Clinical Characteristics Of Schizophrenia Research Articles

Sex effects on DNA methylation affect discovery in epigenome-wide association study of schizophrenia.

Sex differences in the epidemiology and clinical characteristics of schizophrenia are well-known; however, the molecular mechanisms underlying these differences remain unclear. Further, the potential advantages of sex-stratified meta-analyses of epigenome-wide association studies (EWAS) of schizophrenia have not been investigated. Here, we performed sex-stratified EWAS meta-analyses to investigate whether sex stratification improves discovery, and to identify differentially methylated regions (DMRs) in schizophrenia. Peripheral blood-derived DNA methylation data from 1519 cases of schizophrenia (male n = 989, female n = 530) and 1723 controls (male n = 997, female n = 726) from three publicly available datasets, and the TOP cohort were meta-analyzed to compare sex-specific, sex-stratified, and sex-adjusted EWAS. The predictive power of each model was assessed by polymethylation score (PMS). The number of schizophrenia-associated differentially methylated positions identified was higher for the sex-stratified model than for the sex-adjusted one. We identified 20 schizophrenia-associated DMRs in the sex-stratified analysis. PMS from sex-stratified analysis outperformed that from sex-adjusted analysis in predicting schizophrenia. Notably, PMSs from the sex-stratified and female-only analyses, but not those from sex-adjusted or the male-only analyses, significantly predicted schizophrenia in males. The findings suggest that sex-stratified EWAS meta-analyses improve the identification of schizophrenia-associated epigenetic changes and highlight an interaction between sex and schizophrenia status on DNA methylation. Sex-specific DNA methylation may have potential implications for precision psychiatry and the development of stratified treatments for schizophrenia.

The <i>CRP</i> Gene’s Role in the Relations between Childhood Adversity and History of Suicide Attempts in Schizophrenia

Research suggests that, in contrast to circulating C-reactive protein (CRP), genetic variants conferring higher CRP levels have protective effects against schizophrenia and moderate influences of season of birth on the development of the disease. This study aimed to explore whether the CRP gene also moderates the relations between childhood adversity and clinical characteristics of schizophrenia. The relations between childhood adversity, genotypes at rs2794521within the CRP locus, syndromes measured as five factors and two negative subfactors of the Positive and Negative Syndrome Scale, and history of suicide attempts were analyzed in 921 schizophrenia patients using analyses of covariances, Pearson’s chi-squared test, and logistic regression. A significant effect of genotype on suicide attempts in patients exposed to childhood adversity was found. The result suggests a moderating role of genetic determinants of inflammation in translating early life psychological stress effects into risk of suicide attempts in schizophrenia.

Association of negative symptom domains and other clinical characteristics of schizophrenia on long-term hospitalization.

Background:Recent studies suggest five domains for negative schizophrenia symptoms: anhedonia, asociality, avolition, blunted affect, and alogia. Avolition has been considered a characteristic symptom in community-dwelling patients. However, few studies have explored the association of these symptoms with long-term hospitalization.Purpose:This study explored the relative association of each of the five domains of negative symptoms in two groups of patients with schizophrenia: long-term hospitalized and community-dwelling patients.Methods:Participants included 56 long-term inpatients and 111 community-dwelling patients at Nasukougen Hospital in Japan. The nearest neighbor matching within caliper was used. After matching participants by age, sex, disease duration, and years of education, each group was assigned 30 participants. Model 1 was analyzed with a logistic regression analysis with 5 subdomains as independent variables. Model 2 was analyzed after adding positive symptoms, cognitive function, functional skills, and functional outcomes to the subdomains that were significant in model 1.Results:The results indicated that asociality was significantly associated with long-term hospitalization. When the characteristic clinical factors of schizophrenia were added, asociality, daily living skills, and social and role functions were found to be characteristic of long-term hospitalization. Among the negative symptoms, lack of social motivation was more characteristic among the group with a poor prognosis.Conclusions:Of the negative symptoms associated with long-term hospitalization, asociality, lack of social motivation, rather than avolition was found to be most strongly associated with community-dwelling patients’ functional outcomes. Further studies are required to establish a causal association as it may have therapeutic implications.

