The iPSYCH2012 case-cohort sample: new directions for unravelling genetic and environmental architectures of severe mental disorders.

The Integrative Psychiatric Research (iPSYCH) consortium has established a large Danish population-based Case-Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born between 1981 and 2005, including 1 472 762 persons. This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3540), autism (N=16 146), attention-deficit/hyperactivity disorder (N=18 726) and affective disorder (N=26 380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30 000). Within the sample of 86 189 individuals, a total of 57 377 individuals had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information, and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders.

Efficacy of anti-inflammatory treatment on major depressive disorder or depressive symptoms: meta-analysis of clinical trials.

BACKGROUND: No study has gathered evidence from all randomized clinical trials (RCTs) with anti-inflammatory drugs measuring antidepressant effects including a detailed assessment of side-effects and bias. METHODS: We performed a systematic review identifying RCTs published prior to January 1, 2018, studying antidepressant treatment effects and side-effects of pharmacological anti-inflammatory intervention in adults with major depressive disorder (MDD) or depressive symptoms. Outcomes were depression scores after treatment, remission, response, and side-effects. Pooled standard mean differences (SMD) and risk ratios (RR) including 95% confidence intervals (95%-CI) were calculated. RESULTS: We identified 36 RCTs, whereof 13 investigated NSAIDs (N = 4214), 9 cytokine inhibitors (N = 3345), seven statins (N = 1576), 3 minocycline (N = 151), 2 pioglitazone (N = 77), and 2 glucocorticoids (N = 59). Anti-inflammatory agents improved depressive symptoms compared to placebo as add-on in patients with MDD (SMD = -0.64; 95%-CI = -0.88, -0.40; I2  = 51%; N = 597) and as monotherapy (SMD = -0.41; 95%-CI = -0.60, -0.22; I2  = 93%, N = 8825). Anti-inflammatory add-on improved response (RR = 1.76; 95%-CI = 1.44-2.16; I2  = 16%; N = 341) and remission (RR = 2.14; 95%-CI = 1.03-4.48; I2  = 57%; N = 270). We found a trend toward an increased risk for infections, and all studies showed high risk of bias. CONCLUSION: Anti-inflammatory agents improved antidepressant treatment effects. Future RCTs need to include longer follow-up, identify optimal doses and subgroups of patients that can benefit from anti-inflammatory intervention.

Predicting mechanical restraint of psychiatric inpatients by applying machine learning on electronic health data.

OBJECTIVE: Mechanical restraint (MR) is used to prevent patients from harming themselves or others during inpatient treatment. The objective of this study was to investigate whether incident MR occurring in the first 3 days following admission could be predicted based on analysis of electronic health data available after the first hour of admission. METHODS: The dataset consisted of clinical notes from electronic health records from the Central Denmark Region and data from the Danish Health Registers from patients admitted to a psychiatric department in the period from 2011 to 2015. Supervised machine learning algorithms were trained on a randomly selected subset of the data and validated using an independent test dataset. RESULTS: A total of 5050 patients with 8869 admissions were included in the study. One hundred patients were mechanically restrained in the period between one hour and 3 days after the admission. A Random Forest algorithm predicted MR with an area under the curve of 0.87 (95% CI 0.79-0.93). At 94% specificity, the sensitivity was 56%. Among the ten strongest predictors, nine were derived from the clinical notes. CONCLUSIONS: These findings open for the development of an early warning system that may guide interventions to reduce the use of MR.

Home visits in the Danish High Risk and Resilience Study - VIA 7: assessment of the home environment of 508 7-year-old children born to parents diagnosed with schizophrenia or bipolar disorder.

OBJECTIVE: The home environment provided by the caregivers of a child is an influential single factor for development and well-being. We aimed to compare the quality of the home environment of children at familial high risk of schizophrenia or bipolar disorder with population-based controls. METHODS: Danish nationwide registers were used to retrieve a cohort of 522 7-year-old children of parents diagnosed with schizophrenia (N = 202), bipolar disorder (N = 120) or none of these diagnoses (N = 200). The home environment was assessed using the Middle Childhood-Home Observation for Measurement of the Environment Inventory (MC-HOME Inventory). RESULTS: The proportion of children living in home environments that were evaluated not to meet the needs of a 7-year-old child was significantly larger in the two familial high-risk groups. This was true for 21% of the children with familial predisposition for schizophrenia and 7% of children with familial disposition for bipolar disorder. CONCLUSION: Children born to parents diagnosed with schizophrenia and to a lesser extent bipolar disorder are at an increased risk of growing up in a home environment with an insufficient level of stimulation and support. Identifying families with inadequate home environments is a necessary step towards specialized help and support to at-risk families.

