Neural mechanisms underlying stress resilience in Ahi1 knockout mice: relevance to neuropsychiatric disorders

The Abelson helper integration site 1 (AHI1) gene has a pivotal role in brain development. Studies by our group and others have demonstrated association of AHI1 with schizophrenia and autism. To elucidate the mechanism whereby alteration in AHI1 expression may be implicated in the pathogenesis of neuropsychiatric disorders, we studied Ahi1 heterozygous knockout (Ahi1(+/-)) mice. Although their performance was not different from wild-type mice on tests that model classical schizophrenia-related endophenotypes, Ahi1(+/-) mice displayed an anxiolytic-like phenotype across different converging modalities. Using behavioral paradigms that involve exposure to environmental and social stress, significantly decreased anxiety was evident in the open field, elevated plus maze and dark-light box, as well as during social interaction in pairs. Assessment of core temperature and corticosterone secretion revealed a significantly blunted response of the autonomic nervous system and the hypothalamic-pituitary-adrenal axis in Ahi1(+/-) mice exposed to environmental and visceral stress. However, response to centrally acting anxiogenic compounds was intact. On resting-state functional MRI, connectivity of the amygdala with other brain regions involved in processing of anxiogenic stimuli and inhibitory avoidance learning, such as the lateral entorhinal cortex, ventral hippocampus and ventral tegmental area, was significantly reduced in the mutant mice. Taken together, our data link Ahi1 under-expression with a defect in the process of threat detection. Alternatively, the results could be interpreted as representing an anxiety-related endophenotype, possibly granting the Ahi1(+/-) mouse relative resilience to various types of stress. The current knockout model highlights the contribution of translational approaches to understanding the genetic basis of emotional regulation and its associated neurocircuitry, with possible relevance to neuropsychiatric disorders.

Effect of triiodothyronine on antidepressant screening tests in mice and on presynaptic 5-HT1A receptors: mediation by thyroid hormone α receptors

Although triiodothyronine (T3) is widely used clinically, preclinical support for its antidepressant-like effects is limited, and the mechanisms are unknown. We evaluated 1) the antidepressant-like effects of T3 in the novelty suppressed feeding test (NSFT), tail suspension test (TST), and forced swim test (FST), 2) the role of presynaptic 5-HT(1A) receptors in the antidepressant-like mechanism of T3 by the hypothermic response to the 5-HT(1A) receptor agonist, 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT), 3) the thyroid hormone receptor type mediating the antidepressant-like effects by concurrent administration of the specific thyroid hormone α receptor (TRα) antagonist, dronedarone, and 4) the presence of these effects in both genders. Male and female BALB/c mice were administered 1) T3 (20, 50, 200, or 500 μg/kg per day) or vehicle or 2) T3 (50 μg/kg per day), dronedarone (100 μM/day), or the combination intraperitoneally for 21 days and then underwent a behavioral test battery. The NSFT showed a shortened latency to feed in males at the two lower T3 doses. The TST and FST showed decreased immobility in male mice at T3 doses >20 μg/kg per day and in females at all T3 doses. Concurrent dronedarone prevented T3 effects in males on the NSFT and in the TST and FST in both genders. Attenuation of 8-OH-DPAT-induced hypothermia was observed in males only and may be reduced by concurrent dronedarone. These findings support an antidepressant-like effect of T3. Attenuation of 8-OH-DPAT-induced hypothermia in males only suggests the need to evaluate a possible gender disparity in the role of presynaptic 5-HT(1A) receptors in T3 antidepressant mechanisms. Blockade by dronedarone of the antidepressant-like effects of T3 suggests that these effects are TRα receptor-mediated.

Evidence for an interaction of schizophrenia susceptibility loci on chromosome 6q23.3 and 10q24.33-q26.13 in Arab Israeli families

A genome scan for schizophrenia related loci in Arab Israeli families by Lerer et al. [Lerer et al. (2003); Mol Psychiatry 8:488-498] detected significant evidence for linkage at chromosome 6q23. Subsequent fine mapping [Levi et al. (2005); Eur J Hum Genet 13:763-771], association [Amann-Zalcenstein et al. (2006); Eur J Hum Genet 14:1111-1119] and replication studies [Ingason et al. (2007); Eur J Hum Genet 15:988-991] identified AHI1 as a putative susceptibility gene. The same genome scan revealed suggestive evidence for a schizophrenia susceptibility locus in the 10q23-26 region. Genes at these two loci may act independently in the pathogenesis of the disease in our homogeneous sample of Arab Israeli families or may interact with each other and with other factors in a common biological pathway. The purpose of our current study was to test the hypothesis of genetic interaction between these two loci and to identify the type of interaction between them. The initial stage of our study focused on the 10q23-q26 region which has not been explored further in our sample. The second stage of the study included a test for possible genetic interaction between the 6q23.3 locus and the refined 10q24.33-q26.13 locus. A final candidate region of 19.9 Mb between markers D10S222 (105.3 Mb) and D10S587 (125.2 Mb) was found on chromosome 10 by non-parametric and parametric linkage analyses. These linkage findings are consistent with previous reports in the same chromosomal region. Two-locus multipoint linkage analysis under three complex disease inheritance models (heterogeneity, multiplicative, and additive models) yielded a best maximum LOD score of 7.45 under the multiplicative model suggesting overlapping function of the 6q23.3 and 10q24.33-q26.13 loci.

Allelic variation in ApoC3, ApoA5 and LPL genes and first and second generation antipsychotic effects on serum lipids in patients with schizophrenia

Schizophrenic patients who are treated with antipsychotics, especially second generation antipsychotics, such as clozapine and olanzapine, manifest an increase in cholesterol and triglycerides as well as other changes associated with diabetes or the metabolic syndrome. Previous studies have shown that polymorphisms in several genes that regulate lipid metabolism can influence the levels of these lipids and response to drug treatment. We have investigated in an exploratory study whether polymorphisms in the apolipoprotein C-III (ApoC3), apolipoprotein A-V gene (ApoA5) and lipoprotein lipase genes influence differential lipid response to treatment with three second generation antipsychotics-olanzapine, clozapine and risperidone-or treatment with a first generation antipsychotic. A total of 189 patients with schizophrenia or schizoaffective disorder who were being treated with a single antipsychotic were studied in a cross-sectional study design in which fasting serum cholesterol and triglycerides and selected single-nucleotide polymorphosms (SNPs) in the three lipid metabolism genes were assessed. The treatment with antipsychotic monotherapy makes drug haplotype ascertainment less complex. Our analyses showed several nominally significant drug x gene and drug x haplotype interactions. The rarer C allele or the ApoA5_1131 (T/C) SNP was associated with higher cholesterol levels in patients treated with first generation antipsychotics and lower cholesterol levels in patients treated with olanzapine or clozapine. The rarer C allele of the ApoA5_SW19 (G/C) SNP was associated with higher cholesterol in risperidone-treated patients. An ApoA5 CG haplotype was associated with decreased cholesterol in olanzapine- or clozapine-treated patients and higher cholesterol in patients treated with first generation antipsychotics. The presence of the rarer T allele of the ApoC3_1100 (C/T) SNP or the presence of the ApoC3 TG haplotype was associated with decreased triglyceride levels in patients treated with olanzapine or clozapine and a nonsignificant trend for increased triglycerides in patients treated with first generation antipsychotics. The presence of the ApoC3 CC haplotype was associated with increased triglycerides in patients treated with olanzapine or clozapine. The overall magnitude of the effects was not large. These results provide a potential initial step toward a pharmacogenetic approach to selection of antipsychotic treatment which may help minimize the side effect of increases in serum lipids.

