups. Additionally, this link was also investigated in a sample of healthy community controls (n = 143). Simple mean scores on personality scales and schizotypy factors were generally uninformative, with relatives of schizophrenia patients having virtually identical scores on almost all scales as control subjects. However, distinct associations between structure of personality traits (temperament and character) and schizotypal factors emerged in the two schizophrenia subtypes. Whereas reduced cognitive efficiency in CD patients was primarily reflected in negative symptomatology, dysfunctional cognitive control could be responsible for more prominent positive symptoms in Non-CD patients, their clinically unaffected relatives, and controls.

This work evaluates evidence of various anomalous handedness subtypes in schizophrenia patients published during the last three decades. Using meta-analsys we examined over 40 studies with reported prevalence data on various handedness subtypes in a schizophrenia population. Combined odds ratios for the three common handedness subtypes (left, mixed, and right) were separately calculated. Each of the three atypical hand dominance patterns (left-, mixed-, and non-right handedness) were significantly greater in schizophrenia patients than in control subjects. The results also showed that the leftward shift in handedness distribution is not entirely due to an increase in mixed-handedness alone. An increase of exclusive left-handedness is discordant with the assertion that the handedness shift in schizophrenia patients is due to a diffuse and bilateral hemispheric insult.

A novel phenotyping strategy in schizophrenia, targeting different neurocognitive domains, neurobehavioral features, and selected personality traits, has allowed us to identify a homogeneous familial subtype of the disease, characterized by pervasive neurocognitive deficit. Our genome scan data indicate that this subtype, which accounts for up to 50% of our sample, has a distinct genetic basis and explains linkage to chromosome 6p24 reported previously. If representative of other populations, the ratio of schizophrenia subtypes observed in our families could have a profound impact on sample heterogeneity and on the power of genetic studies to detect linkage and association. Our proposed abbreviated battery of tests should facilitate phenotype characterization for future genetic analyses and allow a focus on a crisply defined schizophrenia subtype, thus promoting a more informed search for susceptibility genes.

A view that handedness is not a dichotomous i.e. left-right phenomenon is shared by majority of researchers. However, there are different opinions about the exact number of hand preference categories and criteria that should be used for their classification. This study examined hand preference categories using the Latent Class Analysis (LCA) and validated them against two external criteria (i.e. hand demonstration test and a series of arbitrary cut-off points). The Edinburgh Handedness Inventory was applied to 354 individuals randomly selected from the general population and the obtained data were analysed using the LatentGOLD software. Three discrete hand preference clusters were identified i.e. left-, right- and mixed-handed category. Further subdivision of hand preference clusters resulted in a non-parsimonious subcategorization of individuals. There was a good agreement between the LCA -based classification and classification based on hand preference demonstrations tests. The highest agreement between the LCA model and different types of arbitrary classification criteria ranged between 0 50 and 0 70 of the laterality quotient. The study findings supported the view that handedness is not a bimodal phenomenon. However, definitions and subcategorisations of mixed-handedness using the cut-off points that are outside of recommended range may lead to misclassification of cases. It is hoped that the categorisation and validation of handedness developed in the context of this study will make future research in this area less dependent on arbitrary values and criteria.

Bz means of meta-analsys we examined over 40 studies published over the last few decades with reported prevalence data on various handedness subtypes in a schizophrenia population. Each of the three atypical hand dominance patterns (left-, mixed-, and non-right handedness) were significantly greater in schizophrenia patients than in control subjects. The results also showed that the leftward shift in handedness distribution is not entirely due to an increase in mixed-handedness alone.

As schizophrenia is genetically and clinically heterogeneous, systematic investigations are required to determine whether ICD-10 or DSM-IV categorical diagnoses identify a phenotype suitable and sufficient for genetic research, or whether correlated phenotypes incorporating neurocognitive performance and personality traits provide a phenotypic characterisation that accounts better for the underlying variation. We utilised a grade of membership (GoM) model (a mathematical typology developed for studies of complex biological systems) to integrate multiple cognitive and personality measurements into a limited number of composite graded traits (latent pure types) in a sample of 61 nuclear families comprising 80 subjects with ICD-10/ DSM-IV schizophrenia or schizophrenia spectrum disorders and 138 nonpsychotic first degree relatives. GoM probability scores, computed for all subjects, allowed individuals to be partly assigned to more than one pure type. Two distinct and contrasting neurocognitive phenotypes, one familial, associated with paranoid schizophrenia, and one sporadic, associated with nonparanoid schizophrenia, accounted for 74% of the affected subjects. Combining clinical diagnosis with GoM scores to stratify the entire sample into liability classes, and using variance component analysis (SOLAR), in addition to parametric and nonparametric multipoint linkage analysis, we explored candidate regions on chromosomes 6, 10 and 22. The results indicated suggestive linkage for the familial neurocognitive phenotype (multipoint MLS 2.6 under a low-penetrance model and MLS43.0 under a high-penetrance model) to a 14 cM area on chromosome 6, including the entire HLA region. Results for chromosomes 10 and 22 were negative. The findings suggest that the familial neurocognitive phenotype may be a pleiotropic expression of genes underlying the susceptibility to paranoid schizophrenia. We conclude that use of composite neurocognitive and personality trait measurements as correlated phenotypes supplementing clinical diagnosis can help stratify the liability to schizophrenia across all members of families prior to linkage, allow the search for susceptibility genes to focus selectively on subsets of families at high genetic risk, and augment considerably the power of genetic analysis.