Schizophrenia and attendance in primary healthcare: a population-based matched cohort study.

Objective: Schizophrenia is associated with high mortality, somatic comorbidity and reduced life expectancy. The general practitioner (GP) plays a key role in the treatment of mental and physical multimorbidity. Nevertheless, it is unclear how much individuals with schizophrenia use primary healthcare. This study aims to investigate the yearly numbers of consultations in general practice for individuals with schizophrenia. Design and Setting: We performed a population-based matched cohort study of 21,757 individuals with schizophrenia and 435,140 age- and gender-matched references from Danish National Registers. Monthly general practice consultations were analysed using a generalized linear model with log link and assuming negative binomial distribution. Main outcome measures: Consultation rates in general practice up to17 years after index diagnosis. Results: Individuals with schizophrenia attended their GP more than references throughout the study period. The cases had 82% (95% CI: 78-87) and 76% (95% CI: 71-80) more consultations in primary care after 1 year and 5 years, respectively. Individuals with both schizophrenia and comorbid somatic illness attended even more. Conclusion: Individuals with schizophrenia are in regular contact with their GP, especially if they have comorbid illnesses. Whether an average of six consultations per year for individuals with schizophrenia is sufficient is up for debate. The study demonstrates a potential for an increased prevention and treatment of individuals with schizophrenia in general practice. KEY POINTS Schizophrenia is associated with high mortality, somatic comorbidity and reduced life expectancy. Little is known about the attendance pattern in primary care for individuals with schizophrenia. •We found high attendance rates in primary care for individuals diagnosed with schizophrenia from index diagnosis and at least 17 years after diagnosis, which suggests opportunities for earlier intervention to improve their somatic health. •We found an association between high illness comorbidity and increased risk of not attending the general practitioner. The most severely somatically and mentally ill individuals may thus be difficult to reach and support in the current healthcare system.

New insights into the pharmacogenomics of antidepressant response from the GENDEP and STAR*D studies: rare variant analysis and high-density imputation.

Genome-wide association studies have generally failed to identify polymorphisms associated with antidepressant response. Possible reasons include limited coverage of genetic variants that this study tried to address by exome genotyping and dense imputation. A meta-analysis of Genome-Based Therapeutic Drugs for Depression (GENDEP) and Sequenced Treatment Alternatives to Relieve Depression (STAR*D) studies was performed at the single-nucleotide polymorphism (SNP), gene and pathway levels. Coverage of genetic variants was increased compared with previous studies by adding exome genotypes to previously available genome-wide data and using the Haplotype Reference Consortium panel for imputation. Standard quality control was applied. Phenotypes were symptom improvement and remission after 12 weeks of antidepressant treatment. Significant findings were investigated in NEWMEDS consortium samples and Pharmacogenomic Research Network Antidepressant Medication Pharmacogenomic Study (PGRN-AMPS) for replication. A total of 7062 950 SNPs were analyzed in GENDEP (n=738) and STAR*D (n=1409). rs116692768 (P=1.80e-08, ITGA9 (integrin α9)) and rs76191705 (P=2.59e-08, NRXN3 (neurexin 3)) were significantly associated with symptom improvement during citalopram/escitalopram treatment. At the gene level, no consistent effect was found. At the pathway level, the Gene Ontology (GO) terms GO: 0005694 (chromosome) and GO: 0044427 (chromosomal part) were associated with improvement (corrected P=0.007 and 0.045, respectively). The association between rs116692768 and symptom improvement was replicated in PGRN-AMPS (P=0.047), whereas rs76191705 was not. The two SNPs did not replicate in NEWMEDS. ITGA9 codes for a membrane receptor for neurotrophins and NRXN3 is a transmembrane neuronal adhesion receptor involved in synaptic differentiation. Despite their meaningful biological rationale for being involved in antidepressant effect, replication was partial. Further studies may help in clarifying their role.

The role of genetic liability in the association of urbanicity at birth and during upbringing with schizophrenia in Denmark.

