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Over the last three decades, movement disorder as well as sensorimotor and psychomotor functioning in schizophrenia (SZ) and other psychoses has gained greater scientific and clinical relevance as an intrinsic component of the disease process of psychotic illness; this extends to early psychosis prediction, early detection of motor side effects of antipsychotic medication, clinical outcome monitoring, treatment of psychomotor syndromes (e.g. catatonia), and identification of new targets for non-invasive brain stimulation. In 2017, a systematic cooperation between working groups interested in movement disorder and sensorimotor/psychomotor functioning in psychoses was initiated across European universities. As a first step, the members of this group would like to introduce and define the theoretical aspects of the sensorimotor domain in SZ and other psychoses. This consensus paper is based on a synthesis of scientific evidence, good clinical practice and expert opinions that were discussed during recent conferences hosted by national and international psychiatric associations. While reviewing and discussing the recent theoretical and experimental work on neural mechanisms and clinical implications of sensorimotor behavior, we here seek to define the key principles and elements of research on movement disorder and sensorimotor/psychomotor functioning in psychotic illness. Finally, the members of this European group anticipate that this consensus paper will stimulate further multimodal and prospective studies on hypo- and hyperkinetic movement disorders and sensorimotor/psychomotor functioning in SZ and other psychotic disorders. (C) 2020 Elsevier B.V. and ECNP. All rights reserved.

(1) Background: Our aims in this study were (i) to compare effort allocation capacity measured between patients with recent-onset schizophrenia (SCZ) and healthy controls (HCs), (ii) within the SCZ, to investigate the association of effort allocation capacity with negative symptoms (NS), and (iii) to compare this association with the type of NS scale used. (2) Methods: Thirty-one patients with SCZ and 30 HCs participated in the study. The NS was examined using an older-generation (Scale for the Assessment of Negative Symptoms, SANS), a newer-generation (Brief Negative Symptoms Scale, BNSS), and a self-rated (Self-evaluation of Negative Symptoms Scale, SNS) negative symptom scale, as well as longitudinally by using persistent NS (PNS) distinction. (3) Results: The SCZ group was less willing to expend effort in high/moderate-probability and -magnitude conditions but more in low-probability and -magnitude conditions. A general reduction in effort allocation capacity was also present. Patients with PNS were less likely to choose hard tasks than non-PNS patients. Clinician-rated scales correlated with 50% probability and moderate-reward-magnitude conditions. Correlations with the SNS were minimal. (4) Conclusions: Our findings suggest that patients with SCZ may show a general reduction in effort allocation capacity and make inefficient choices, although they are not totally reward-insensitive. The effects of NS on effort expenditure can be more pronounced when the rewarding stimulus is vague.

Over the last three decades, movement disorder as well as sensorimotor and psychomotor functioning in schizophrenia (SZ) and other psychoses has gained greater scientific and clinical relevance as an intrinsic component of the disease process of psychotic illness; this extends to early psychosis prediction, early detection of motor side effects of antipsychotic medication, clinical outcome monitoring, treatment of psychomotor syndromes (e.g. catatonia), and identification of new targets for non-invasive brain stimulation. In 2017, a systematic cooperation between working groups interested in movement disorder and sensorimotor/psychomotor functioning in psychoses was initiated across European universities. As a first step, the members of this group would like to introduce and define the theoretical aspects of the sensorimotor domain in SZ and other psychoses. This consensus paper is based on a synthesis of scientific evidence, good clinical practice and expert opinions that were discussed during recent conferences hosted by national and international psychiatric associations. While reviewing and discussing the recent theoretical and experimental work on neural mechanisms and clinical implications of sensorimotor behavior, we here seek to define the key principles and elements of research on movement disorder and sensorimotor/psychomotor functioning in psychotic illness. Finally, the members of this European group anticipate that this consensus paper will stimulate further multimodal and prospective studies on hypo- and hyperkinetic movement disorders and sensorimotor/psychomotor functioning in SZ and other psychotic disorders. (C) 2020 Elsevier B.V. and ECNP. All rights reserved.

