A Hindi version of the Diagnostic Interview for Genetic Studies

Executive functions and cognitive deficits in schizophrenia: comparisons between probands, parents and controls in India

BACKGROUND

Cognitive impairment is said to be a core feature of schizophrenia. Executive function is an important cognitive domain.

AIM

This study was undertaken to assess cognitive impairment among Indian patients with schizophrenia (Sz) or schizoaffective disorder (SzA), compared with their parents and unaffected individuals (controls).

SETTINGS AND DESIGN

Executive functions as measured by Trail-making Test (TMT), of patients and their parents were compared with controls. The patients were recruited from the Outpatients' Department (OPD) of a government hospital.

MATERIALS AND METHODS

Patients diagnosed as Sz or SzA (n=172) and their parents (n=196: families n=132, 119 fathers and 77 mothers) participated. We also included 120 persons with no history of psychiatric illness. Cognitive function was assessed with the TMT. The Information Score of the Post Graduate Institute Battery of Brain Dysfunction test, developed in India for Indian subjects was used as a proxy for general fixed knowledge.

STATISTICAL ANALYSIS

Logistic and linear regression was used to compare cognitive deficits of cases, parents and controls.

RESULTS

Cases and their parents took significantly more time than controls on Part B of the TMT. There were no statistically significant differences between cases and parents on any of the TMT parameters. Using regression analysis, the most significant correlates of all TMT parameters among cases were with occurrence of auditory hallucinations and current age.

CONCLUSION

Cases, as well as their parents showed more cognitive impairment than controls on the TMT.

Correlates of response to Olanzapine in a North Indian Schizophrenia sample

Olanzapine is widely used for the treatment of schizophrenia and is considered a first line medication in India. Along with other factors, the variation in response and side effects to this agent may be accounted for by genetic differences among patients. Olanzapine was administered for 6 weeks to Indian subjects with schizophrenia or schizoaffective disorder (DSM-IV, n=130), as part of an open label study. Intent-to-treat analysis was performed, and 10 polymorphic markers from seven genes (dopamine D1, D2, D3 and D4 receptors, serotonin 2A receptor and the drug-metabolizing enzymes (CYP1A2 and CYP2D6)), together with demographic and clinical variables, were analyzed as potential predictors of response. Olanzapine was efficacious, but significant weight gain was noted. Baseline weight and a 120 bp deletion polymorphism at the dopamine receptor D4 (DRD4) gene were associated with changes in symptom scores. Predictable covariates of treatment response were also noted. These results merit replicate studies.

Is familiality associated with downward occupation drift in schizophrenia?

OBJECTIVE

Downward occupational drift has been extensively investigated in schizophrenia. It is known that certain illness related factors, such as severity, affect drift, but the impact of familial factors has not been investigated.

METHODS

Occupation drift was studied among patients with schizophrenia/schizoaffective disorder (SZ/SZA)(n=523) and 130 affected sib pairs (ASPs). Drift was analyzed in relation to familiality as well as demographic and clinical variables. For comparison one proband (one of the affected siblings) from each ASP was selected. Occupation drift was measured in relation to the most responsible job held, and with regard to head of the household (HOH) occupation status.

RESULTS

There was no significant difference between single affected and ASP probands in terms of occupational drift from the most responsible job (drifted 39.2% and 38% respectively) and with regard to HOH's occupation (drifted 88% and 82.8% respectively). A significant part of the sample remained unemployed in both single affected and ASP samples. Thus, there was no significant impact of familiality on these variables. However, marital status, pattern of severity, age at onset, gender were found to be associated with downward occupation drift in single affected probands while the only significant factor in familial probands was pattern of severity of severity when measuring in terms of downward drift from most responsible job.

CONCLUSION

Though there is occupation drift in schizophrenia, there is no detectable impact of familial factors. Employment is associated with severity of delete.

Genetic correlates of olanzapine-induced weight gain in schizophrenia subjects from north India: role of metabolic pathway genes

Aim: Olanzapine is an efficacious drug often used as a first-line medication in the treatment for schizophrenia. However, weight gain is a notable adverse drug reaction of this medication in a proportion of patients and a major cause of noncompliance. Several hypotheses, including a contribution from hormonal, physiological and environmental factors, have been postulated. In this study, we aimed to analyze a possible association of genetic polymorphisms at four important candidate genes involved in appetite regulation and antipsychotic-induced metabolic syndrome with olanzapine-induced weight gain. Materials & methods: A total of 154 schizophrenia subjects were recruited in a systematic, 6-week, open-label trial of olanzapine. We investigated the contribution of 14 polymorphisms from four genes, namely, leptin, lipoprotein lipase, tri-acyl-glycerol lipase and citrate lyase using a binary logistic regression analysis towards olanzapine-induced weight gain. Results: rs 4731426 C/G SNP, a variant in the leptin gene, was moderately associated with median weight gain (Δ weightm; [p = 0.05; OR: 2.2; 95% CI: 0.99–4.90]) and significantly associated with extreme weight gain (Δ weighte [p = 0.019; OR: 11.43; 95% CI: 1.49–87.55]) when average drug dose was included in a regression model. Using in silico analysis, we found that this associated intronic SNP in the leptin gene alters the binding of zinc finger 5, a transcription factor. Conclusion: The leptin gene may be a promising candidate for olanzapine-induced weight gain. As the associations are modest, replicate studies are warranted. This approach may facilitate rationalized drug regimens.