The association between chronotype and sleep quality, and cardiometabolic markers in patients with schizophrenia

ABSTRACT Current data on chronotype and sleep quality and their relationship with clinical characteristics of schizophrenia are insufficient to evaluate whether these variables are associated with cardiometabolic risk. We aimed to identify the interplay between chronotype, sleep quality and metabolic indices that can potentially predict negative cardiometabolic outcomes in schizophrenia patients. One-hundred schizophrenia patients who were under a stable antipsychotic regime were enrolled in the study. Clinical information, anthropometric measurements, as well as recent metabolic parameters including serum lipids, atherogenic, and metabolic indices suggestive of cardiometabolic risk were recorded. High and low sleep quality groups (HSQ and LSQ) were determined via the Pittsburgh Sleep Quality Index and chronotypes were evaluated with the Morningness–Eveningness Questionaire. Patients with eveningness chronotype had poorer sleep quality compared to intermediate or morningness (p = .017) patients. The LSQ group had higher total cholesterol (p = .004) and low-density lipoprotein (LDL) (p = .041) compared to the HSQ group. Mean blood pressure was higher in the eveningness chronotype patients compared to intermediate or morningness patients (p = .015). According to a logistic regression model, total cholesterol, disposition index, and having an eveningness chronotype significantly predicted LSQ in schizophrenia. Eveningness chronotype may lead to impaired cardiometabolic regulation with the mediation of poor sleep quality in schizophrenia patients. Cardiovascular diseases, sleep quality, and sleep patterns can influence each other; thus, this complex relationship in schizophrenia should be considered while configuring both pharmacological and behavioral interventions.

The Association Between Cognitive Deficits and Clinical Characteristic in First-Episode Drug Naïve Patients With Schizophrenia.

Background: Schizophrenia is a severe mental disease which characterized by positive symptom, negative symptom, general pathology syndrome and cognitive deficits. In recent years, many studies have investigated the relationship between cognitive deficits and clinical characteristics in schizophrenia, but relatively few studies have been performed on first-episode drug-naïve patients.Methods: Eighty seven first-episode drug-naïve schizophrenia patients were assessed for positive symptom, negative symptom, general pathology symptom and cognitive deficits from the Positive and Negative Symptom Scale and MATRICS Consensus Cognitive Battery. Psychotics depression were assessed using the Calgary depressing scale for schizophrenia. The relationship between clinical characteristics and cognitive deficits were assessed using correlation analysis and linear regression analysis.Results: The prevalence of cognitive deficits among the patients in our study was 85.1% (74/87) which was much higher than that in the general population. According to correlation analysis, negative symptom was negatively correlated with speed of processing and social cognition, and general pathology showed a negative correlation with attention/vigilance. In addition, a positive correlation was found between age and speed of processing. No correlation was found between cognitive deficits and positive symptom.Conclusions: This study confirmed that negative symptom is negatively related with some domains of cognitive function in first-episode drug naïve schizophrenia patients.Trail Registration: NCT03451734. Registered March 2, 2018 (retrospectively registered).

Hair Cortisol Is Associated With Social Support and Symptoms in Schizophrenia.