IMPORTANCE The value of early intervention in psychosis and allocation of public resources has long been debated because outcomes in people with schizophrenia spectrum disorders have remained suboptimal. OBJECTIVE To compare early intervention services (EIS) with treatment as usual (TAU) for early-phase psychosis. DATA SOURCES Systematic literature search of PubMed, PsycINFO, EMBASE, and ClinicalTrials. gov without language restrictions through June 6, 2017. STUDY SELECTION Randomized trials comparing EIS vs TAU in first-episode psychosis or early-phase schizophrenia spectrum disorders. DATA EXTRACTION AND SYNTHESIS This systematic reviewwas conducted according to PRISMA guidelines. Three independent investigators extracted data for a random-effects meta-analysis and prespecified subgroup and meta-regression analyses. MAIN OUTCOMES AND MEASURES The coprimary outcomeswere all-cause treatment discontinuation and at least 1 psychiatric hospitalization during the treatment period. RESULTS Across 10 randomized clinical trials (mean [SD] trial duration, 16.2 [7.4] months; range, 9-24 months) among 2176 patients (mean [SD] age, 27.5 [4.6] years; 1355 [62.3%] male), EIS was associated with better outcomes than TAU at the end of treatment for all 13 meta-analyzable outcomes. These outcomes included the following: all-cause treatment discontinuation (risk ratio [RR], 0.70; 95% CI, 0.61-0.80; P

Importance: The value of early intervention in psychosis and allocation of public resources has long been debated because outcomes in people with schizophrenia spectrum disorders have remained suboptimal. Objective: To compare early intervention services (EIS) with treatment as usual (TAU) for early-phase psychosis. Data Sources : Systematic literature search of PubMed, PsycINFO, EMBASE, and ClinicalTrials.gov without language restrictions through June 6, 2017. Study Selection: Randomized trials comparing EIS vs TAU in first-episode psychosis or early-phase schizophrenia spectrum disorders. Data Extraction and Synthesis: This systematic review was conducted according to PRISMA guidelines. Three independent investigators extracted data for a random-effects meta-analysis and prespecified subgroup and meta-regression analyses. Main Outcomes and Measures: The coprimary outcomes were all-cause treatment discontinuation and at least 1 psychiatric hospitalization during the treatment period. Results Across 10 randomized clinical trials (mean [SD] trial duration, 16.2 [7.4] months; range, 9-24 months) among 2176 patients (mean [SD] age, 27.5 [4.6] years; 1355 [62.3%] male), EIS was associated with better outcomes than TAU at the end of treatment for all 13 meta-analyzable outcomes. These outcomes included the following: all-cause treatment discontinuation (risk ratio [RR], 0.70; 95% CI, 0.61-0.80; P

Upregulation of selenium binding protein 1 (SELENBP1) mRNA expression has been reported in schizophrenia, primarily in the dorsolateral prefrontal cortex. However, peripheral blood studies are limited and results are inconsistent. In this study, we examined SELENBP1 mRNA expression in whole blood and protein expression in plasma from patients with recent-onset schizophrenia (n = 30), treatment-resistant schizophrenia (n = 71) and healthy controls (n = 57). We also examined the effects of SELENBP1 genetic variation on gene and protein expression. We found lower SELENBP1 plasma protein levels in patients with recent-onset schizophrenia (p = 0.042) but not in treatment-resistant schizophrenia (p = 0.81). Measurement of peripheral mRNA levels showed no difference between treatment-resistant schizophrenia and healthy controls (p = 0.234) but clozapine plasma levels (p = 0.036) and duration of illness (p = 0.028) were positively correlated with mRNA levels. Genetic variation was not associated with mRNA or protein expression. Our data represent the first peripheral proteomic study of SELENBP1 in schizophrenia and suggest that plasma SELENBP1 protein is downregulated in patients with recent-onset schizophrenia.

Aims: The aims of this study were to conduct a meta-analysis and meta-regression to estimate the prevalence rates for obsessive compulsive symptoms (OCS) and obsessive compulsive disorder (OCD) in schizophrenia, and to investigate what influences these prevalence rates.Method: Studies were identified via an online OVID database search, including PsychInfo, Embase and Medline until December 2009.Results: Forty-three studies summarizing outcomes for 3978 subjects met inclusion criteria. The mean OCD prevalence is 12.3%, slightly increasing to 13.6% after adjustment in meta-regression. The prevalence rate of OCS, defined as any obsession or compulsion is 30.7% (30.3% adjusted). Higher severity of OCS, DIGS assessment, and Sub-Saharan African origin of study are associated with a lower OCS/OCD prevalence rate, use of DSM-IV edition, Y-BOCS assessment and longer schizophrenia history are associated with a higher prevalence rate.Conclusion: The prevalence of OCS and OCD in schizophrenia is substantial, specifically in more chronic patient populations and is influenced by the method of assessment. (C) 2013 Elsevier B. V. All rights reserved.