Why do young women smoke? V. Role of direct and interactive effects of nicotinic cholinergic receptor gene variation on neurocognitive function

Previous work suggests that young women who smoke cigarettes regularly, or did so in the past, manifest a neurocognitive profile that is characterized by small but significant impairments of response inhibition and attention. The present study sought to determine whether variation in nicotinic cholinergic receptor (nAchR) genes impacts upon cognitive function in these domains by overall or differential effects on the performance of current, former and non-smokers. The study sample consisted of 100 female college students, current or past smokers, and 144 who had never smoked. All performed a computerized neurocognitive test battery and were genotyped for 39 single nucleotide polymorphisms in 11 nAchR genes. The results, derived from linear or logistic regression, show significant direct and interactive relationships between single nucleotide polymorphisms and haplotypes in several nAchR genes and performance on the Matching Familiar Figures Test (MFFT) Stroop test, Continuous Performance Task (CPT) and Tower of London (TOL) test. Response inhibition (MFFT, Stroop, CPT Loading Phase, TOL) was associated with variants in CHRNA2, CHRNA4, CHRNA5, CHRNA7, CHRNA9, CHRNA10, CHRNB2 and CHRNB3. Selective attention (Stroop) was associated with CHRNA4, CHRNA5, CHRNA9 and CHRNB2. Sustained attention (CPT Boring Phase) was associated with CHRNA4, CHRNA5, CHRNA7, CHRNA10 and CHRNB3. Up to 37% of the variance among the smokers and up to 47% of the variance among the non-smokers on the test measures was explained. Differences between smokers and non-smokers in neurocognitive function, putatively implicated in susceptibility to nicotine dependence, may be modulated by variants in nAchR genes, with potential implications for prevention and treatment.

Evaluation of association of SNPs in the TNF alpha gene region with schizophrenia

The association of the tumor necrosis factor alpha (TNFalpha) -G308A promoter polymorphism with schizophrenia has complemented clinical findings of increased levels of the TNFalpha cytokine in schizophrenic patients, with some support for a functional consequence of the variant. Our previous studies of genetic causes in schizophrenia supported findings of linkage to the major histocompatibility complex (MHC) region where the TNFalpha gene is located as well as association with the -G308A promoter polymorphism. While the common G-allele shows association in our sample, association with the A-allele has been reported by other groups. This suggests linkage disequilibrium (LD) rather than direct involvement in the disorder. In order to define LD of DNA variants with the disorder in this area, we analyzed 36 SNPs in a 165-kb region around this polymorphism. We detected nominally significant associations (P < 0.05) of three markers (including the -G308A promoter polymorphism) and multiple haplotypes with schizophrenia in our sample of 204 families (79 sib-pairs and 125 trios). The association is largely restricted to a 30 kb high LD region/block and should assist in the identification of a schizophrenia susceptibility gene within the block or elsewhere in the MHC.

Genetic susceptibility to Tardive Dyskinesia in chronic schizophrenia subjects: V. Association of CYP1A2 1545 C>T polymorphism

Tardive dyskinesia (TD) is an iatrogenic disorder observed in approximately 20-30% of schizophrenia patients on long-term treatment with typical antipsychotic drugs. CYP1A2 is involved in the metabolism of atypical antipsychotic drugs such as clozapine and olanzapine. It is not directly involved in the metabolism of typical antipsychotic drugs, but gains importance when the schizophrenia patients are under long-term chronic treatment, acting as a low-affinity high-capacity metabolizing enzyme. In this study, we have completely sequenced the coding region to ascertain the presence of common coding polymorphisms and their role if any in susceptibility to TD and schizophrenia. Four previously reported polymorphisms, CYP1A2*1F (intron A), rs2472304 & rs3743484 (intron D) and rs2470890 (CYP1A2 1545 C>T) in exon 7 were identified. We further investigated whether the CYP1A2 1545 C>T polymorphism has any role to play in susceptibility to TD and in schizophrenia per se. Association of this single nucleotide polymorphism with TD (P=0.03) and schizophrenia (P=0.04) was observed, but was rendered insignificant after corrections for multiple comparisons.

Evidence for association of DNA sequence variants in the phosphatidylinositol-4-phosphate 5-kinase IIalpha gene (PIP5K2A) with schizophrenia

Linkage studies in schizophrenia have identified a candidate region on chromosome 10p14-11 as reported for several independent samples. We investigated association of DNA sequence variants in a plausible candidate gene located in this region, the gene for phosphatidylinositol-4-phosphate 5-kinase IIalpha (PIP5K2A), in a sample of 65 sib-pair families for which linkage had been reported. Evidence for association was obtained for 15 polymorphisms spanning 73.6 kb in the genomic region of the gene between intron 4 and the 3' untranslated region, a region with high degree of linkage disequilibrium. Single nucleotide polymorphism (SNP) rs10828317 located in exon 7 and causing a non-synonymous amino-acid exchange (asparagine/serine) produced a P-value of 0.001 (experiment-wide significance level 0.00275) for over-transmission of the major allele coding for serine, analysed by transmission disequilibrium test using FAMHAP. Association of this SNP with schizophrenia has been also described in a sample of 273 Dutch schizophrenic patients and 580 controls (P=0.0004). PIP5K2A is involved in the biosynthesis of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), one of the key metabolic crossroads in phosphoinositide signalling. PI(4,5)P2 plays a role in membrane transduction of neurotransmitter signals as well as in intracellular signalling, pathways that may be impaired in schizophrenia.

Why do young women smoke? II. Role of traumatic life experience, psychological characteristics and serotonergic genes

Cigarette smoking is a complex behavioral phenotype to which environmental, psychological and genetic factors contribute. The purpose of this study was to investigate these multifactorial effects with a specific focus on young women and on genes that encode serotonin (5-HT) receptors and the 5-HT transporter. A case-control sample of female Israeli college students provided comprehensive background data and details of cigarette smoking and completed a battery of psychological instruments. They were divided into smoking initiators (SI, n=242) or non-initiators (NI, n=148); SI were further subdivided into high (HND, n=127) and low nicotine-dependent smokers (LND, n=115) on the basis of their scores on the Fagerstrom Tolerance Questionnaire (FTQ). Single-nucleotide polymorphisms (SNPs) in five serotonin receptor genes (HTR1A, HTR1B, HTR2A, HTR2C and HTR6) and the 5-HT transporter-linked polymorphic region (5-HTTLPR) were genotyped. In a logistic regression model for SI (chi2=117.90, P=1.6 x 10(-19), Nagelkerke R2=0.42), novelty seeking (odds ratio (OR)=1.134, P=0.00009) was a significant risk factor. A five SNP CACCC haplotype in HTR6 was a strong protective factor against SI (OR=0.26; P=0.007). The interaction of HTR6-C276T genotype and lifetime traumatic experience contributed strongly to the risk of SI (OR=13.88, P=0.0001). Specifically, subjects homozygous for the HTR6-C276T C allele showed significantly increased risk of SI if they had experienced trauma. Although significant (chi2=42.85, P=1.00 x 10(-7)), the best-fitting model for ND was less predictive than the model for SI (Nagelkerke R2=0.24). HTR1B-G861C GG genotype (OR=2.29, P=0.01) was a significant risk factor for HND. Further studies should consider the interactive contribution of life events and relevant gene variants to cigarette smoking and other complex behavioral traits.

Genome-wide linkage scan in a large bipolar disorder sample from the National Institute of Mental Health genetics initiative suggests putative loci for bipolar disorder, psychosis, suicide, and panic disorder

We conducted a 9-cM genome scan in a large bipolar pedigree sample from the National Institute of Mental Health genetics initiative (1060 individuals from 154 multiplex families). We performed parametric and nonparametric analyses using both standard diagnostic models and comorbid conditions thought to identify phenotypic subtypes: psychosis, suicidal behavior, and panic disorder. Our strongest linkage signals (genome-wide significance) were observed on chromosomes 10q25, 10p12, 16q24, 16p13, and 16p12 using standard diagnostic models, and on 6q25 (suicidal behavior), 7q21 (panic disorder) and 16p12 (psychosis) using phenotypic subtypes. Several other regions were suggestive of linkage, including 1p13 (psychosis), 1p21 (psychosis), 1q44, 2q24 (suicidal behavior), 2p25 (psychosis), 4p16 (psychosis, suicidal behavior), 5p15, 6p25 (psychosis), 8p22 (psychosis), 8q24, 10q21, 10q25 (suicidal behavior), 10p11 (psychosis), 13q32 and 19p13 (psychosis). Over half the implicated regions were identified using phenotypic subtypes. Several regions - 1p, 1q, 6q, 8p, 13q and 16p - have been previously reported to be linked to bipolar disorder. Our results suggest that dissection of the disease phenotype can enrich the harvest of linkage signals and expedite the search for susceptibility genes. This is the first large-scale linkage scan of bipolar disorder to analyze simultaneously bipolar disorder, psychosis, suicidal behavior, and panic disorder.