BACKGROUND: Studies have indicated that the association of urbanicity at birth and during upbringing with schizophrenia may be driven by familial factors such as genetic liability. We used a population-based nested case-control study to assess whether polygenic risk score (PRS) for schizophrenia was associated with urbanicity at birth and at age 15, and to assess whether PRS and parental history of mental disorder together explained the association between urbanicity and schizophrenia. METHODS: Data were drawn from Danish population registries. Cases born since 1981 and diagnosed with schizophrenia between 1994 and 2009 were matched to controls with the same sex and birthdate (1549 pairs). Genome-wide data were obtained from the Danish Neonatal Screening Biobank and PRSs were calculated based on results of a separate, large meta-analysis. RESULTS: Those with higher PRS were more likely reside in the capital compared with rural areas at age 15 [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.01-1.40], but not at birth (OR 1.09, 95% CI 0.95-1.26). Adjustment for PRS produced almost no change in relative risks of schizophrenia associated with urbanicity at birth, but slightly attenuated those for urban residence at age 15. Additional adjustment for parental history led to slight attenuation of relative risks for urbanicity at birth [incidence rate ratio (IRR) for birth in capital = 1.54, 95% CI 1.18-2.02; overall p = 0.016] and further attenuation of relative risks for urbanicity at age 15 (IRR for residence in capital = 1.32, 95% CI 0.97-1.78; overall p = 0.148). CONCLUSIONS: While results regarding urbanicity during upbringing were somewhat equivocal, genetic liability as measured here does not appear to explain the association between urbanicity at birth and schizophrenia.

The validity and sensitivity of PANSS-6 in treatment-resistant schizophrenia.

OBJECTIVE: To test the validity and sensitivity of the six-item version (PANSS-6) of the 30-item Positive and Negative Syndrome Scale (PANSS-30) in treatment-resistant schizophrenia (TRS). METHOD: Using data from the clozapine phase (2E) of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study, we investigated the following: (i) The scalability of PANSS-6 and PANSS-30; (ii) The correlation between PANSS-6 and PANSS-30 total scores; (iii) Whether PANSS-6 could identify cross-sectional symptom remission; and (iv) The efficacy of clozapine, olanzapine, risperidone and quetiapine in TRS using the 'speed of change' on PANSS-6 and PANSS-30 (change in total score per week) as outcome measures. RESULTS: We found that (i) only PANSS-6 and not PANSS-30 was scalable; (ii) The correlation between PANSS-6 and PANSS-30 total scores was high (Spearman coefficient: 0.85), (iii) PANSS-6 accurately identified cross-sectional symptom remission as defined by the Andreasen et al. criteria; and (iv) The only antipsychotic that caused improvement (speed of change significantly lower than 0 during the first three months of treatment) was clozapine, both when using PANSS-6 (speed of change: -0.50 points/week; 95%CI: -0.84, -0.17) and PANSS-30 (speed of change: -1.41 points/week; 95%CI: -2.80, -0.02) as outcome measures. CONCLUSION: PANSS-6 validly measures severity, remission and antipsychotic efficacy in TRS.

Familial confounding of the association between maternal smoking during pregnancy and internalizing disorders in offspring.

BACKGROUND: Maternal smoking has consistently been associated with multiple adverse childhood outcomes including externalizing disorders. In contrast the association between maternal smoking during pregnancy (MSDP) and internalizing (anxiety and depressive) disorders in offspring has received less investigation. METHOD: We conducted a nationwide cohort study including 957635 individuals born in Denmark between 1991 and 2007. Data on MSDP and diagnoses of depression or anxiety disorders were derived from national registers and patients were followed up from the age of 5 years to the end of 2012. Hazard rate ratios (HRRs) were estimated using stratified Cox regression models. Sibling data were used to disentangle individual- and familial-level effects of MSDP and to control for unmeasured familial confounding. RESULTS: At the population level, offspring exposed to MSDP were at increased risk for both severe depression [HRR 1.29, 95% confidence interval (CI) 1.22-1.36] and severe anxiety disorders (HRR 1.26, 95% CI 1.20-1.32) even when controlling for maternal and paternal traits. However, there was no association between MSDP and internalizing disorders when controlling for the mother's propensity for MSDP (depression: HRR 1.11, 95% CI 0.94-1.30; anxiety disorders: HRR 0.94, 95% CI 0.80-1.11) or comparing differentially exposed siblings (depression: HRR 1.18, 95% CI 0.75-1.89; anxiety disorders: HRR 0.87, 95% CI 0.55-1.36). CONCLUSIONS: The results suggest that familial background factors account for the association between MSDP and severe internalizing disorders not the specific exposure to MSDP.