Aims: The aims of this study were to conduct a meta-analysis and meta-regression to estimate the prevalence rates for obsessive compulsive symptoms (OCS) and obsessive compulsive disorder (OCD) in schizophrenia, and to investigate what influences these prevalence rates. Method: Studies were identified via an online OVID database search, including PsychInfo, Embase and Medline until December 2009. Results: Forty-three studies summarizing outcomes for 3978 subjects met inclusion criteria. The mean OCD prevalence is 12.3%, slightly increasing to 13.6% after adjustment in meta-regression. The prevalence rate of OCS, defined as any obsession or compulsion is 30.7% (30.3% adjusted). Higher severity of OCS, DIGS assessment, and Sub-Saharan African origin of study are associated with a lower OCS/OCD prevalence rate, use of DSM-IV edition, Y-BOCS assessment and longer schizophrenia history are associated with a higher prevalence rate. Conclusion: The prevalence of OCS and OCD in schizophrenia is substantial, specifically in more chronic patient populations and is influenced by the method of assessment. (C) 2013 Elsevier B. V. All rights reserved.

This study examined the feasibility of providing motivational interviewing (MI) training to parents of young adults with recent-onset schizophrenia and co-occurring cannabis use. The training was offered in a mental health care setting as part of a family motivational intervention (FMI). Ninety-seven parents were randomly assigned to either FMI or routine family support (RFS). To obtain a measure of parent's MI skills at baseline and 3 months after they completed FMI, their role-play interactions with an actor portraying their child were coded. The coding method had satisfactory inter-rater reliability and internal consistency. At follow-up, parents in FMI showed significantly greater adherence to (p=.03) and competence in (p=.04) MI than parents in RFS. Parents in FMI also demonstrated significantly greater increases in expressing empathy (p=.01). These results demonstrate that FMI is a feasible method for increasing MI skills in parents. Additional research is needed to better understand the unique application of MI to parent-child interactions.? 2014.

Cognitive training (CT) and aerobic exercise have separately shown promise for improving cognitive deficits in schizophrenia. Aerobic exercise releases brain-derived neurotrophic factor, which promotes synaptic plasticity and neurogenesis. Thus, aerobic exercise provides a neurotrophic platform for neuroplasticity-based CT. The combination of aerobic exercise and CT may yield more robust effects than CT alone, particularly in the initial course of schizophrenia. In a pilot study, 7 patients with a recent onset of schizophrenia were assigned to Cognitive Training & Exercise (CT&E) and 9 to CT alone for a 10-week period. Posit Science programs were used for CT. Neurocognitive training focused on tuning neural circuits related to perceptual processing and verbal learning and memory. Social cognitive training used the same learning principles with social and affective stimuli. Both groups participated in these training sessions 2d/wk, 2h/d. The CT&E group also participated in an aerobic conditioning program for 30 minutes at our clinic 2d/wk and at home 2d/wk. The effect size for improvement in the MATRICS Consensus Cognitive Battery Overall Composite score for CT&E patients relative to CT patients was large. Functional outcome, particularly independent living skills, also tended to improve more in the CT&E than in the CT group. Muscular endurance, cardiovascular fitness, and diastolic blood pressure also showed relative improvement in the CT&E compared to the CT group. These encouraging pilot study findings support the promise of combining CT and aerobic exercise to improve the early course of schizophrenia.