IntroductionPsychosocial stressors may worsen psychotic symptoms in schizophrenia, while social support could protect against the effects of stress in schizophrenia. Hypothalamus-pituitary-adrenal axis dysfunction has been associated with schizophrenia. Hair cortisol concentrations (HCC) allow assessment of cumulative cortisol secretion over the preceding 3 months. The relationship between HCC, psychosocial stressors, social support, and the clinical characteristics of schizophrenia needs to be explored.MethodsOne hundred nine schizophrenia patients and 86 healthy controls between the ages of 18 and 60 were enrolled in the study. Three-centimeter samples of hair were collected from the scalp and HCC were measured using ELISA kits. Linear regression and factor analysis were employed to examine the relationship between HCC, childhood trauma, the number of stressful life events (SLE), the amount of social support in the 3 months prior to the hair cortisol assessment and clinical characteristics of schizophrenia.ResultsSchizophrenia patients experience more SLE in their lifetime, receive less social support, and have lower HCC in the recent 3 months compared to healthy controls. In the schizophrenia patients, HCC are positively associated with the amount of social support and negatively associated with the severity of delusions. The interaction between social support and SLE predicts decreased HCC. Factor analysis shows that a subgroup of schizophrenia patients who experience childhood trauma and SLE are characterized by decreased HCC.ConclusionsFindings indicate social support could be a moderator for the relationship between SLE and HCC which may attenuate the effects of SLE in schizophrenia.

Effect of the C-reactive protein gene on risk and clinical characteristics of schizophrenia in winter-born individuals

C-reactive protein (CRP) levels are elevated in a subset of schizophrenia patients and correlated with more severe symptoms, which makes CRP a potential theranostic biomarker for the disease. However, genotypes associated with higher CRP concentrations have the protective effect against schizophrenia. To resolve this discrepancy, more research on the role of CRP in schizophrenia is needed. The present study aimed to investigate the effects on schizophrenia of the CRP gene in combination with season of birth (SOB), the known risk factor for the disease. We first examined the impact of seasonality on schizophrenia risk in the Russian population, using samples of 2452 patients and 1203 controls, and then assessed the CRP rs2794521 polymorphism × SOB interaction effect on the disease risk, age-of-onset and symptoms severity in 826 patients and 476 controls. An excess of winter births in patients was not significant. At the same time, we found that winter-born patients carrying the CRP GG genotype, which is associated with low transcriptional activity, had an earlier age at onset than the other patients. The findings are in line with the protective role of high active CRP genetic variants in the development of schizophrenia and provide support for the hypothesis that this effect of CRP takes place early in life.

Effect of the ZNF804A Gene and Obstetrical Complications on Clinical Characteristics of Schizophrenia

To explore for the first time an effect of gene × environment (G × E) interactions on the clinical characteristics of schizophrenia, we studied the ZNF804A rs1344706 polymorphism, a genome-wide supported risk variant of psychosis, and obstetrical complications (OC) as a risk-modifying factor for psychiatric disorders, in 369 patients with schizophrenia (203 women, mean age 29.7 ± 10.1 years, age at disease onset 21.6 ± 7.3 years). A history of at least one definite OC was present in 111 patients, while 258 patients had no history of OC. Clinical characteristics, including age at disease onset and severity of symptoms assessed with PANSS, were compared by the ZNF804A genotype in the groups with and without OC. Patients with the risk AA genotype and OC had higher scores on the subscale of general psychopathological symptoms compared to the carriers of the CC genotype without OC (p = 0.007). The results demonstrated an additive effect of ZNF804A rs1344706 and OC on symptoms severity in schizophrenia.

Subsyndromal and syndromal depressive symptoms among older adults with schizophrenia spectrum disorder: Prevalence and associated factors in a multicenter study

BackgroundFew studies have examined the prevalence and correlates of subsyndromal and syndromal depressive symptoms (SSSD) among older adults with schizophrenia spectrum disorder. In this report, we examined the prevalence of SSSD and their associations with sociodemographic characteristics, clinical characteristics of schizophrenia, comorbidity, psychotropic medications, quality of life, functioning and mental health care utilization in a large, multicenter sample of older adults with schizophrenia spectrum disorder. MethodsData from the Cohort of individuals with Schizophrenia Aged 55 years or more (CSA) were used to examine the prevalence of SSSD, defined using the Center of Epidemiologic Studies Depression (CESD) scale. Clinical characteristics associated with SSSD were explored. ResultsAmong 343 older adults with schizophrenia spectrum disorder, 78.1% had either subsyndromal (30.6%) or syndromal (47.5%) depressive symptoms. SSSD were independently associated with positive and negative symptoms, lower quality of life, non-late-onset psychosis, benzodiazepine use and urbanicity. There were no significant associations of SSSD with other sociodemographic characteristics and psychotropic medications, or with general medical conditions. We found no significant differences in the proportion of participants who were treated with antidepressants between those with syndromal depressive symptoms and those without depression (22.1% vs. 20.0%, p = 0.89). SSSD were not associated with higher mental health care utilization. LimitationsData were cross-sectional and depression was not evaluated with a semi-structured interview. ConclusionSSSD may be highly prevalent and under-assessed and/or undertreated among older adults with schizophrenia spectrum disorder. Our findings should alert clinicians about the need to assess systematically and regularly depression in this vulnerable population.