Stability and development of psychotic symptoms and the use of antipsychotic medication - long-term follow-up.

BACKGROUND: Few studies have evaluated the development in the use of antipsychotic medication and psychotic symptoms in patients with first-episode psychosis on a long-term basis. Our objective was to investigate how psychotic symptoms and the use of antipsychotic medication changed over a 10-year period in a cohort of patients with first-episode psychosis. METHOD: The study is a longitudinal prospective cohort study over 10 years with follow-ups at years 1, 2, 5 and 10. A total of 496 patients with first-episode psychosis were included in a multi-centre study initiated between 1998 and 2000 in Copenhagen and Aarhus, Denmark. RESULTS: At all follow-ups, a large proportion (20-30%) of patients had remission of psychotic symptoms without use of antipsychotic medication at the time of the follow-up. Patients who were in this group at the 5-year follow-up had an 87% [95% confidence interval (CI) 77-96%] chance of being in the same group at the 10-year follow-up. This stability was also the case for patients who had psychotic symptoms and were treated with antipsychotic medication at year 5, where there was a 67% (95% CI 56-78%) probability of being in this group at the consecutive follow-up. CONCLUSIONS: A large group of patients with psychotic illness were in remission without the use of antipsychotic medication, peaking at year 10. Overall there was a large degree of stability in disease courses over the 10-year period. These results suggest that the long-term outcome of psychotic illness is heterogeneous and further investigation on a more individualized approach to long-term treatment is needed.

Candidate genes in panic disorder: meta-analyses of 23 common variants in major anxiogenic pathways.

The utilization of molecular genetics approaches in examination of panic disorder (PD) has implicated several variants as potential susceptibility factors for panicogenesis. However, the identification of robust PD susceptibility genes has been complicated by phenotypic diversity, underpowered association studies and ancestry-specific effects. In the present study, we performed a succinct review of case-control association studies published prior to April 2015. Meta-analyses were performed for candidate gene variants examined in at least three studies using the Cochrane Mantel-Haenszel fixed-effect model. Secondary analyses were also performed to assess the influences of sex, agoraphobia co-morbidity and ancestry-specific effects on panicogenesis. Meta-analyses were performed on 23 variants in 20 PD candidate genes. Significant associations after correction for multiple testing were observed for three variants, TMEM132D rs7370927 (T allele: odds ratio (OR)=1.27, 95% confidence interval (CI): 1.15-1.40, P=2.49 × 10(-6)), rs11060369 (CC genotype: OR=0.65, 95% CI: 0.53-0.79, P=1.81 × 10(-5)) and COMT rs4680 (Val (G) allele: OR=1.27, 95% CI: 1.14-1.42, P=2.49 × 10(-5)) in studies with samples of European ancestry. Nominal associations that did not survive correction for multiple testing were observed for NPSR1 rs324891 (T allele: OR=1.22, 95% CI: 1.07-1.38, P=0.002), TPH1 rs1800532 (AA genotype: OR=1.46, 95% CI: 1.14-1.89, P=0.003) and HTR2A rs6313 (T allele: OR=1.19, 95% CI: 1.07-1.33, P=0.002) in studies with samples of European ancestry and for MAOA-uVNTR in female PD (low-active alleles: OR=1.21, 95% CI: 1.07-1.38, P=0.004). No significant associations were observed in the secondary analyses considering sex, agoraphobia co-morbidity and studies with samples of Asian ancestry. Although these findings highlight a few associations, PD likely involves genetic variation in a multitude of biological pathways that is diverse among populations. Future studies must incorporate larger sample sizes and genome-wide approaches to further quantify the observed genetic variation among populations and subphenotypes of PD.

High loading of polygenic risk in cases with chronic schizophrenia.