Correlates of hallucinations in schizophrenia: A cross-cultural evaluation

INTRODUCTION

Demographic, clinical and familial factors may plausibly influence the manifestation of hallucinations. It is unclear if the pattern of the effects is similar in different environmental/cultural settings.

AIMS

To evaluate factors associated with hallucination from a demographic, clinical and familial perspective in two distinct cultural settings.

METHODS

Patients with a clinical diagnosis of schizophrenia (SZ) or schizoaffective disorder (SZA) were diagnosed systematically using DSM IV criteria. Two independent samples were recruited in India and USA using identical inclusion/exclusion criteria and assessment procedures (n=1287 patients total; 807 Indian and 480 US participants). The association of key demographic and clinical factors with hallucinations of different modalities was examined. To evaluate the impact of familial factors, we separately analyzed correlations among affected sibling pairs (ASPs, n=136, Indian; n=77, US).

RESULTS

The prevalence of different modalities of hallucinations differed in the Indian and US samples, though the rank order of frequency was similar. The pattern of associations between selected variables and the risk of hallucinations was different across cultures, except for some correlations with indices of severity. No significant concordance was observed among the ASPs after correcting for multiple comparisons.

CONCLUSIONS

The factors associated with hallucinations vary across environments. Our results are consistent with a multi-factorial etiology of psychopathology, but re-direct attention to endophenotypic features in the causal chain that precede the symptoms themselves.

Novel, replicated associations between dopamine D3 receptor gene polymorphisms and schizophrenia in two independent samples

BACKGROUND

Meta-analyses have suggested an association between schizophrenia (SZ) and a coding polymorphism (rs6280/Ser9Gly) at the dopamine D3 receptor gene (DRD3), but results have been inconsistent. Because most studies have evaluated only rs6280, the inconsistencies might reflect associations with other variants.

METHODS

We analyzed polymorphisms spanning 109kb in two independent samples (United States: 13 single nucleotide polymorphisms (SNPs), 331 cases, 151 trios, 274 control subjects; India: 11 SNPs, 141 trios).

RESULTS

In the U.S. samples, significant associations were detected with eight SNPs, including rs6280 (p = .001, odds ratio: 1.5). Consistent associations in the case-control and family-based analyses were detected with a common haplotype spanning intron 1 to the 3' region of the gene (rs324029-rs7625282-rs324030-rs2134655-rs10934254; case-control, p = .002; transmission disequilibrium test [TDT], p = .0009; global p-values = .002 and .007, respectively). In the Indian sample, one SNP was associated (rs10934254, p = .03). Moreover, over-transmission of the same common haplotype as the U.S. sample was observed in this cohort (TDT, p = .005; global test, p = .009). Ser9Gly (rs6280) was associated with SZ against this haplotype background but not other haplotypes.

CONCLUSIONS

These data suggest previous inconsistencies might have resulted from associations with other DRD3 variants. A liability locus might be in linkage disequilibrium (LD) with or carried against, an associated haplotype 3' to rs6280. Comprehensive SNP evaluation in larger samples is needed.

Differing correlates for suicide attempts among patients with schizophrenia or schizoaffective disorder in India and USA

BACKGROUND

Suicide is one of the most common causes of death among persons with schizophrenia. Differing risk factors have been identified in published studies. The differences may have arisen because a uniform set of variables was not analyzed. Alternatively, the nature and effect of risk factors may vary in different settings. To test these possibilities, we investigated the same set of variables in two independent cross-national samples ascertained using identical protocols.

METHODS

Patients with schizophrenia or schizoaffective disorder (DSM IV criteria) were recruited in India (n=460) and the USA (n=424).

RESULTS

Consistent with earlier publications, a diagnosis of schizoaffective disorder, history of depression, pattern of symptoms and educational status were significantly associated with suicide attempts in the US sample. None of these variables were significantly associated in the Indian sample.

CONCLUSIONS

The impact of known risk factors for suicide attempts among patients with schizophrenia differs across ethnic groups.