Comparison of serum essential trace metals between patients with schizophrenia and healthy controls

Preclinical and clinical studies have suggested that essential trace metals (ETMs) play an important role in the pathophysiology of brain-based disorders, including schizophrenia. This case-control study aimed to evaluate the association between ETMs and schizophrenia, and to further examine the association between ETMs and clinical characteristics in schizophrenia. One-hundred and five (n = 105) subjects who meet DSM-IV criteria for schizophrenia between the ages of 18 and 40 were recruited for the study. One hundred and six (n = 106) age- and sex-matched healthy controls (HCs) were recruited for comparison. Serum concentrations of seven ETMs [i.e. iron (Fe), zinc (Zn), copper (Cu), cobalt (Co), manganese (Mn), nickel (Ni) and molybdenum (Mo)] were evaluated using inductively coupled plasma mass spectrometry, which allows for the quantitative analysis of multiple ETMs at a single time point. Compared to HCs, serum concentrations of Mn and Mo were significantly lower in patients with schizophrenia. In contrast, serum concentrations of Fe and Ni were significantly higher in patients with schizophrenia. Additionally, correlations between specific ETMs and metabolic parameters (particularly those related to liver and renal function) were found in patients with schizophrenia, and the correlations between every two ETMs in HCs were widely interrupted. Differential levels of selected ETMs (i.e., Mn, Mo, and Ni) were identified between patients with schizophrenia and HCs following adjustment for potential confounders. The findings here should therefore be evaluated in future studies.

Sluggishness of Early-Stage Face Processing (N170) Is Correlated with Negative and General Psychiatric Symptoms in Schizophrenia.

Patients with schizophrenia consistently exhibit abnormalities in the N170 event-related potential (ERP) component evoked by images of faces. However, the relationship between these face-specific N170 abnormalities in patients with schizophrenia and the clinical characteristics of this disorder has not been elucidated. Here, ERP recordings were conducted for patients with schizophrenia and healthy controls. The amplitude and latency of the N170 component were recorded while participants passively viewed face and non-face (table) images to explore the correlation between face-specific processing and clinical characteristics in schizophrenia. The results provided evidence for a face-specific N170 latency delay in patients with schizophrenia. The N170 latency in patients with schizophrenia was significantly longer than that in healthy controls when images of faces were presented in both upright and inverted orientations. Importantly, the face-related N170 latencies of the left temporo-occipital electrodes (P7 and PO7) were positively correlated with both negative and general psychiatric symptoms in these patients. The N170 amplitudes were weaker in patients than in controls for inverted images of both faces and non-faces (tables), with a left-hemisphere dominance. The face inversion effect (FIE), meaning the difference in N170 amplitude between upright and inverted faces, was absent in patients with schizophrenia, suggesting an abnormality of holistic face processing. Together, these results revealed a marked symptom-relevant neural delay associated with face-specific processing in patients with schizophrenia, providing additional evidence to support the demyelination hypothesis of schizophrenia.