Genomic risk profile scores (GRPSs) have been shown to predict case-control status of schizophrenia (SCZ), albeit with varying sensitivity and specificity. The extent to which this variability in prediction accuracy is related to differences in sampling strategies is unknown. Danish population-based registers and Neonatal Biobanks were used to identify two independent incident data sets (denoted target and replication) comprising together 1861 cases with SCZ and 1706 controls. A third data set was a German prevalent sample with diagnoses assigned to 1773 SCZ cases and 2161 controls based on clinical interviews. GRPSs were calculated based on the genome-wide association results from the largest SCZ meta-analysis yet conducted. As measures of genetic risk prediction, Nagelkerke pseudo-R(2) and variance explained on the liability scale were calculated. GRPS for SCZ showed positive correlations with the number of psychiatric admissions across all P-value thresholds in both the incident and prevalent samples. In permutation-based test, Nagelkerke pseudo-R(2) values derived from samples enriched for frequently admitted cases were found to be significantly higher than for the full data sets (Ptarget=0.017, Preplication=0.04). Oversampling of frequently admitted cases further resulted in a higher proportion of variance explained on the liability scale (improvementtarget= 50%; improvementreplication= 162%). GRPSs are significantly correlated with chronicity of SCZ. Oversampling of cases with a high number of admissions significantly increased the amount of variance in liability explained by GRPS. This suggests that at least part of the effect of common single-nucleotide polymorphisms is on the deteriorative course of illness.

Infections and exposure to anti-infective agents and the risk of severe mental disorders: a nationwide study.

OBJECTIVE: Severe infections are associated with increased risks of mental disorders; however, this is the first large-scale study investigating whether infections treated with anti-infective agents in the primary care setting increase the risks of schizophrenia and affective disorders. METHOD: We identified all individuals born in Denmark 1985-2002 (N = 1 015 447) and studied the association between infections treated with anti-infective agents and the subsequent risk of schizophrenia and affective disorders during 1995-2013. Cox regression analyses were adjusted for important confounders. RESULTS: Infections treated with anti-infective agents were associated with increased risks of schizophrenia by a hazard rate ratio (HRR) of 1.37 (95%-CI = 1.20-1.57) and affective disorders by a HRR of 1.64 (95%-CI = 1.48-1.82), fitting a dose-response and temporal relationship (P < 0.001). The excess risk was primarily driven by infections treated with antibiotics, whereas infections treated with antivirals, antimycotics, and antiparasitic agents were not significant after mutual adjustment. Individuals with infections requiring hospitalization had the highest risks for schizophrenia (HRR = 2.05; 95%-CI = 1.77-2.38) and affective disorders (HRR = 2.59; 95%-CI = 2.31-2.89). CONCLUSION: Infections treated with anti-infective agents and particularly infections requiring hospitalizations were associated with increased risks of schizophrenia and affective disorders, which may be mediated by effects of infections/inflammation on the brain, alterations of the microbiome, genetics, or other environmental factors.

COMT Val158Met and MTHFR C677T moderate risk of schizophrenia in response to childhood adversity.

OBJECTIVE: Mesolimbic dopamine sensitization has been hypothesized to be a mediating factor of childhood adversity (CA) on schizophrenia risk. Activity of catechol-O-methyltransferase (COMT) Val158Met increases mesolimbic dopamine signaling and may be further regulated by methylenetetrahydrofolate reductase (MTHFR) C677T. This study investigates the three-way interaction between CA, COMT, and MTHFR. METHODS: We conducted a nested case-control study on individuals born after 1981, linking population-based registers to study the three-way interaction. We included 1699 schizophrenia cases and 1681 controls, and used conditional logistic regression to report incidence rate ratios (IRRs). RESULTS: Childhood adversity was robustly associated with schizophrenia. No main genetic effects were observed. MTHFR C677T increased schizophrenia risk in a dose-dependent manner per MTHFR T allele (P = 0.005) consequent upon CA exposure. After inclusion of the significant (P = 0.03) COMT × MTHFR × CA interaction, the risk was further increased per high-activity COMT Val allele. Hence, exposed COMT Val/Val and MTHFR T/T carriers had an IRR of 2.76 (95% CI, 1.66-4.61). Additional adjustments for ancestry and parental history of mental illness attenuated the results with the interaction being only marginally significant. CONCLUSION: MTHFR C677T and COMT Val158Met interact with CA to increase risk of schizophrenia.

PANSS-6: a brief rating scale for the measurement of severity in schizophrenia.