Why do young women smoke? I. Direct and interactive effects of environment, psychological characteristics and nicotinic cholinergic receptor genes

Despite the health hazards, cigarette smoking is disproportionately frequent among young women. A significant contribution of genetic factors to smoking phenotypes is well established. Efforts to identify susceptibility genes do not generally take into account possible interaction with environment, life experience and psychological characteristics. We recruited 501 female Israeli students aged 20-30 years, obtained comprehensive background data and details of cigarette smoking and administered a battery of psychological instruments. Smoking initiators (n=242) were divided into subgroups with high (n=127) and low (n=115) levels of nicotine dependence based on their scores on the Fagerstrom Tolerance Questionnaire and genotyped with noninitiators (n=142) for single nucleotide polymorphisms (SNPs) in 11 nicotinic cholinergic receptor genes. We found nominally significant (P<0.05) allelic and genotypic association with smoking initiation of SNP rs2072660 and multilocus haplotypes (P<0.007-0.05) in CHRNB2 and nominal (P<0.05) allelic or genotypic association of SNPs in CHRNA7 (rs1909884), CHRNA9 (rs4861065) and CHRNB3 (rs9298629) with nicotine dependence. Employing logistic regression and controlling for known risk factors, the best-fitting model for smoking initiation encompassed a 5 SNP haplotype in CHRNB2, neuroticism and novelty seeking (P=5.9 x 10(-14), Nagelkerke r(2)=0.30). For severity of nicotine dependence, two SNPs in CHRNA7 (rs1909884 and rs883473), one SNP in CHRNA5 (rs680244) and the interaction of a SNP in CHRNA7 (rs2337980) with neuroticism, were included in the model (P=2.24 x 10(-7), Nagelkerke r(2)=0.40). These findings indicate that background factors, psychological characteristics and genetic variation in nicotinic cholinergic receptors contribute independently or interactively to smoking initiation and to severity of nicotine dependence in young women.

Excitement and confusion on chromosome 6q: the challenges of neuropsychiatric genetics in microcosm

The search for genes that are implicated in the pathogenesis of schizophrenia (SCZ), bipolar disorder (BPD) and other complex neuropsychiatric phenotypes has yielded a plethora of positive findings, but has also engendered a substantial degree of confusion. Exciting findings include positive linkage results in a number of chromosomal regions and the identification of several genes that have been associated with SCZ and to a lesser extent with BPD. Confusing aspects include the difference between studies in localization of linkage peaks in the same chromosomal regions, raising the possibility that these regions may harbor more than one gene, the fact that positive linkage findings as well as associated genes appear in several cases to be shared by more than one disorder, and the failure to identify thus far the precise pathogenic variants in associated genes. Recent findings of linkage and association studies on chromosome 6q illustrate the current status of neuropsychiatric genetics in intriguing microcosm. Positive findings from linkage and association studies are reviewed in order to identify approaches that may help to settle apparent contradictions and allow an interpretation of the results that may prove useful in application to findings from other chromosomal regions. Not only SCZ and BPD but also other psychiatric and neurological phenotypes are considered. Taking a topographic approach, we identify five foci of positive findings on chromosome 6q and suggest that each may harbor gene(s) that confer susceptibility to SCZ or BPD or may modify their onset or clinical course. We further suggest that in searching for these genes the possibility that they may be implicated in more than one disorder should be taken into account. We also discuss the potential contribution of rare genetic variants identified in homogeneous, isolated populations to the subsequent identification of common variants in the same gene that contribute to disease susceptibility in outbred populations.

Linkage analysis of psychosis in bipolar pedigrees suggests novel putative loci for bipolar disorder and shared susceptibility with schizophrenia

The low-to-moderate resolution of linkage analysis in complex traits has underscored the need to identify disease phenotypes with presumed genetic homogeneity. Bipolar disorder (BP) accompanied by psychosis (psychotic BP) may be one such phenotype. We previously reported a genome-wide screen in a large bipolar pedigree sample. In this follow-up study, we reclassified the disease phenotype based on the presence or absence of psychotic features and subgrouped pedigrees according to familial load of psychosis. Evidence for significant linkage to psychotic BP (genome-wide P<0.05) was obtained on chromosomes 9q31 (lod=3.55) and 8p21 (lod=3.46). Several other sites were supportive of linkage, including 5q33 (lod=1.78), 6q21 (lod=1.81), 8p12 (lod=2.06), 8q24 (lod=2.01), 13q32 (lod=1.96), 15q26 (lod=1.96), 17p12 (lod=2.42), 18q21 (lod=2.4), and 20q13 (lod=1.98). For most loci, the highest lod scores, including those with genome-wide significance (at 9q31 and 8p21), occurred in the subgroup of families with the largest concentration of psychotic individuals (> or =3 in a family). Interestingly, all regions but six--5q33, 6q21, 8p21, 8q24, 13q32 and 18q21--appear to be novel; namely, they did not show notable linkage to BP in other genome scans, which did not employ psychosis for disease classification. Also of interest is possible overlap with schizophrenia, another major psychotic disorder: seven of the regions presumed linked in this study--5q, 6q, 8p, 13q, 15q, 17p, and 18q--are also implicated in schizophrenia, as are 2p13 and 10q26, which showed more modest support for linkage. Our results suggest that BP in conjunction with psychosis is a potentially useful phenotype that may: (1) expedite the detection of susceptibility loci for BP and (2) cast light on the genetic relationship between BP and schizophrenia.

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).

Maternal transmission disequilibrium of the glutamate receptor GRIK2 in schizophrenia

Schizophrenia is characterized by thought disorders, hallucinations and delusions. Genetic studies have shown a high linkage at chromosome 6q16-21. Among the genes located in this region is the glutamate receptor ionotropic kainate 2 gene (GRIK2 or GLUR6), a functional candidate for susceptibility to schizophrenia. In this study, transmission of GRIK2 was evaluated in 356 schizophrenic patients from three different clinical centers. Whereas paternal transmission shows equilibrium, we observed maternal transmission disequilibrium of GRIK2 in the largest population (p=0.03), which was still significant when all populations were added (p=0.05). These results are similar to the maternal GRIK2 transmission disequilibrium previously reported for autism, and support the presence of a susceptibility gene for schizophrenia at 6q16.

Association of dopaminergic and serotonergic genes with tardive dyskinesia in patients with chronic schizophrenia

Tardive dyskinesia (TD) is a long-term adverse effect of antipsychotic drugs that are dopamine D2 receptor blockers. Serotonin receptor antagonism has been proposed as a common mechanism contributing to the low extrapyramidal side effect profile of atypical antipsychotic drugs. We evaluated candidate dopamine and serotonin genes for association with drug-induced TD. We examined three polymorphisms in the dopamine D2 receptor gene (DRD2), two sites in the 3' region of the dopamine transporter (DAT) gene, two sites in the promoter and coding region of the dopamine D4 (DRD4) receptor gene, as well as polymorphic sites in the serotonin 6 receptor gene, the serotonin transporter gene and the tryptophan hydroxylase gene, for association with TD susceptibility. Schizophrenic patients with (n=59) and without TD (n=63), matched for antipsychotic drug exposure and other relevant variables, were studied. No significant associations were found. Within the limitations imposed by the size of the clinical sample, these findings suggest that the above polymorphic loci do not contribute significantly to risk for TD. Further examination of loci that yielded positive results at a trend level and investigation of other candidate genetic loci coding for antipsychotic drug targets is warranted.