An estimate of the monthly cost of two major mental disorders in an Indian metropolis

BACKGROUND

THE COMPONENTS OF HIGH COST OF TREATING A CHRONIC PSYCHIATRIC ILLNESS ARE: long-term continuous treatment consisting of consultation and medication costs, traveling to the treatment centre and taking time off from work for both patient and caregiver. Apart from direct treatment costs, expenditure of time in care-giving results in indirect costs. All these costs are borne by families as the sufferer may be unable to work.

AIM

To estimate the cost of treatment of chronically ill patients at home, in terms of the above parameters.

METHODS

The sample consisted of 117 subjects of either sex in the age range of 18 to 60 years, ill for at least one year, diagnosed as schizophrenia (n=95) or bipolar disorder (n=22, a comparison group) who agreed to participate in the study along with at least one caregiver. The tools used were the Diagnostic Interview of Genetic Studies and Economic Burden Questionnaire administered to both the subject and the caregiver.

RESULTS AND CONCLUSIONS

The costs of treatment were found to be high but with wide variations in the range. Costs for bipolar disorder were somewhat higher than those for schizophrenia at least for the period of study. Demographic differences between subjects and caregivers were present.

Genetic susceptibility to tardive dyskinesia among schizophrenia subjects: IV. Role of dopaminergic pathway gene polymorphisms

OBJECTIVE

Tardive dyskinesia (TD) is an antipsychotic induced side effect observed in 20-30% of schizophrenia subjects on long-term typical antipsychotic treatment. We tested the possible association of 24 polymorphisms from six dopaminergic genes: namely, dopamine receptors D1, D2, D3, D4; the dopamine transporter (DAT); and the catalyzing enzyme catechol-O-methyltransferase (COMT), with TD.

METHODS

Multiple SNP/VNTR markers from candidate genes were analyzed using suitable approaches and allelic, genotypic and haplotypic associations were tested.

RESULTS

120 bp duplication marker, 1.2 kb upstream from initiation codon of DRD4 gene showed a significant genotypic association [chi2 = 9.29, P = 0.009; OR (95% CI) = 0.52 (0.31-0.86) for genotype 120 dup/120 dup]. In the COMT gene, a significant allelic [chi2 = 13.87, P = 0.0002] as well as genotypic association [chi2 = 16.08, P = 0.0003; OR (95% CI) = 0.24 (0.11-0.55) for genotype GG] was observed with the 408 C>G (exon 4) single nucleotide polymorphism and a significant genotypic association [chi2 = 6.32, P = 0.04; OR (95% CI) = 0.50 (0.33-0.92) for genotype GG] was observed with 472 G > A (exon 4, Val 158 Met) SNP. 120 bp dup-T-repeat 3 in DRD4 and G-C-A-insC in COMT genes were observed to be TD associated haplotypes.

CONCLUSIONS

Our study presents a detailed analysis of the possible role of dopaminergic genes in the genesis of TD. DRD4 and COMT genes were observed to be the most important candidates in North Indian schizophrenia subjects. These suggestive associations need to be investigated in replicate studies.

Genetic susceptibility to Tardive Dyskinesia in chronic schizophrenia subjects: I. Association of CYP1A2 gene polymorphism

Understanding the pharmacogenetic basis of developing iatrogenic disorders such as Tardive Dyskinesia (TD) has significant clinical implications. CYP1A2, an inducible gene of the cytochrome P450 family of genes, has been suggested to contribute to the metabolism of typical antipsychotics in subjects with schizophrenia on long-term treatment, and has been considered as a potential candidate gene for development of TD. In this study, we have investigated the significance of CYP1A2 gene polymorphisms in TD susceptibility among chronic schizophrenia sufferers (n=335) from north India. TD was diagnosed in approximately 29% (96/335) of these subjects. Of the 96 TD positives, 28 had been treated with typical antipsychotics alone, 23 with atypical antipsychotics alone and 45 patients had received both classes of drugs during the course of their illness. Out of the six SNPs tested, CYP1A2(*)2, (*)4, (*)5, (*)6 were found to be monomorphic in our population. CYP1A2(*)1C and CYP1A2(*)1F were polymorphic and were analyzed in the study sample. Since these two allelic variants lead to lesser inducibility among smokers, the smoking status of TD patients was also considered for all subsequent analysis. We observed increased severity of TD among TD-Y smokers, who were carriers of CYP1A2(*)1C (G>A) variant allele and had received only typical antipsychotic drugs (F(1,8)=9.203, P=0.016). No significant association of CYP1A2(*)1F with TD was observed irrespective of the class of drug they received or their smoking status. However, we found a significant association of CYP1A2(*)1F with schizophrenia (chi(2)=6.572, df=2, P=0.037).