The confirmatory factor structure of neurological soft signs in Nigerians with first episode schizophrenia

We describe empirically derived categories of NSS in first episode schizophrenia among indigenous Africans. A total of 84 Nigerian patients with the disease were assessed using the neurological evaluation scale. An exploratory factor analysis with orthogonal varimax rotation was first conducted and the factors derived based on a priori criteria were subjected to confirmatory analyses using SPSS 18.0 and AMOS 18.0. We tested four different competing models to identify the structure with the best fit to the data. The relationship of the derived NSS structure with the clinical characteristics of schizophrenia was then explored using the Pearson correlation method. The overall clinical status was assessed using the positive and negative syndrome scale and clinical global impression. Additional assessments included the pre-morbid adjustment scale and calgary depression scale for schizophrenia. A three factor structure in which stereognosis is prescribed to load into a ‘perceptual and motor sequencing’ category (audio–visual integration, fist-edge palm, rhythm tapping, extinction, right–left confusion) provided the best fit to the data (chi-square goodness of fit test=1.25; comparative fit index=0.95; root square means error of approximation <0.05). The other two factors were: ‘eye movement’ (synkinesis, convergence, gaze impersistence) and ‘motor co-ordination and graphaesthesia’ (Tandem walk, adventitious flow, graphaesthesia). The signs were associated with severe negative (r=0.456, p<0.001), and disorganization (r=0.559, p<0.001) psychopathologies. NSS in this sample are heterogeneous, but aggregates into three correlated categories with significant overlap with previously described classifications.

Association study between the MDR1 gene and clinical characteristics in schizophrenia.

Schizophrenia is a complex psychiatric disorder, characterized by disturbed patterns of thought and affecting 0.3-2.0% of the world population. Previously, the multidrug resistance 1 (MDR1) gene has been associated with schizophrenia in treatment response studies in psychotic patients. The aim of this study was to determine the association between MDR1 gene polymorphisms and clinical characteristics in patients with schizophrenia. Positive and negative symptoms of schizophrenia were assessed with the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) in 158 Mexican patients with schizophrenia. Analyses of MDR1 gene polymorphisms were performed using TaqMan technology. A multivariate ANOVA was performed with MDR1 polymorphisms and gender as independent variables. Males with the G/G genotype of MDR1 rs2032582 presented significantly higher levels of delusions (p = 0.02). When comparing female vs. male groups, the difference was statistically significant (p = 0.0003). Analyses of the MDR1 gene rs1045642 variant showed no significant differences. Our findings suggest that male carriers of the G allele of variant rs2032582 exhibit greater severity of delusions; however, these results should be taken as preliminary, and replication studies in other populations of different ethnic origins are required to confirm these findings.

Association of microRNA137 gene polymorphisms with age at onset and positive symptoms of schizophrenia in a Han Chinese population.

MicroRNA137 (miRNA137) regulates several gene expressions involved in brain development, and a recent large genome wide association study (GWAS) revealed a possible association between miRNA137 and schizophrenia. The allelic variants of rs66642155, a variable number tandem repeat polymorphism, and the single nucleotide polymorphism rs1625579 A/C in the miRNA137 host gene fragment were compared between 300 schizophrenic patients and 300 healthy controls from the Han Chinese population. The association of these polymorphisms with clinical characteristics of schizophrenia was also tested. Genotype and allele frequencies of these polymorphisms were not significantly different between patient and control populations. In patients, however, age at onset was much later in wild type rs66642155 carriers than in mutation carriers. Total positive score on the Positive and Negative Symptom Scale (PANSS), total five-factor model positive score, and the delusions symptom score were all significantly higher in wild type rs66642155 carriers with schizophrenia, while the disturbance of volition symptom score was significantly higher in the mutation carriers with schizophrenia. MiRNA137 may not be a significant susceptibility gene for schizophrenia, but in patients, rs66642155 allelic variant of miRNA137 appears to influence age at onset and the severity of positive symptoms.