Social adjustment and self-esteem of bipolar patients: a multicentric study

The aim of the present study was to investigate impairment in social adjustment and self-esteem of bipolar patients (n=144) in remission for at least 3 months. Patients were recruited among four different centres: Sofia, Athens, Jerusalem and Milan, and were individually matched to control subjects in relation to sex, age and geographical origin. Subjects completed the Rosenberg self-esteem scale (SES) and the self-report version of the social adjustment scale (SAS). Bipolar patients reported to experience more difficulties in social adjustment than controls, specifically for leisure and work activities. Further, our results show that bipolar patients have significantly lower self-esteem compared to controls, even after remission.

Illness recognition and disruptiveness in psychotic illness

A case control investigation was performed to examine the relatively high rate of unrecognized psychotic illness within an extended family with a high-density of psychotic illness and identify factors related to nonrecognition. The study was conducted within the catchment area of a Regional Mental Health Center in central Israel. Subjects were recruited using clinic records indicating multiple family members with mental illness. Additional subjects were recruited in the homes of the subjects through family members. A total of 247 subjects were recruited, 111 of whom were determined to suffer from a psychotic disorder based on criteria in standard use. Sixty-six subjects were members of a single extended family (clan) and 181 subjects were members of nonrelated families residing in the same geographic area. While the rate of unrecognized psychotic illness was insignificant among the members of the families not related to the clan, among clan members the rate of unrecognized psychotic illness was 45%. Among this clan, recognition of psychotic illness appeared to be directly related to disruptive behavior. Additionally, it was found that, overall, subjects were more likely to recognized by the mental health system if they had fewer ill family members and more education. We conclude that although nonrecognition of mental illness does not appear to be a problem among the families in the area who are not related to the particular clan, within the clan a particular subculture appears to have developed in which perceived need for psychiatric services is related to disruptive behavior. A high density of psychotic illness within a family and less education may create a family environment that becomes tolerant of psychotic symptoms that are not disruptive to others, resulting in nonrecognition of nondisruptive illness by the mental health system.

Association study of cannabinoid receptor gene (CNR1) alleles and anorexia nervosa: differences between restricting and binging/purging subtypes

Anorexia nervosa (AN) is a severe and disabling psychiatric disorder, characterized by profound weight loss and body image disturbance. Family and twin studies indicate a significant genetic contribution to this disorder although no genetic mutation has yet been identified. The endocannabinoid system has recently been implicated in many physiological functions including appetite regulation. We, therefore, undertook a family based study to test the hypothesis whether a polymorphism of the CNR1 gene, which encodes human CB1 receptor, a subclass of the central cannabinoid receptor, contributes to the susceptibility to AN. Fifty two families (parents with one or two affected siblings) were genotyped for the (AAT) trinucleotide repeat of CNR1 gene. Using the haplotype relative risk (HRR) method, the distribution of alleles transmitted to the patients was not found to be significantly different from the non-transmitted parental alleles. However, upon dividing the samples to restricting and binging/purging subtypes of AN, the extended transmission disequilibrium test (ETDT) revealed that there is preferential transmission of different alleles in each of the subtypes. The 14 repeat allele was preferentially transmitted in the binging/purging AN group (P = 0.05) but not in the restricting AN group, whereas the 13 repeat allele was preferentially transmitted in the restricting AN group (almost significant, P = 0.07) but not in the binging/purging AN group. Our study suggests that restricting AN and binging/purging AN may be associated with different alleles of the CNR1 gene.

Genome scan of Arab Israeli families maps a schizophrenia susceptibility gene to chromosome 6q23 and supports a locus at chromosome 10q24

Schizophrenia is a complex neuropsychiatric disorder to which an as-yet-unknown number of genes contribute, interacting with each other and the environment. Linkage analyses have implicated several chromosomal regions as harboring schizophrenia susceptibility loci although rarely at levels commensurate with proposed thresholds for genome-wide significance. We systematically recruited Arab Israeli families multiply affected with schizophrenia from the catchment area of a Regional Mental Health Center. Clinical diagnoses were established by semistructured interviews and all other available sources of information under narrow, core and broad categories. Using 350 microsatellite markers, spaced at an average of 10.3 cM, we performed an autosomal scan in 155 subjects from 21 families. Linkage analysis employed affects only, multipoint, nonparametric (model-free) and also parametric (dominant and recessive) approaches. We detected significant evidence for a schizophrenia susceptibility gene at chromosome 6q23 with a nonparametric LOD score (NPL) of 4.60 (P=0.000004) under the broad diagnostic category and a parametric LOD score of 3.33 (dominant model). Under the core diagnostic category the NPL was 4.29 (P=0.00001) and the LOD score 4.16 (dominant model). We also detected suggestive evidence for linkage at chromosome 10q24 under the broad diagnostic category (NPL 3.24, P=0.0008; heterogeneity LOD score, dominant model 2.65, alpha=0.82). Additionally, NPL scores >2.0 were observed at chromosome 2q37, 4p15-16, 7p22, 9q21-22 and 14q11.1-11.2. The linkage we detected at chromosome 6q23 fulfills the criteria for genome-wide significance and is located approximately midway between loci suggested by a previous significant report at chromosome 6q25 and findings located more centromerically at 6q21-22.

Evidence for a putative bipolar disorder locus on 2p13-16 and other potential loci on 4q31, 7q34, 8q13, 9q31, 10q21-24, 13q32, 14q21 and 17q11-12

Bipolar disorder (BP) is a severe and common psychiatric disorder characterized by extreme mood swings. Family, twin and adoption studies strongly support a genetic component. The mode of inheritance is complex and likely involves multiple, as yet unidentified genes. To identify susceptibility loci, we conducted a genome-wide scan with 343 microsatellite markers in one of the largest, well-characterized pedigree samples assembled to date (373 individuals in 40 pedigrees). To increase power to detect linkage, scan statistics were used to examine the logarithm of odds (lod) scores based on evidence at adjacent chromosomal loci. This analysis yielded significant evidence of linkage (genome-wide P&<0.05) for markers on 2p13-16. Standard linkage analysis was also supportive of linkage to 2p13-16 (lod=3.20), and identified several other interesting regions: 4q31 (lod=3.16), 7q34 (lod=2.78), 8q13 (lod=2.06), 9q31 (lod=2.07), 10q24 (lod=2.79), 13q32 (lod=2.2), 14q21 (lod=2.36) and 17q11-12 (lod=2.75). In this systematic, large-scale study, we identified novel putative loci for BP (on 2p13-16, 8q13 and 14q21) and found support for previously proposed loci (on 4q31, 7q34, 9q31, 10q21-24, 13q32 and 17q11-12). Two of the regions implicated in our study, 2p13-14 and 13q32, have also been linked to schizophrenia, suggesting that the two disorders may have susceptibility genes in common.

A genome screen for genes predisposing to bipolar affective disorder detects a new susceptibility locus on 8q

Bipolar affective disorder (BPAD), also known as manic depressive illness, is a severe psychiatric disorder characterized by episodes of mania and depression. It has a lifetime prevalence of approximately 1% in all human populations. In order to identify chromosomal regions containing genes that play a role in determining susceptibility to this psychiatric condition, we have conducted a complete genome screen with 382 markers (average marker spacing of 9.3 cM) in a sample of 75 BPAD families which were recruited through an explicit ascertainment scheme. Pedigrees were of German, Israeli and Italian origin, respectively. Parametric and non-parametric linkage analysis was performed. The highest two-point LOD score was obtained on 8q24 (D8S514; LOD score = 3.62), in a region that has not attracted much attention in previous linkage studies of BPAD. The second best finding was seen on 10q25-q26 (D10S217; LOD score = 2.86) and has been reported in independent studies of BPAD. Other regions showing 'suggestive' evidence for linkage localized to 1p33-p36, 2q21-q33, 3p14, 3q26-q27, 6q21-q22, 8p21, 13q11 and 14q12-q13. In addition, we aimed at detecting possible susceptibility loci underlying genomic imprinting by analyzing the autosomal genotype data with the recently developed extension of the GENEHUNTER program, GENEHUNTER-IMPRINTING. Putative paternally imprinted loci were identified in chromosomal regions 2p24-p21 and 2q31-q32. Maternally imprinted susceptibility genes may be located on 14q32 and 16q21-q23.