OBJECTIVE: The 30-item Positive and Negative Syndrome Scale (PANSS-30) is the most widely used rating scale in schizophrenia, but too long for clinical use. Shorter PANSS versions have been proposed, including the PANSS-14 and PANSS-8. However, none of these PANSS versions has been validated using the parametric Rasch rating scale model, which evaluates 'scalability'. Scalability means that each item in a rating scale provides unique information regarding syndrome severity and is a statistical prerequisite for using the total score as a measure of overall severity. METHOD: Based on data from two randomized placebo-controlled trials in schizophrenia, we tested the scalability of PANSS-30, PANSS-14 and PANSS-8 by means of the parametric Rasch rating scale model. Furthermore, we tested whether a scalable PANSS version could separate efficacy of haloperidol and sertindole from placebo. RESULTS: Neither PANSS-30, PANSS-14 nor PANSS-8 was scalable. However, PANSS-6, consisting of the items: P1-Delusions, P2-Conceptual disorganization, P3-Hallucinations, N1-Blunted Affect, N4-Social withdrawal, N6-Lack of spontaneity and flow of conversation, was scalable. Furthermore, PANSS-6 captured superior symptom reduction and higher remission rates during treatment with haloperidol and sertindole vs. placebo. CONCLUSION: PANSS-6 is a short schizophrenia severity rating scale that adequately separates antipsychotic efficacy from that of placebo.

Increased use of primary care during 6 years of prodromal schizophrenia.

BACKGROUND: Early diagnosis is important for the course of schizophrenia. AIM: To investigate whether prodromal symptoms of schizophrenia lead to increased use of primary care. METHOD: A register-based cohort study of 21 894 cases with incident schizophrenia and 437 880 matched controls. RESULTS: Cases used daytime primary care 43% more than controls during the 6 years before diagnosis (IRR = 1.43; 95% CI: 1.39; 1.48) and 132% more during the last 2 months (IRR = 2.32; 95% CI: 2.27; 2.37), and 34% (IRR = 1.34; 95% CI: 1.23; 1.48) vs. 374% more for out-of-hours services (IRR = 3.74; 95% CI: 3.52; 3.98). Six years before index diagnosis, 30% of cases had at least one psychiatric contact without being diagnosed with schizophrenia, increasing to 75% 1 month before diagnosis. CONCLUSION: Increased help-seeking behaviour was seen at least 6 years before index diagnosis, suggesting a 'window' for earlier diagnosis of prodromal schizophrenia.

Gender-age interaction in incidence rates of childhood emotional disorders.

BACKGROUND: The post-pubertal association of female gender with emotional disorder is a robust finding. However, studies exploring the association of gender and emotional disorders before puberty are few and present diverging results. The aim of this study was to present gender-specific incidence rates of emotional disorders throughout childhood. METHOD: This is a population-based cohort study of 907,806 Danish 3- to 18-year-olds. The outcome was assignment of an emotional disorder diagnosis based on in-patient and out-patient data from The Danish Psychiatric Central Register. Outcome measures were incidence rates and cumulative incidences for unipolar depressive disorder (ICD-10: F32-F33), anxiety disorders (ICD-10: F40-F42), and emotional disorders with onset specific to childhood (ICD-10: F93). RESULTS: Pre-pubertal incidence rates for depressive and anxiety disorders were higher for boys than girls. At age 12 years the pattern reversed. The cumulative incidence for any emotional disorder (F32-F33, F40-F42, F93) on the 11th birthday was 0.52% (95% CI 0.50-0.55) for boys and 0.31% (95% CI 0.29-0.33) for girls. On the 19th birthday cumulative incidence was 2.33% (95% CI 2.24-2.43) for boys and 3.77% (95% CI 3.64-3.90) for girls. The pre-pubertal male preponderance was also significant for depressive disorders (F32-F33, p = 0.00144) and anxiety disorders (F40-F42, F93, p < 0.00001) separately. CONCLUSIONS: Emotional disorders seem to display a male preponderance before the age of 12 years and a female preponderance thereafter. Studies exploring this gender-age interaction are needed. Still, the results question the general assumption that females throughout the lifespan are more at risk for emotional disorders than males.

Familiality and SNP heritability of age at onset and episodicity in major depressive disorder.