Korean version of the diagnostic interview for genetic studies: Validity and reliability

The Diagnostic Interview for Genetic Studies (DIGS), developed in 1994 by the National Institute of Mental Health (NIMH), was translated into Korean and tested for reliability and diagnostic validity. Concurrent validity was tested using the Structured Clinical Interview for DSM-IV (SCID) and clinical diagnoses in 53 patients, most of whom had either schizophrenia or bipolar disorder. Inter-rater reliability was tested in 24 patients. Test-retest reliability was also tested in 17 patients. Overall and specific diagnostic validity for the Korean version of DIGS (DIGS-K) was excellent for most diagnoses. Inter-rater and test-retest reliability for overall and specific diagnoses also ranged from fair to excellent. For schizoaffective disorder, the test-retest reliability of DIGS-K was in a fair range, although the level was lower than that of other diagnoses. However, its diagnostic validity and inter-rater reliability was below fair range. In conclusion, DIGS-K appears to be a reliable interview for major psychiatric disorders.

Evaluation of familial influences on the course and severity of schizophrenia among US and Indian cases

BACKGROUND

Prior studies suggest familial (possibly genetic) influences on the course of schizophrenia.

AIMS

The aim of this study was to compare familial influences on the course and severity of schizophrenia in two independent samples.

METHOD

Thirteen selected measures were compared among affected sibling pairs (ASPs) from Pittsburgh, USA and New Delhi, India (48 US pairs, 53 Indian pairs). For each ASP proband, an unrelated patient was selected randomly from a suitable pool of cases ascertained in the same study (Sibpair proband-comparison case or S-C pairs). Correlations between these pairs were compared.

RESULTS

The correlations varied by item and by site. Significant correlations for longitudinal course and pattern of severity were noted among the ASPs from USA, but did not remain significant following corrections for multiple comparisons. Comparisons between the correlations for ASPs and the S-C pairs, used to estimate familial effects, yielded trends for the ASP correlations to be numerically larger than the S-C correlations in both samples. Separate cross-site comparisons revealed several significant differences with regard to several demographic and clinical variables. The possible impact of the cross-site variations on the observed ASP correlations is discussed.

CONCLUSIONS

Though familial factors did not appear to have a significant impact on course/severity using this novel design, the suggestive trends need to be examined in larger samples.

Molecular genetics of schizophrenia: past, present and future

Schizophrenia is a severe neuropsychiatric disorder with a polygenic mode of inheritance which is also governed by non-genetic factors. Candidate genes identified on the basis of biochemical and pharmacological evidence are being tested for linkage and association studies. Neurotransmitters, especially dopamine and serotonin have been widely implicated in its etiology. Genome scan of all human chromosomes with closely spaced polymorphic markers is being used for linkage studies. The completion and availability of the first draft of Human Genome Sequence has provided a treasure-trove that can be utilized to gain insight into the so far inaccessible regions of the human genome. Significant technological advances for identification of single nucleo-tide polymorphisms (SNPs) and use of microarrays have further strengthened research methodologies for genetic analysis of complex traits. In this review, we summarize the evolution of schizophrenia genetics from the past to the present, current trends and future direction of research.

Diagnostic interview for genetic studies (DIGS): inter-rater and test-retest reliability of alcohol and drug diagnoses

The semi-structured diagnostic interview for genetic studies (DIGS) was developed to assess major mood and psychotic disorders and their spectrum manifestations in genetic studies. Our research group developed a French version of the DIGS and tested its inter-rater and test-retest reliability in psychiatric patients. In this article, we present estimates of the reliability of substance use and antisocial personality disorders. High kappa coefficients for inter-rater reliability were found for drug and alcohol as well as antisocial personality diagnoses and slightly lower kappas for test-retest reliability. Combined with evidence of the reliability of major mood and psychotic disorders, these findings support the suitability of the DIGS for studies of familial aggregation and comorbidity of psychiatric disorders including substance use and antisocial personality disorders.

Association studies of cytosolic phospholipase A2 polymorphisms and schizophrenia among two independent family-based samples

An association between the cytosolic phospholipase A2 locus (cPLA2) and schizophrenia has been reported using two polymorphic DNA markers. In an attempt to replicate these results, two independent family-based samples were ascertained from the United States and India (86 and 159 families, respectively). No significant associations were detected in either sample.

Association study of schizophrenia among Indian families

A putative association of schizophrenia with a Msc I restriction fragment length polymorphism at the dopamine D3 receptor gene locus (DRD3) was tested among Indian families, using haplotype relative risk analysis and the transmission disequilibrium test (n=66 families and 58 sets of transmissions, respectively). A significant association either with homozygosity or with allele 1 at the biallelic polymporphism could not be detected.