Variability of 5-HT2C receptor cys23ser polymorphism among European populations and vulnerability to affective disorder

Substantial evidence supports a role for dysfunction of brain serotonergic (5-HT) systems in the pathogenesis of major affective disorder, both unipolar (recurrent major depression) and bipolar.(1) Modification of serotonergic neurotransmission is pivotally implicated in the mechanism of action of antidepressant drugs(2) and also in the action of mood stabilizing agents, particularly lithium carbonate.(3) Accordingly, genes that code for the multiple subtypes of serotonin receptors that have been cloned and are expressed in brain,(4) are strong candidates for a role in the genetic etiology of affective illness. We examined a structural variant of the serotonin 2C (5-HT2C) receptor gene (HTR2C) that gives rise to a cysteine to serine substitution in the N terminal extracellular domain of the receptor protein (cys23ser),(5) in 513 patients with recurrent major depression (MDD-R), 649 patients with bipolar (BP) affective disorder and 901 normal controls. The subjects were drawn from nine European countries participating in the European Collaborative Project on Affective Disorders. There was significant variation in the frequency of the HT2CR ser23 allele among the 10 population groups included in the sample (from 24.6% in Greek control subjects to 9.2% in Scots, chi(2) = 20.9, df 9, P = 0.01). Logistic regression analysis demonstrated that over and above this inter-population variability, there was a significant excess of HT2CR ser23 allele carriers in patients compared to normal controls that was demonstrable for both the MDD (chi(2) = 7.34, df 1, P = 0.006) and BP (chi(2) = 5.45, df 1, P = 0.02) patients. These findings support a possible role for genetically based structural variation in 5-HT2C receptors in the pathogenesis of major affective disorder.

Association analysis of NOTCH4 loci in schizophrenia using family and population-based controls

A genetic association between NOTCH4 and schizophrenia has previously been proposed. Unsing all markers previously shown to be associated, we found no evidence for such in three independent family-based samples (n=519 parent-offspring trios), and a case-control sample derived from the same ethnic background as the original observation. These data strongly suggest that NOTCH4 is not a significant susceptibility allele for schizophrenia.

A possible susceptibility locus for bipolar affective disorder in chromosomal region 10q25--q26

In an attempt to identify susceptibility loci for bipolar affective disorder, we are currently conducting a systematic genome screen with highly polymorphic microsatellite markers at an average marker spacing of 10 cM in a series of 75 families, comprising 66 families from Germany, eight families from Israel, and one family from Italy. The families were ascertained through index cases with bipolar affective disorder. The distribution of diagnoses is as follows: 126 individuals with bipolar I disorder, 40 with bipolar II disorder, 14 with schizoaffective disorder of the bipolar type, 40 individuals with recurrent unipolar depression, 51 with a minor psychiatric diagnosis, and two individuals with a diagnosis of schizophrenia. One hundred and seventy-one individuals are unaffected. Here, we present results from chromosome 10. Linkage analyses using a total of 33 microsatellite markers with parametric and non-parametric methods provided evidence for linkage at chromosomal region 10q25--q26. The highest two-point LOD score (2.86, theta = 0.05) was obtained for D10S217 using a dominant genetic model and a broad definition of affection status. The GENEHUNTER program localized the putative susceptibility locus within a ca 15-cM interval between markers D10S1483 and D10S217 with a maximum NPL(all) score of 3.12 (P = 0.0013). Positive linkage findings that have been reported by two independent studies further support the hypothesis of a susceptibility gene for bipolar affective disorder on 10q25-q26.

Duffy antigen/receptor for chemokines (DARC): genotypes in Ashkenazi and non-Ashkenazi Jews in Israel

Duffy genotypes were studied in Ashkenazi and non-Ashkenazi groups in Israel. The prevalence of the genotypes for the known polymorphic FY*A, FY*B, and FY*B(GATA-) alleles was similar in the two groups. The recently described FY*B(G298A) and FY*B(C265T) alleles were also found to be polymorphic. FY*B(G298A) was significantly more prevalent in the non-Ashkenazi group than in the Ashkenazi group (in 20% and 10% of FY*B, respectively). FY*B(C265T), which markedly diminishes the expression of Fy(b) antigen, was found in 3.5% of FY*B alleles, but only together with FY*B(G298A), consistent with previous suggestions that FY*B(C265T) occurred in the FY*B(G298A) allele. No difference in Duffy genotype distribution was found between schizophrenic and control groups. Duffy antigens are receptors for chemokines and bind Plasmodium vivax. Study of Duffy genotypes in additional populations might help in elucidating the possible functional significance of Duffy allele polymorphism.

A follow-up linkage study supports evidence for a bipolar affective disorder locus on chromosome 21q22

Evidence for linkage between bipolar affective disorder (BP) and 21q22 was first reported by our group in a single large pedigree with a lod score of 3.41 with the PFKL locus. In a subsequent study, with denser marker coverage in 40 multiplex BP pedigrees, we reported supporting evidence with a two-point lod score of 2.76 at the D21S1260 locus, about 6 cM proximal to PFKL. For cost-efficiency, the individuals genotyped in that study comprised a subset of our large pedigree sample. To augment our previous analysis, we now report a follow-up study including a larger sample set with an additional 331 typed individuals from the original 40 families, improved marker coverage, and an additional 16 pedigrees. The analysis of all 56 pedigrees (a total of 862 genotyped individuals vs. the 372 genotyped previously), the largest multigenerational BP pedigree sample reportedly analyzed to date, supports our previous results, with a two-point lod score of 3.56 with D21S1260. The 16 new pedigrees analyzed separately gave a maximum two-point lod score of 1.89 at D21S266, less than 1 cM proximal to D21S1260. Our results are consistent with a putative BP locus on 21q22.

An open trial of plant-source derived phosphatydilserine for treatment of age-related cognitive decline

We assessed whether the efficacy of plant-source derived phosphatydilserine (one of the phospholipids which play an important functional role in membrane-related processes in the brain) for treatment of age related cognitive decline is consistent with previous (placebo controlled) positive findings with bovine derivative of PS (BC-PS). Eighteen healthy elderly volunteers meeting Age Associated Memory Impairment inclusion and exclusion criteria were treated for 12 weeks with plant-source derived phosphatydilserine (PS) (100 mg x 3/day p.o.) and evaluated at base line, after 6 weeks of treatment and at the end of the trial. Fifteen concluded the study. All but two outcome measures elicited a significant drug over time effect. Post-hoc paired t-tests showed that the significant effect was attributable to an improvement from base line to week 6 and that effect was maintained at week 12. These results are encouraging. However, they await double-blind controlled verification in a large sample before suggesting that this may be a viable approach to the treatment of age-related cognitive decline, without exposing the patients to possible hazards involved in the treatment with bovine derivative of PS (BC-PS).

Tryptophan hydroxylase polymorphism and suicidality in unipolar and bipolar affective disorders: a multicenter association study

BACKGROUND

Being the rate-limiting enzyme in the biosynthesis of serotonin, the tryptophan hydroxylase gene (TPH) has been considered a possible candidate gene in bipolar and unipolar affective disorders (BPAD and UPAD). Several studies have investigated the possible role of TPH polymorphisms in affective disorders and suicidal behavior.

METHODS

The TPH A218C polymorphism has been investigated in 927 patients (527 BPAD and 400 UPAD) and their matched healthy control subjects collected within the European Collaborative Project on Affective Disorders.