BACKGROUND: Strategies to dissect phenotypic and genetic heterogeneity of major depressive disorder (MDD) have mainly relied on subphenotypes, such as age at onset (AAO) and recurrence/episodicity. Yet, evidence on whether these subphenotypes are familial or heritable is scarce. The aims of this study are to investigate the familiality of AAO and episode frequency in MDD and to assess the proportion of their variance explained by common single nucleotide polymorphisms (SNP heritability). METHOD: For investigating familiality, we used 691 families with 2-5 full siblings with recurrent MDD from the DeNt study. We fitted (square root) AAO and episode count in a linear and a negative binomial mixed model, respectively, with family as random effect and adjusting for sex, age and center. The strength of familiality was assessed with intraclass correlation coefficients (ICC). For estimating SNP heritabilities, we used 3468 unrelated MDD cases from the RADIANT and GSK Munich studies. After similarly adjusting for covariates, derived residuals were used with the GREML method in GCTA (genome-wide complex trait analysis) software. RESULTS: Significant familial clustering was found for both AAO (ICC = 0.28) and episodicity (ICC = 0.07). We calculated from respective ICC estimates the maximal additive heritability of AAO (0.56) and episodicity (0.15). SNP heritability of AAO was 0.17 (p = 0.04); analysis was underpowered for calculating SNP heritability of episodicity. CONCLUSIONS: AAO and episodicity aggregate in families to a moderate and small degree, respectively. AAO is under stronger additive genetic control than episodicity. Larger samples are needed to calculate the SNP heritability of episodicity. The described statistical framework could be useful in future analyses.

Genome-wide study of association and interaction with maternal cytomegalovirus infection suggests new schizophrenia loci.

Genetic and environmental components as well as their interaction contribute to the risk of schizophrenia, making it highly relevant to include environmental factors in genetic studies of schizophrenia. This study comprises genome-wide association (GWA) and follow-up analyses of all individuals born in Denmark since 1981 and diagnosed with schizophrenia as well as controls from the same birth cohort. Furthermore, we present the first genome-wide interaction survey of single nucleotide polymorphisms (SNPs) and maternal cytomegalovirus (CMV) infection. The GWA analysis included 888 cases and 882 controls, and the follow-up investigation of the top GWA results was performed in independent Danish (1396 cases and 1803 controls) and German-Dutch (1169 cases, 3714 controls) samples. The SNPs most strongly associated in the single-marker analysis of the combined Danish samples were rs4757144 in ARNTL (P=3.78 × 10(-6)) and rs8057927 in CDH13 (P=1.39 × 10(-5)). Both genes have previously been linked to schizophrenia or other psychiatric disorders. The strongest associated SNP in the combined analysis, including Danish and German-Dutch samples, was rs12922317 in RUNDC2A (P=9.04 × 10(-7)). A region-based analysis summarizing independent signals in segments of 100 kb identified a new region-based genome-wide significant locus overlapping the gene ZEB1 (P=7.0 × 10(-7)). This signal was replicated in the follow-up analysis (P=2.3 × 10(-2)). Significant interaction with maternal CMV infection was found for rs7902091 (P(SNP × CMV)=7.3 × 10(-7)) in CTNNA3, a gene not previously implicated in schizophrenia, stressing the importance of including environmental factors in genetic studies.

Copy number variants and therapeutic response to antidepressant medication in major depressive disorder.

It would be beneficial to find genetic predictors of antidepressant response to help personalise treatment of major depressive disorder (MDD). Rare copy number variants (CNVs) have been implicated in several psychiatric disorders, including MDD, but their role in antidepressant response has yet to be investigated. CNV data were available for 1565 individuals with MDD from the NEWMEDS (Novel Methods leading to New Medications in Depression and Schizophrenia) consortium with prospective data on treatment outcome with either a serotonergic or noradrenergic antidepressant. No association was seen between the presence of CNV (rare or common), the overall number of CNVs or genomic CNV 'burden' and antidepressant response. Specific CNVs were nominally associated with antidepressant response, including 15q13.3 duplications and exonic NRXN1 deletions. These were associated with poor response to antidepressants. Overall burden of CNVs is unlikely to contribute to personalising antidepressant treatment. Specific CNVs associated with antidepressant treatment require replication and further study to confirm their role in the therapeutic action of antidepressant.