Although behavioural indices of brain lateralisation are intercorrelated, current research in this area still focuses on isolated behavioural asymmetries, such as shift in handedness. Simultaneous integration of various laterality indices to delineate complex phenotypes might be a more productive research approach. In this study we used a version of latent class analysis - the Grade of Membership model - to describe complex lateralisation phenotypes in schizophrenic patients, their unaffected siblings and controls. The selected indices were: eye, foot and hand asymmetries ; motor proficiency ; and putative genetic indicants (parent’ s handedness, sibling’ s handedness, and familial sinistrality). Three “ pure type” lateralisation patterns were derived from schizophrenia patients and their unaffected siblings, as compared to healthy controls, where only two patterns were found. In the group of schizophrenia patients, lateralisation phenotypes (two leftward and one rightward) showed distinct clinical and behavioural profiles. One of the leftward phenotypes in schizophrenia patients displayed greater clinical severity (lower age at onset, frequent hospital admissions, and more antipsychotic medication) and poorer neurocognitive performance (lower current IQ, poorer sustained attention, and slower speed of information processing). The characterisation of pure lateralisation types in unaffected siblings revealed closer phenotypic similarity to schizophrenia patients, than to controls, thus suggesting a possible genetic effect.

Based on a critical literature review, this study re-examines the claim that mixed-handedness might be a presumed neurodevelopmental marker of both schizophrenia and schizotypy. Handedness was assessed with a standardized handedness questionnaire and schizotypy with the SPQ in a large community sample, in a “ highly healthy” sample, in siblings of schizophrenia, and in patients with schizophrenia. The results did not show a specific relationship between mixed-handedness and features of schizotypy. Only the cognitive-disorganization factor of the SPQ was related to a higher incidence of mixed-handedness, significantly in patients with schizophrenia and as a statistical trend in siblings of patients with schizophrenia. These findings add to the inconsistent observations on reduced laterality along the schizophrenia spectrum, supporting previous notions “ Re-examining handedness in schizophrenia: now you see it-now you don't” (Nelson et al., 1993).

Ovaj rad daje sažet pregled novije literature o atipičnoj manuelnoj lateralizaciji kod pacijenta sa šizofrenim poremećajem. Napisan je sa svrhom da ovaj fenomen približi psiholozima, kao i ostalim zainteresovanim kolegama iz drugih naučnih disciplina. U pregledu literature je uvršten kratak opis teorije pomaka u desno (The Right Shift Theory), koja predstavlja najuticajniji teorijski koncept u ovoj oblasti, kao i diskusija o nekoliko drugih važnih tema kao što su – evolucioni aspekt lateralizacije ruku, problem ispitivanja, kao i teorije nasleđivanja. Veći deo teksta ima za cilj da izloži savremena kretanja i moguće pravce budućih istraživanja atipične upotrebe ruku kod šizofrenih pacijenata. Tokom poslednjih nekoliko decenija većina objavljenih radova podržava nedoslednost u upotrebui ruku, ne levorukost, kao specifičnu za šizofreniju. Takođe, postoji značajna asocijacija između specifičnih kognitivnih deficita, kliničke psihopatologije i nedoslednosti u preferiranoj upotrebi ruku. Većina studija podržava stav da je redukcija cerebralne lateralizacije ključna antomska karakteristika kod pacijenata sa šizofrenim poremećajem. Daljnji istraživački rad na razumijevanju ovog fenomena je neophodan.

We demonstrate a novel method for constructing composite quantitative phenotypes for QTL analysis in schizophrenia. In 124 patients, 202 first-degree relatives, and 71 controls, a neurocognitive battery identified deficits (2 SD below the mean of the controls) in attention, verbal fluency, IQ and speed of processing in 62% of patients, 36 % of relatives and 7% of controls (p

This paper investigates prevalence of atypical lateralisation of hand preferences in schizophrenia patients and their asymptomatic first-degree relatives. The presence of mixed- (OR=3.766 ; 95%CI=1.93-7.35 ; p

Several ocular motor abnormalities have been observed in schizophrenia. Amongst these is impaired performance on the antisaccade condition of step saccade tasks. In the antisaccade condition participants are required to inhibit a reflexive saccade to a target in the periphery of one visual field, and generate a voluntary saccade to a mirror image position in the opposite visual field. This task condition is thought to primarily tap inhibitory, and to a lesser degree working memory, capacities located in the prefrontal cortex. Existing evidence shows that schizophrenics and their unaffected first-degree biological relatives have unimpaired prosaccade performance, but significantly impaired ability to inhibit reflexive saccades in the antisaccade condition. The present study examined the prosaccade and antisaccade performance of 40 clinically diagnosed schizophrenic patients, 50 unaffected first-degree biological relatives, and 30 controls free of psychiatric diagnosis. Initial analysis is consistent with existing evidence that individuals with schizophrenia show significantly poorer antisaccade performance than controls, and the antisaccade performance of first-degree biological relatives’ falls between these two groups. There was no significant difference between the groups in prosaccade performance or rates of self-correction of incorrect saccades. The presentation will report on these data and their relationship to other neurocognitive measures, in particular, sustained attention and speed of processing.

Sistematsko ispitivanje profesionalnih opredeljenja učenika osnovnih i srednjih škola je kontinuirana delatnost Republičkog Zavoda za tržište rada Srbije. Pored ispitivanja profesionalnih planova, prikupljaju se i ostali relevatni podaci o profesionalnom razvoju učenika kao što su spremnost za promenu zanimanja, dugoročni planovi u profesionalnom razvoju. Kontinuiranost ove delatnosti, primena istog instrumentarija i metodologije, obuhvat iste populacije, elementi su koji ovo ispitivanje pretvaraju u tzv. pseudolongitudinalnu studiju praćenja profesionalnih opredeljenja učenika. Uzorak na kojem je provedeno ispitivanje u 1996-1997 školskoj godini iznosi 7394 učenika.