RESULTS

No difference of genotype distribution or allele distribution was found in BPAD or UPAD. No statistically significant difference was observed for allele frequency and genotypes counts. In a genotype per genotype analysis in UPAD patients with a personal history of suicide attempt, the frequency of the C-C genotype (homozygosity for the short allele) was lower in UPAD patients (24%) than in control subjects (43%) (chi(2) = 4.67, p =.03). There was no difference in allele or genotype frequency between patients presenting violent suicidal behavior (n = 48) and their matched control subjects.

CONCLUSIONS

We failed to detect an association between the A218C polymorphism of the TPH gene and BPAD and UPAD in a large European sample. Homozygosity for the short allele is significantly less frequent in a subgroup of UPAD patients with a history of suicide attempt than in control subjects.

Association between the serotonin 2A receptor gene and tardive dyskinesia in chronic schizophrenia

Tardive dyskinesia (TD) is a long-term adverse effect of antipsychotic drugs that are dopamine D2 receptor blockers.(1) Serotonin receptor antagonism has been proposed as a common mechanism contributing to the low extrapyramidal effects profile of atypical antipsychotic drugs.(2) We examined the association of three polymorphisms in the 5-HT2A receptor gene (HTR2A) with TD susceptibility--T102C(3) and his452tyr(4) in the coding region and A-1438G(5) in the promoter--in matched schizophrenia patients with (n = 59, SCZ-TD-Y) and without TD (n = 62, SCZ-TD-N) and normal control subjects (n = 96). The T102C and the A-1438G polymorphisms are in complete linkage disequilibrium but not his452tyr. There was a significant excess of 102C and -1438G alleles (62.7%) in the SCZ-TD-Y patients compared to SCZ-TD-N patients (41.1%) and controls (45.9%; chi(2) = 12.8, df = 2, P = 0.002; SCZ-TD-Y vs SCZ-TD-N, chi(2) = 11.4, df = 1, P = 0.0008, OR 2.41, 95% CI 1.43-3.99) and of 102CC and -1438GG genotypes (SCZ-TD-Y 42.4%, SCZ-TD-N, 16.1%, controls 20.8%, chi(2) = 13.3, df = 4, P = 0.01). The 102CC and the -1438GG genotypes were associated with significantly higher AIMS trunk dyskinesia scores (F = 3.9; df = 2, 116; P = 0.02) and more incapacitation (F = 5.0; df = 2, 115; P = 0.006). The his452tyr polymorphism showed no association with TD. These findings suggest that the 5-HT2A receptor gene is significantly associated with susceptibility to TD in patients with chronic schizophrenia. Previously reported association of the T102C and A-1438G polymorphisms with schizophrenia(6) may reflect association of a sub-group of patients with a susceptibility to abnormal involuntary movements related to antipsychotic drug exposure.

Triiodothyronine augmentation of selective serotonin reuptake inhibitors in posttraumatic stress disorder

BACKGROUND

There is considerable comorbidity of major depression and posttraumatic stress disorder (PTSD), and antidepressants have been reported to be effective in treating PTSD. Addition of triiodothyronine (T3) to ongoing antidepressant treatment is considered an effective augmentation strategy in refractory depression. We report the effect of T3 augmentation of antidepressants in patients with PTSD.

METHOD

T3 (25 microg/day) was added to treatment with a selective serotonin reuptake inhibitor (SSRI) (paroxetine or fluoxetine, 20 mg/day for at least 4 weeks and 40 mg/day for a further 4 weeks) of 5 patients who fulfilled DSM-IV criteria for PTSD but not for major depressive disorder (although all patients had significant depressive symptoms). The Clinician-Administered PTSD Scale, the 21-item Hamilton Rating Scale for Depression, and the Clinical Global Impressions-Severity of Illness scale were administered every 2 weeks, and self-assessments were performed with a 100 mm visual analog mood scale.

RESULTS

In 4 of the 5 patients, partial clinical improvement was observed with SSRI treatment at a daily dose of 20 mg with little further improvement when the dose was raised to 40 mg/day. This improvement was substantially enhanced by the addition of T3. Improvement was most striking on the Hamilton Rating Scale for Depression.

CONCLUSION

T3 augmentation of SSRI treatment may be of therapeutic benefit in patients with PTSD, particularly those with depressive symptoms. Larger samples and controlled studies are needed in order to confirm this observation.

Functional effects of corticosterone on 5-HT(1A) and 5-HT(1B) receptor activity in rat brain: in vivo microdialysis studies

Glucocorticoid hormones are known to be elevated in depression, and to interact with serotonin 5-HT(1A) receptors at both the presynaptic and postsynaptic levels. Since one of the presumed mechanisms of action of antidepressant drugs is induction of changes in sensitivity of 5-HT(1A) and also 5-HT(1B) receptors, the effects of repeated administration of corticosterone (50 mg/kg s.c. b.i.d. for 10 days) on activities of these receptors were determined using in vivo microdialysis in freely moving rats. Presynaptic 5-HT(1A) receptor activity, as measured by the effect of a challenge dose (0.2 mg/kg s.c.) of the 5-HT(1A) agonist 8-hydroxy-2 (di-n-propylamino) tetralin (8-OH-DPAT) to reduce 5-HT levels in the hypothalamus, was not affected by corticosterone administration. Presynaptic 5-HT(1B) receptor activity, as measured by the effect of the 5-HT(1B) receptor antagonist (N-[4-methoxy-3-(4-methyl-1-piperizinyl)phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazole-3-yl)[1,1'-biphenyl]-carboxamide (GR 127935) (5 mg/kg s.c.) to increase 5-HT levels, was increased in hypothalamus but not hippocampus of corticosterone-treated rats. Postsynaptic 5-HT(1A) receptor activity, as measured by the effect of 8-OH-DPAT to increase cyclic AMP levels in the hippocampus, was not affected by corticosterone administration. The decrease in presynaptic 5-HT(1B) receptor activity after chronic administration of antidepressant drugs complements the increases in 5-HT(1B) receptor number observed in animal models of depression.

Increased prevalence of negative life events in subtypes of major depressive disorder

The prevalence of negative life events is known to be increased among patients with depression. Little data exist on the specific subtypes of depression that are related to negative life events. Our study aimed to address this issue. We compare 115 patients with major depressive disorder (MDD) to 60 normal controls. MDD patients reported experiencing one (P = .0001) or two (P = .01) negative life events more frequently than controls. Patients reported marital, other personal problems, and medical events significantly more often than controls (P < .01). Patients did not report more positive life events, and did not attribute greater severity to their adversities than controls. Younger MDD patients experienced four (P = .01) negative life events significantly more often than older patients. Similarly, patients with mild-moderate depression, nonmelancholic depression, or first episode of depression (FDE), respectively, experienced three or four life events significantly more often than patients with severe, melancholic, or recurrent depression (RDE). Other patient and illness characteristics such as gender, early parental loss, family history of depression or other mental disorders, psychotic features, suicide attempts, and chronicity were not related to increased prevalence of negative life events. Our results support the hypothesis that a subset of patients with MDD is especially prone to suffer from a cluster of negative life events. This subgroup is at increased risk for relapse and poor prognosis. The implications of these results for further research and for treatment are discussed.

Association between the serotonin 2C receptor gene and tardive dyskinesia in chronic schizophrenia: additive contribution of 5-HT2Cser and DRD3gly alleles to susceptibility

RATIONALE

Tardive dyskinesia (TD) is a longterm adverse effect of dopamine receptor blockers. The dopamine D3 receptor gene (DRD3) ser9gly polymorphism has been previously associated with susceptibility to TD. Serotonin receptor antagonism has been proposed as a common mechanism contributing to the low extra-pyramidal effects profile of atypical antipsychotic drugs.

OBJECTIVES

To examine the association of a functional polymorphism in the 5-HT2C receptor gene (HT2CR) with TD and the joint contribution of HT2CR and DRD3 to susceptibility.

METHODS

Case control association analysis of allele and genotype frequencies among schizophrenia patients with (n=55) and without TD (n=60), matched for antipsychotic drug exposure and other relevant variables, and normal control subjects (n=97). Parametric analyses of the contribution of 5-HT2Cser and DRD3gly alleles to dyskinesia scores.