Several theories propose that the primary cognitive impairment in schizophrenia concerns a deficit in the processing of external input information. There is also evidence, however, for impaired motor preparation in schizophrenia. This provokes the question whether the impaired motor preparation in schizophrenia is a secondary consequence of disturbed (selective) processing of the input needed for that preparation, or an independent primary deficit. The aim of the present study was to discriminate between these hypotheses, by investigating externally guided movement preparation in relation to selective stimulus processing. The sample comprised 16 recent-onset schizophrenia patients and 16 controls who performed a movement-precuing task. In this task, a precue delivered information about one, two or no parameters of a movement summoned by a subsequent stimulus. Performance measures and measures derived from the electroencephalogram showed that patients yielded smaller benefits from the precues and showed less cue-based preparatory activity in advance of the imperative stimulus than the controls, suggesting a response preparation deficit. However, patients also showed less activity reflecting selective attention to the precue. We therefore conclude that the existing evidence for an impairment of externally guided motor preparation in schizophrenia is most likely due to a deficit in selective attention to the external input, which lends support to theories proposing that the primary cognitive deficit in schizophrenia concerns the processing of input information. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

The aim of the presented study was to compare schizophrenia and schizoaffective patients early in the course of the disease with and without comorbid substance abuse disorder (SUD vs. NSUD) with regard to brain morphology. In a prospective design 41 patients (20 SUD vs. 21 NSUD) diagnosed as recent-onset schizophrenia or schizoaffective disorder consecutively admitted to hospital received standardized psychopathological evaluation (BPRS, SANS, MADRS, CGI, GAF) and MRI scanning with volumetric measurement of superior temporal gyrus (STG), amygdala-hippocampal complex, and cingulum. Patients with SUD (primarily cannabis) were significantly younger, predominantly male and had a lower socioeconomic status. Despite less attentional impairment (SANS subscore) and elevated anxiety/depression (BPRS subscore) in patients with SUD compared to NSUD, no other psychopathological differences could be detected. There were no differences in the assessed temporolimbic brain morphology between the two subgroups. In conclusion, in this study substance abuse in recent-onset psychosis had no effect on brain morphology and the earlier onset of psychosis in patients with comorbid SUD could not be explained by supposed accentuated brain abnormalities in temporolimbic regions. peerReviewed

The prevalence of obsessive-compulsive disorder in subjects with psychotic disorder is much higher than in the general population. The higher than chance co-occurrence has also been demonstrated at the level of subclinical expression of both phenotypes. Both extended phenotypes have been shown to cluster in families. However, little is known about the origins of their elevated co-occurrence. In the present study, evidence for a shared etiological mechanism was investigated in 3 samples with decreasing levels of familial psychosis liability: 987 patients, 973 of their unaffected siblings and 566 healthy controls. The association between the obsessive-compulsive phenotype and the psychosis phenotype c.q. psychosis liability was investigated. First, the association was assessed between (subclinical) obsessive-compulsive symptoms and psychosis liability. Second, in a cross-sib cross-trait analysis, it was examined whether (subclinical) obsessive-compulsive symptoms in the patient were associated with (subclinical) psychotic symptoms in the related unaffected sibling. Evidence was found for both associations, which is compatible with a partially shared etiological pathway underlying obsessive-compulsive and psychotic disorder. This is the first study that used a cross-sib cross-trait design in patients and unaffected siblings, thus circumventing confounding by disease-related factors present in clinical samples. ispartof: PLoS One vol:10 issue:6 ispartof: location:United States status: published

Background: Neurological abnormalities including a variety of subtle deficits such as discrete impairments in sensory integration, motor coordination, and sequencing of complex motor acts are frequently found in patients with schizophrenia and commonly referred to as neurological soft signs (NSS). Asperger-Syndrome (AS) is characterized by sensory-motor difficulties as well. However, the question whether the two disorders share a common or a disease-specific pattern of NSS remains unresolved. Method: A total of 78 age- and education-matched participants (26 patients with recent-onset schizophrenia, 26 individuals with AS, and 26 healthy controls) were recruited for the study. Analyses of covariance (ANCOVAs), with age, years of education and medication included as covariates, were used to examine group differences on total NSS and the five subscale scores. Discriminant analyses were employed to identify the NSS subscales that maximally discriminate between the three groups. Results: Significant differences among the three groups were found in NSS total score and on the five NSS subscales. The two clinical groups differed significantly in the NSS subscale „motor coordination. The correct discriminant rate between patients with schizophrenia and individuals with AS was 61.5%. The correct discriminant rate was 92.3% between individuals with AS and healthy controls, and 80.8% between schizophrenia patients and healthy controls, respectively. Conclusions: Our findings provide new evidence for the presence of NSS in AS and lend further support to previously reported difficulties in movement control in this disorder. According to the present results, schizophrenia and AS seem to be characterized by a different pattern of NSS.