C-reactive protein serum level in drug-free male Egyptian patients with schizophrenia

Despite the growing research interest in the role of immunological markers in schizophrenia, few studies, with conflicting results, have focused on the association between high sensitivity C-reactive protein (hs-CRP) levels and clinical characteristics in schizophrenia. In this cross-sectional case–control study, a sample of 200 antipsychotic-free male Egyptian schizophrenia patients was assessed by the Positive and Negative Syndrome Scale (PANSS) and compared with 200 healthy controls as regards serum hs-CRP level using an immunoturbidimetric method. CRP level for patients (geometric mean=3.3mg/L) was significantly (P=0.000) higher than that for controls (geometric mean=1.4mg/L). PANSS scores and patients' data, which significantly correlated with serum hs-CRP level, were entered into a stepwise multiple regression analysis. Results of this analysis showed that PANSS negative symptom score was second only to the waist circumference, with which they explained 54.7 % of the variation in serum hs-CRP. Comparable results were obtained when patients, controls and the relevant confounders were included in one multivariate analysis. We concluded that in Egyptian men, waist circumference and schizophrenia diagnosis are strong predictors of raised CRP level independent of a number of potentially confounding variables. In antipsychotic-free patients, CRP level is higher than in healthy controls and is positively correlated with the severity of the psychopathology as measured by PANSS. This relationship is especially notable in negative, but not positive symptoms.

Demographic and Clinical Characteristics in Schizophrenia: A multi-center cross-sectional case record study

The aim of the present study is to assess the relationship between demographic characteristics and suicide attempts, physically aggressive behavior, substance abuse, repeated hospitalizations, and continuous illness course . The medical records of patients from three different treatment centers were assessed. The relationship between demographics and clinical characteristics were assessed. Logistic regression analysis was conducted to determine the predicting factors for suicide attempts, physically aggressive behavior, heavy smoking, repeated hospitalizations, and continuous illness course. The medical records of a total of 720 patients with schizophrenia were assessed. Of these patients, 68% were never married, 56% were unemployed, and 69% were living with their parents. 35% of the patients had a relative diagnosed with a psychotic disorder. The mean age for the onset of the illness was found to be 23.5, with no difference between females and males. 50% of the patients had had repeated hospitalizations. The duration of untreated psychosis was 10.8 months and 28% of the patients had been through a continuous course of the illness. 57% of the patients were found to be regular smokers; 55% of the patients had physically aggressive behavior; 52% had experienced a suicidal ideation and attempt; 28% had made at least one suicide attempt. The percentage of patients having had a legal issue related to their illness was 11%. Heavy smoking was predicted with the continuous illness and male gender. Physically aggressive behavior was predicted with suicide ideation and attempts, being single, having insufficient family support, and having undergone frequent hospitalization. Repeated hospitalizations were predicted with suicide attempts and having a legal problems; continuous course of illness was predicted with being unemployed and lack of family support; suicide attempt was predicted with duration of the illness. When both sexes were compared, the lack of difference at the onset of disease between the two suggests that there might be other factors playing a role in this phenomenon. The relationship between suicidal ideation and behavior and physical aggressive behavior, indicates that these two might share common underlying mechanisms. Possible significant relationships between demographic and clinical characteristics should be kept in mind for the prevention, treatment, and rehabilitation approaches in dealing with schizophrenia.

Dysbindin and D-Amino-Acid-Oxidase Gene Polymorphisms Associated with Positive and Negative Symptoms in Schizophrenia

Background: Schizophrenia is a genetically complex disorder with an unknown pathophysiology. Several genes implicated in glutamate metabolism have been associated with the disorder. Recent studies of polymorphisms in the dystrobrevin-binding protein 1 gene (DTNBP1; dysbindin) and D-amino-acid-oxidase (DAO) gene, both involved in glutamate receptor function, reported associations with negative symptoms and with anxiety and depression, respectively, when measured with the Positive and Negative Syndrome Scale (PANSS). Methods: In the present study, the suggested association between dysbindin and DAO single nucleotide polymorphisms (SNPs) and PANSS scores was analyzed in 155 Norwegian schizophrenia patients. Results: There was a significant association between the dysbindin SNP rs3213207 and severity of both negative symptoms and total symptom load, as well as between the DAO SNP rs2070587 and total symptom score and severity of anxiety and depression. Conclusion: The present association of dysbindin SNPs with negative symptoms and DAO SNPs with anxiety and depression is a replication of earlier findings and strengthens the hypothesis of a genetic association. It further indicates involvement of glutamate abnormalities in schizophrenia pathophysiology, as suggested by previous studies, and suggests that polymorphisms may be associated with subgroups of clinical characteristics in schizophrenia.