RESULTS

We found a significant excess of 5-HT2Cser alleles in schizophrenia patients with TD (27.2%) compared to patients without TD (14.6%) and normal controls (14.2%; chi2=6.4, df 2, P=0.03) which was due to the female patients (chi2=8.6, df 2, P=0.01). Among the female TD patients there was an excess of cys-ser and ser-ser genotypes (chi2= 11.9, df 4, P=0.02). Analysis of covariance (ANCOVA), controlling for age at first antipsychotic treatment, revealed a significant effect of 5-HT2C genotype on orofacial dyskinesia (OFD) scores (F=3.47, df 2, P=.03). In a stepwise multiple regression analysis, 5-HT2C and DRD3 genotype (5-HT2Cser and DRD3gly allele carriage) respectively contributed 4.2% and 4.7% to the variance in OFD scores.

CONCLUSIONS

These findings support a small but significant contribution of the HT2CR and DRD3 to susceptibility to TD, which is additive in nature.

A genome-wide autosomal screen for schizophrenia susceptibility loci in 71 families with affected siblings: support for loci on chromosome 10p and 6

Evidence from epidemiological studies and segregation analysis suggests oligo- or polygenic inheritance in schizophrenia. Since model independent methods are thought to be most appropriate for linkage analysis in complex disorders, we performed a genome-wide autosomal screen in 71 families from Germany and Israel containing 86 independent affected sib-pairs with parental genotype information for statistical analysis strictly identity by descent. We genotyped 305 individuals with 463 markers at an average distance of approximately 10 cM genome-wide, and 1-2 cM in candidate regions (5q, 6p, q, 8p, 10p, 18p, 22q). The highest multipoint LOD scores (ASPEX) were obtained on 6p (D6S260, LOD = 2.0; D6S274, LOD = 2.2, MHC region, LOD = 2.15) and on 10p (D10S1714, LOD = 2.1), followed by 5q (D5S2066, LOD = 1.36), 6q (D6S271, LOD = 1.12; D6S1613, LOD = 1.11), 1q (D1S2675, LOD = 1.04), and 18p (broad disease model: D18S1116, LOD = 1.0). One hundred and thirty-three additional family members were available for some of the families (extended families) and were genotyped for these regions. GENEHUNTER produced a maximum NPL of 3.3 (P = 0.001) for the MHC region and NPL of 3.13 (P = 0.0015) for the region on 10p. There is support for these regions by independent groups. In genome-wide TDT analysis (sTDT, implemented in ASPEX), no marker passed the significance level of 0.0001 given by multiple testing, but nominal significance values for D10S211 (P = 0.03) and for GOLF (P = 0.0032) support further the linkage results on 10p and 18p. Our survey of 22 chromosomes identified candidate regions which should be useful to screen for schizophrenia susceptibility genes.

Chronic repetitive transcranial magnetic stimulation induces subsensitivity of presynaptic serotonergic autoreceptor activity in rat brain

Repetitive transcranial magnetic stimulation (rTMS) is a novel procedure which has proven effective in the treatment of major depression. We administered rTMS chronically to rats in order to determine whether this procedure affected serotonergic neurotransmission in the prefrontal cortex. Basal 5-HT levels, and the effects of challenges with the 5-HT1A receptor agonist 8-OH-DPAT and the 5-HT1B antagonist GR 127935 on 5-HT levels were determined using in vivo microdialysis. Rats which had undergone chronic rTMS showed reduced responses to both challenges, indicating subsensitivity of both the presynaptic 5-HT1A autoreceptors situated somatodendritically in the raphe nuclei and the 5-HT1B autoreceptors situated on nerve terminals. Since such subsensitivity has been demonstrated after other antidepressant treatments, our results indicate that these treatments and rTMS may have a common mechanism of action.

The impact of parental death versus separation from parents on the mental health of Israeli adolescents

Early research suggested that the loss of a parent during childhood can lead to depression and other psychopathology in children and adults. More recent research has differentiated between loss due to death and separation from parents and has questioned the link between early parental death and psychopathology. We examined the hypothesis that separation from parents has a more detrimental effect than the death of a parent on the mental health of adolescents in the community. Israeli adolescents (N = 844) with a mean age of 16.7 +/- 1.0 years (mean +/- SD) participated in this study. Seventy reported that a parent did not live at home during one of three 5-year periods until they reached the age of 15; 37 reported the death of a parent and 777 were from intact families. All participants completed the Brief Symptom Inventory (BSI), General Well Being Schedule (GWB), Parental Bonding Instrument (PBI), and Perceived Social Support Family/ Friends Scales (PSS-Fam and PSS-Fr). Adolescents who had experienced separation from parents had more psychiatric symptoms (BSI), expressed a lower sense of well-being (GWB), experienced less support from their family (PSS-Fam), and felt less cared for and more controlled by their parents (PBI) compared with those belonging to intact families. The death of a parent was not associated with significantly different scores on these variables. When we controlled for parental bonding (PBI) and perceived social support from family (PSS-Fam), the differences between the separation group and the intact family group were no longer significant. The psychological impact of separation from parents involves a greater risk for psychopathology than the death of a parent. The quality of the relationship with the parents moderates the negative impact of separation from them.

Multicenter linkage study of schizophrenia candidate regions on chromosomes 5q, 6q, 10p, and 13q: schizophrenia linkage collaborative group III

Schizophrenia candidate regions 33-51 cM in length on chromosomes 5q, 6q, 10p, and 13q were investigated for genetic linkage with mapped markers with an average spacing of 5.64 cM. We studied 734 informative multiplex pedigrees (824 independent affected sibling pairs [ASPs], or 1,003 ASPs when all possible pairs are counted), which were collected in eight centers. Cases with diagnoses of schizophrenia or schizoaffective disorder (DSM-IIIR criteria) were considered affected (n=1,937). Data were analyzed with multipoint methods, including nonparametric linkage (NPL), ASP analysis using the possible-triangle method, and logistic-regression analysis of identity-by-descent (IBD) sharing in ASPs with sample as a covariate, in a test for intersample heterogeneity and for linkage with allowance for intersample heterogeneity. The data most supportive for linkage to schizophrenia were from chromosome 6q; logistic-regression analysis of linkage allowing for intersample heterogeneity produced an empirical P value <.0002 with, or P=.0004 without, inclusion of the sample that produced the first positive report in this region; the maximum NPL score in this region was 2.47 (P=.0046), the maximum LOD score (MLS) from ASP analysis was 3.10 (empirical P=.0036), and there was significant evidence for intersample heterogeneity (empirical P=.0038). More-modest support for linkage was observed for chromosome 10p, with logistic-regression analysis of linkage producing an empirical P=. 045 and with significant evidence for intersample heterogeneity (empirical P=.0096).

Chronic clomipramine alters presynaptic 5-HT(1B) and postsynaptic 5-HT(1A) receptor sensitivity in rat hypothalamus and hippocampus, respectively

Clomipramine is a tricyclic antidepressant drug with a high affinity for the serotonin (5-HT) uptake site or transporter. Electrophysiological experiments have provided evidence that repeated administration of clomipramine induces an increase in the sensitivity of postsynaptic 5-HT(1A) receptors in the hippocampus. We have studied the effects of clomipramine, administered to rats at a dose of 10mg/kg/day for 28 days by osmotic minipumps, on presynaptic 5-HT(1A) and 5-HT(1B) autoreceptors in the hypothalamus, and on postsynaptic 5-HT(1A) receptors in the hippocampus, by using in vivo microdialysis to measure 5-HT and cyclic adenosine monophosphate (cAMP) levels. Postsynaptic 5-HT(1A) receptor sensitivity in the hypothalamus was determined by means of a neuroendocrine challenge procedure. Although the sensitivity of presynaptic 5-HT(1A) autoreceptors, as measured by the effect of a subcutaneous (s.c.) injection of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 0.2mg/kg or 50 microg/kg) to reduce 5-HT levels, did not change, there was a reduction in sensitivity of presynaptic 5-HT(1B) receptors, as measured by the effect of an injection of the 5-HT(1B/1D) antagonist GR 127935 (5mg/kg, s.c.) to increase 5-HT levels. This effect probably accounted for the increase in basal 5-HT levels observed in the hypothalamus after chronic clomipramine administration. Postsynaptic 5-HT(1A) receptor sensitivity in the hippocampus, measured by the effect of 8-OH-DPAT to increase cAMP levels in the dialysate, was increased after chronic clomipramine. Animals that had received daily intraperitoneal injections of 10mg/kg clomipramine for 28 days did not show a change in postsynaptic 5-HT(1A) receptor sensitivity in the hypothalamus as measured by the ability of 8-OH-DPAT (50 microg/kg, s.c.) to stimulate secretion of corticosterone. Taken together with the results of previous experiments involving the cerebral cortex, these in vivo results show that chronic clomipramine exerts effects on both pre- and postsynaptic serotonin receptors, but that these effects are highly region-specific.