Introduction: The co-occurrence of obsessive-compulsive disorder (OCD) in patients with schizophrenia and related disorders has been increasingly recognized. However, the rate of psychosis comorbidity in OCD patients has yet to be systematically evaluated. Methods: The prevalence of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychotic disorders was evaluated in 757 subjects consecutively referred to a specialised diagnostic and treatment facility for OCD. Demographic and clinical characteristics were assessed. Results: Thirteen OCD patients (1.7%) also met the DSM-IV criteria for a psychotic disorder. We found no significant differences in clinical characteristic between OCD patients with and without a psychotic disorder, although patients with OCD and a psychotic disorder more likely used illicit substances and more likely were male. Conclusion: Relatively few patients referred to a specialized treatment OCD center suffer from a psychotic disorder. CNS Spectr. 2009; 14(8):415-417

Diffusion MRI investigations in schizophrenia provide evidence of abnormal white matter (WM) microstructural organization as indicated by reduced fractional anisotropy (FA) primarily in interhemispheric, left frontal and temporal WM. Using tract-based spatial statistics (TBSS), we examined diffusion parameters in a sample of patients with severe chronic schizophrenia. Diffusion MRI data were acquired on 19 patients with chronic severe schizophrenia and 19 age- and gender-matched healthy controls using a 64 gradient direction sequence, (b = 1300 s/mm(2)) collected on a Siemens 1.5T MRI scanner. Diagnosis of schizophrenia was determined by Diagnostic and Statistical Manual for Mental Disorders 4th Edition (DSM-IV) Structured Clinical Interview for DSM disorder (SCID). Patients were treatment resistance, having failed to respond to at least two antipsychotic medications, and had prolonged periods of moderate to severe positive or negative symptoms. Analysis of diffusion parameters was carried out using TBSS. Individuals with chronic severe schizophrenia had significantly reduced FA with corresponding increased radial diffusivity in the genu, body, and splenium of the corpus callosum, the right posterior limb of the internal capsule, right external capsule, and the right temporal inferior longitudinal fasciculus. There were no voxels of significantly increased FA in patients compared with controls. A decrease in splenium FA was shown to be related to a longer illness duration. We detected widespread abnormal diffusivity properties in the callosal and temporal lobe WM regions in individuals with severe chronic schizophrenia who have not previously been exposed to clozapine. These deficits can be driven by a number of factors that are indistinguishable using in vivo diffusion-weighted imaging, but may be related to reduced axonal number or packing density, abnormal glial cell arrangement or function, and reduced myelin.

OBJECTIVE: Studies have linked cognitive functioning to everyday social functioning in psychotic disorders, but the nature of the relationships between cognition, social cognition, symptoms, and social functioning remains unestablished. Modelling the contributions of non-social and social cognitive ability in the prediction of social functioning may help in more clearly defining therapeutic targets to improve functioning. METHOD: In a sample of 745 patients with a non-affective psychotic disorder, the associations between cognition and social cognition at baseline on the one hand, and self-reported social functioning three years later on the other, were analysed. First, case-control comparisons were conducted; associations were subsequently further explored in patients, investigating the potential mediating role of symptoms. Analyses were repeated in a subsample of 233 patients with recent-onset psychosis. RESULTS: Information processing speed and immediate verbal memory were stronger associated with social functioning in patients than in healthy controls. Most cognition variables significantly predicted social functioning at follow-up, whereas social cognition was not associated with social functioning. Symptoms were robustly associated with follow-up social functioning, with negative symptoms fully mediating most associations between cognition and follow-up social functioning. Illness duration did not moderate the strength of the association between cognitive functioning and follow-up social functioning. No associations were found between (social) cognition and follow-up social functioning in patients with recent-onset psychosis. CONCLUSIONS: Although cognitive functioning is associated with later social functioning in psychotic disorder, its role in explaining social functioning outcome above negative symptoms appears only modest. In recent-onset psychosis, cognition may have a negligible role in predicting later social functioning. Moreover, social cognition tasks may not predict self-reported social functioning. ispartof: Plos One vol:11 issue:4 ispartof: location:United States status: published