Views of Persons With Schizophrenia on Their Own Disorder: An Italian Participatory Study

This study explored the views of 241 patients with schizophrenia about their own disorder. Patients' knowledge of their diagnosis, confidence that they will be well again, and perception of limitations in their own life as a result of the disorder were explored in relation to patients' opinions about the social consequences of schizophrenia. Study results were presented to participants, and suggestions were collected regarding how these study results should be used. Seventy-two respondents (30%) reported that a psychiatrist told them that they have schizophrenia. Respondents who were confident that they would be well again had a lower duration of contact with psychiatric services and a less pronounced perception of affective and social difficulties related to schizophrenia. Respondents who did not feel limited in their life by the disorder reported less social distance and more optimism about the usefulness of treatments. Participatory studies may provide ideas for a more constructive interaction between patients and professionals.

Dysbindin gene variants are associated with bipolar I disorder in a Korean population

The dysbindin gene ( DTNBP1) has been associated with schizophrenia in several populations. Because the clinical characteristics of schizophrenia and bipolar disorder overlap in many respects and findings from genetic studies have suggested common genes between them, we conducted a case control association study of bipolar disorder in Korea to investigate the genetic association between DTNBP1 and bipolar disorder. In total, 163 patients with bipolar disorder and 350 controls were evaluated. We genotyped three single nucleotide polymorphisms of DTNBP1 (SNP A, P1763, and P1320) and analyzed the allele, genotype, and haplotype associations with bipolar disorder. We found significant genotypic associations with P1763 and P1320, but no association with SNP A in the bipolar I group. When we included bipolar II and schizoaffective disorder in the affected phenotype, the significance decreased. A positive association was observed between the SNP A-P1763 haplotype and the bipolar I phenotype. This haplotype association was lost when we either broadened our phenotype or included P1320 in a haplotype. The positive results of the present study lost significance after a Bonferroni correction for multiple testing. These findings are consistent with previous findings that showed a positive association of DTNBP1 with bipolar disorders. Moreover, our results suggest that DTNBP1 may contribute more to bipolar I disorder than bipolar II disorder or schizoaffective disorder. Further comprehensive studies will be required to clarify these association, however, it seems likely that DTNBP1 is a susceptibility gene for bipolar disorder.

Perception of patients’ unpredictability and beliefs on the causes and consequences of schizophrenia

The belief that mental disorders involve a high risk of unpredictable behaviours is a factor which influences negatively the social acceptance of the mentally ill. In this paper, we compare the beliefs about the causes and psychosocial consequences of schizophrenia expressed by 536 respondents who had the firm conviction that patients with schizophrenia are unpredictable and by 457 respondents who firmly believed that they are not. The survey was conducted in 30 Italian geographic areas, randomly selected taking into account their location and population density. The data were collected by the Questionnaire about Opinions on Mental Illness (QO). Respondents who believed that patients with schizophrenia are unpredictable reported more frequently factors such as use of alcohol and drugs and frequenting bad company as being involved in the development of the disorder. In addition, this group showed more restrictive opinions about patients' civil and affective rights. Low education was found to be significantly associated with perception of "unpredictability" in schizophrenia. These results suggest the need to: a). inform the general public on the main clinical characteristics of schizophrenia and on the risk of unpredictable behaviours in the acute phases of this mental disorder; b). carry out sensitisation campaigns against discrimination toward people with schizophrenia emphasising successful experiences of social integration.