Possible precipitants of psychiatric hospitalization in patients with major depression: results from the Jerusalem Collaborative Depression Project

In spite of substantial advances in the treatment of major depression by pharmacotherapy and other means, a significant number of depressed patients require hospitalization. In the context of the Jerusalem Collaborative Depression Project, possible precipitants of psychiatric hospitalization were sought in a cohort of patients (n = 107) who were admitted to hospitals in the Jerusalem area during a 14-month period because of a depressive episode. The patients fulfilled DSM III-R criteria for major depression, single or recurrent; bipolar 1 disorder, depressed or mixed; bipolar 2, depressed. The cohort encompassed more than two thirds of potential subjects admitted during this period with the ICD-9 equivalents of the specified diagnoses (as reported to the Israel Ministry of Health National Psychiatric Case Register) and were similar to the entire potential population in terms of their diagnostic breakdown. The patients underwent extensive socio-demographic and clinical evaluation that included detailed documentation of treatment received prior to hospitalization. Notwithstanding the absence of a comparison group of depressed patients who were not hospitalized, a number of potential precipitants were identified. These included older age (55.2% > 60 years, 20.6% > 70 years), immigration to Israel during the preceding 5 years (34.7%), concomitant physical illness (60%) which was associated with moderate to severe disability in 41% and poor quality of antidepressant pharmacotherapy prior to hospitalisation (only 24.3% received an adequate trial of antidepressant medication). Further evaluation of these and other potential factors could facilitate targeting of patient groups at particular risk for hospitalization and reduce the need for it.

Blunted temperature and cortisol responses to ipsapirone in major depression: lack of enhancement by electroconvulsive therapy

Depression has been shown in some studies to be associated with a reduction in hypothalamic 5-HT(1A) receptor function, as indicated by reduced hormone and/or hypothermic responses to 5-HT(1A) agonists such as ipsapirone. The hypothermic response to ipsapirone was reduced in depressed patients treated with amitriptyline. Hormone and hypothermic responses to 5-HT(1A) agonists were reduced in normal subjects administered specific serotonin reuptake inhibitors. Effects of electroconvulsive therapy (ECT) on 5-HT(1A) receptor-mediated responses in humans have not been reported. In the present work, ten depressed patients and 15 control subjects were challenged with placebo and with 0.3 mg/kg ipsapirone, administered 48 h apart in a randomised double blind design. Hypothermic, growth hormone (GH) and cortisol responses were measured. Seven of the depressed patients were treated with a course of ECT, and placebo and ipsapirone challenges were repeated 24 and 72 h after the last treatment. The cortisol response to ipsapirone was significantly reduced in the depressed patients compared with controls. The hypothermic response to ipsapirone was totally abolished in the depressed patients. When tested after a course of ECT, the seven depressed patients again showed reduced or blunted responses. We conclude that hypothalamic 5-HT(1A) receptor function is reduced in depression. In contrast to the effects of electroconvulsive shock (ECS) on post-synaptic 5-HT(1A) receptor function in animals, which have chiefly been measured in the hippocampus using electrophysiological techniques, ECT in humans does not induce an increase in sensitivity of post-synaptic 5-HT(1A) receptors in the hypothalamus.

Subchronic fluoxetine administration to rats: effects on 5-HT autoreceptor activity as measured by in vivo microdialysis

Subchronic administration of fluoxetine to rats has been shown to induce subsensitivity of presynaptic 5-HT(1A) and 5-HT(1B) autoreceptors, and also postsynaptic 5-HT(1A) receptors in the hypothalamus. We investigated the effects of administration of fluoxetine (10 mg/kg i.p.) to rats for 6 days on presynaptic 5-HT(1A) receptor activity in the hypothalamus, postsynaptic 5-HT(1A) receptor activity in the hippocampus, and presynaptic 5-HT(1B) autoreceptor activity in both areas, using in vivo microdialysis. The effect of the 5-HT(1B/1D) antagonist (N-[4-methoxy-3-(4-methyl-1-piperizinyl)phenyl]-2'-methyl-4'-(5- methyl-1,2,4-oxadiazole-3-yl)[1,1'-biphenyl]-carboxamide (GR 127935) (5 mg/kg s.c.) to elevate 5-hydroxytryptamine (5-HT) levels was reduced in hippocampus but not hypothalamus of fluoxetine-treated rats. Fluoxetine did not alter either presynaptic 5-HT(1A) autoreceptor activity, as measured by the effect of injection of 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) (0.2 mg/kg or 50 microg/kg s.c.) on 5-HT levels in the hypothalamus, or postsynaptic 5-HT(1A) receptor activity, as measured by the effect of 8-OH-DPAT (0.2 mg/kg s.c.) on cyclic AMP accumulation, in the hippocampus.

Balancing speed of response to ECT in major depression and adverse cognitive effects: role of treatment schedule

Schedule of administration (number of ECT per week and total number of treatments in the course) is one of a number of factors that may significantly influence the degree of cognitive impairment induced by ECT. We examined the effect of twice (ECT x 2) versus three times weekly (ECT x 3) bilateral ECT on cognitive function, particularly memory, in patients with major depression. Two studies were conducted, both double blind and controlled by the administration of simulated ECT (anesthesia and muscle relaxant only with no electrical stimulation). The results of these studies showed that the antidepressant effect of the two schedules, when assessed at the end of the ECT course, was equal. Speed of response was significantly greater with ECT x 3 but this schedule induced more severe memory impairment, even when the number of ECT in the series was not significantly different between the two groups. These findings are in general accordance with other studies that were similar in design although not as rigorously controlled. They support the conclusion that ECT x 2 is the more appropriate schedule for regular clinical practice unless speed of response is an overriding concern. In an era when patients administered ECT tend to be older and are more likely to manifest cognitive impairment for other reasons, choice of schedule is of particular relevance along with other factors such as electrode placement and stimulus intensity that influence ECT-induced cognitive impairment.

Association between obsessive-compulsive disorder and polymorphisms of genes encoding components of the serotonergic and dopaminergic pathways

Obsessive-compulsive disorder (OCD) is a severe and disabling anxiety disorder with a marked genetic contribution. Pharmacological data indicated involvement of the serotonergic and dopaminergic systems. We studied the association between OCD and six candidate genes encoding important components of the serotonergic and dopaminergic pathways in 75 biologically unrelated patients and 172 ethnically matched controls (Ashkenazi and non-Ashkenazi Jews). Polymorphisms in the following genes were studied: tryptophan hydroxylase (TPH), serotonin 2A receptor (HTR2A), serotonin 2C receptor (HTR2C), serotonin transporter (5-HTT), dopamine receptor D4 (DRD4), and dopamine transporter (DAT1). The genotypic and allelic distribution of all polymorphisms tested did not show statistically significant differences between patients and controls. Our results suggest that these polymorphisms do not play a major role in the genetic predisposition to OCD, although a minor contribution cannot be ruled out.