Long-acting injectable antipsychotics (LAIs) were developed to make treatment easier, improve adherence, and/or signal the clinician when nonadherence occurs. Second-generation antipsychotic LAIs (SGA-LAIs) combine the advantages of SGA with a long-acting formulation. The purpose of this review is to evaluate the available literature concerning the impact of SGA-LAIs on patient functioning and quality of life (QOL). Although several studies regarding schizophrenia patients' functioning and QOL have been performed, the quantity of available data still varies greatly depending on the SGA-LAI under investigation. After reviewing the literature, it seems that SGA-LAIs are effective in ameliorating patient functioning and/or QOL of patients with schizophrenia, as compared with placebo. However, while methodological design controversy exists regarding the superiority of risperidone LAI versus oral antipsychotics, the significant amount of evidence in recently published research demonstrates the beneficial influence of risperidone LAI on patient functioning and QOL in stable patients and no benefit over oral treatment in unstable patients. However, the status of the research on SGA-LAIs is lacking in several aspects that may help physicians in choosing the correct drug therapy. Meaningful differences have been observed between SGA-LAIs in the onset of their clinical efficacy and in the relationships between symptoms and functioning scores. Moreover, head-to-head studies comparing the effects of SGA-LAIs on classical measures of psychopathology and functioning are available mainly on risperidone LAI, while those comparing olanzapine LAI with other SGA-LAIs are still lacking. Lastly, some data on their use, especially in first-episode or recent-onset schizophrenia and in refractory or treatment-resistant schizophrenia, is available.

Introduction: The co-occurrence of obsessive-compulsive disorder (OCD) in patients with schizophrenia and related disorders has been increasingly recognized. However, the rate of psychosis comorbidity in OCD patients has yet to be systematically evaluated.Methods: The prevalence of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychotic disorders was evaluated in 757 subjects consecutively referred to a specialised diagnostic and treatment facility for OCD. Demographic and clinical characteristics were assessed.Results: Thirteen OCD patients (1.7%) also met the DSM-IV criteria for a psychotic disorder. We found no significant differences in clinical characteristic between OCD patients with and without a psychotic disorder, although patients with OCD and a psychotic disorder more likely used illicit substances and more likely were male.Conclusion: Relatively few patients referred to a specialized treatment OCD center suffer from a psychotic disorder.

The aim of this study was to see whether and how cognition predicts outcome in recent-onset schizophrenia in a large range of domains such as course of illness, self-care, interpersonal functioning, vocational functioning and need for care. At inclusion, 115 recent-onset patients were tested on a cognitive battery and 103 patients participated in the follow-up 2 years after inclusion. Differences in outcome between cognitively normal and cognitively impaired patients were also analysed. Cognitive measures at inclusion did not predict number of relapses, activities of daily living and interpersonal functioning. Time in psychosis or in full remission, as well as need for care, were partly predicted by specific cognitive measures. Although statistically significant, the predictive value of cognition with regard to clinical outcome was limited. There was a significant difference between patients with and without cognitive deficits in competitive employment status and vocational functioning. The predictive value of cognition for different social outcome domains varies. It seems that cognition most strongly predicts work performance, where having a cognitive deficit, regardless of the nature of the deficit, acts as a rate-limiting factor. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

Objective: The aim of this study was to test the goodness-of-fit of all previously published five-factor models of the Positive and Negative Syndrome Scale (PANSS).Methods: We used confirmatory factor analysis (CFA) with a large data set (N = 5769).Results: The different subsamples were tested for heterogeneity and were found to be homogeneous. This indicates that despite variability in age, sex, duration of illness, admission status. etc.. in the different subsamples, the structure of symptoms is the same for all patients with schizophrenia. Although previous research has shown that a five-factor model fits the data better than models with three or four factors. no satisfactory fit for any of the 25 published five-factor models was found with CFA.Conclusions: Variability in age, sex, admission status and duration of illness has no substantial effect on the structure of symptoms in schizophrenia. The lack of fit can be caused by ill-defined items that aim to measure several properties in a single rating. Another explanation is that well-defined symptoms can have two or more causes. Then a double or triple loading item should not be discarded, but included because the complexity of symptoms in schizophrenia is represented by these multiple loadings. Such a complex model not only needs confirmation by CFA, but also has to be proven stable. A 10-fold cross-validation is suggested to develop a complex and stable model. (c) 2006 Elsevier B.V All rights reserved.