Witte J. G. Hoogendijk

Identification of risk loci with shared effects on five major psychiatric disorders: a genome-wide analysis

BACKGROUND: Findings from family and twin studies suggest that genetic contributions to psychiatric disorders do not in all cases map to present diagnostic categories. We aimed to identify specific variants underlying genetic effects shared between the five disorders in the Psychiatric Genomics Consortium: autism spectrum disorder, attention deficit-hyperactivity disorder, bipolar disorder, major depressive disorder, and schizophrenia. METHODS: We analysed genome-wide single-nucleotide polymorphism (SNP) data for the five disorders in 33,332 cases and 27,888 controls of European ancestory. To characterise allelic effects on each disorder, we applied a multinomial logistic regression procedure with model selection to identify the best-fitting model of relations between genotype and phenotype. We examined cross-disorder effects of genome-wide significant loci previously identified for bipolar disorder and schizophrenia, and used polygenic risk-score analysis to examine such effects from a broader set of common variants. We undertook pathway analyses to establish the biological associations underlying genetic overlap for the five disorders. We used enrichment analysis of expression quantitative trait loci (eQTL) data to assess whether SNPs with cross-disorder association were enriched for regulatory SNPs in post-mortem brain-tissue samples. FINDINGS: SNPs at four loci surpassed the cutoff for genome-wide significance (p<5x10(-8)) in the primary analysis: regions on chromosomes 3p21 and 10q24, and SNPs within two L-type voltage-gated calcium channel subunits, CACNA1C and CACNB2. Model selection analysis supported effects of these loci for several disorders. Loci previously associated with bipolar disorder or schizophrenia had variable diagnostic specificity. Polygenic risk scores showed cross-disorder associations, notably between adult-onset disorders. Pathway analysis supported a role for calcium channel signalling genes for all five disorders. Finally, SNPs with evidence of cross-disorder association were enriched for brain eQTL markers. INTERPRETATION: Our findings show that specific SNPs are associated with a range of psychiatric disorders of childhood onset or adult onset. In particular, variation in calcium-channel activity genes seems to have pleiotropic effects on psychopathology. These results provide evidence relevant to the goal of moving beyond descriptive syndromes in psychiatry, and towards a nosology informed by disease cause. FUNDING: National Institute of Mental Health.BACKGROUND Findings from family and twin studies suggest that genetic contributions to psychiatric disorders do not in all cases map to present diagnostic categories. We aimed to identify specific variants underlying genetic effects shared between the five disorders in the Psychiatric Genomics Consortium: autism spectrum disorder, attention deficit-hyperactivity disorder, bipolar disorder, major depressive disorder, and schizophrenia. METHODS We analysed genome-wide single-nucleotide polymorphism (SNP) data for the five disorders in 33,332 cases and 27,888 controls of European ancestory. To characterise allelic effects on each disorder, we applied a multinomial logistic regression procedure with model selection to identify the best-fitting model of relations between genotype and phenotype. We examined cross-disorder effects of genome-wide significant loci previously identified for bipolar disorder and schizophrenia, and used polygenic risk-score analysis to examine such effects from a broader set of common variants. We undertook pathway analyses to establish the biological associations underlying genetic overlap for the five disorders. We used enrichment analysis of expression quantitative trait loci (eQTL) data to assess whether SNPs with cross-disorder association were enriched for regulatory SNPs in post-mortem brain-tissue samples. FINDINGS SNPs at four loci surpassed the cutoff for genome-wide significance (p<5×10(-8)) in the primary analysis: regions on chromosomes 3p21 and 10q24, and SNPs within two L-type voltage-gated calcium channel subunits, CACNA1C and CACNB2. Model selection analysis supported effects of these loci for several disorders. Loci previously associated with bipolar disorder or schizophrenia had variable diagnostic specificity. Polygenic risk scores showed cross-disorder associations, notably between adult-onset disorders. Pathway analysis supported a role for calcium channel signalling genes for all five disorders. Finally, SNPs with evidence of cross-disorder association were enriched for brain eQTL markers. INTERPRETATION Our findings show that specific SNPs are associated with a range of psychiatric disorders of childhood onset or adult onset. In particular, variation in calcium-channel activity genes seems to have pleiotropic effects on psychopathology. These results provide evidence relevant to the goal of moving beyond descriptive syndromes in psychiatry, and towards a nosology informed by disease cause. FUNDING National Institute of Mental Health.

The Netherlands Study of Depression and Anxiety (NESDA): rationale, objectives and methods.

The Netherlands Study of Depression and Anxiety (NESDA) is a multi‐site naturalistic cohort study to: (1) describe the long‐term course and consequences of depressive and anxiety disorders, and (2) to integrate biological and psychosocial research paradigms within an epidemiological approach in order to examine (interaction between) predictors of the long‐term course and consequences.

Major Depressive Disorder and Hypothalamic-Pituitary-Adrenal Axis Activity: Results From a Large Cohort Study

CONTEXT There is a central belief that depression is associated with hyperactivity of the hypothalamic-pituitary-adrenal axis, resulting in higher cortisol levels. However, results are inconsistent. OBJECTIVE To examine whether there is an association between depression and various cortisol indicators in a large cohort study. DESIGN, SETTING, AND PARTICIPANTS Data are from 1588 participants of the Netherlands Study of Depression and Anxiety who were recruited from the community, general practice care, and specialized mental health care. Three groups were compared: 308 control subjects without psychiatric disorders, 579 persons with remitted (no current) major depressive disorder (MDD), and 701 persons with a current MDD diagnosis, as assessed using the DSM-IV Composite International Diagnostic Interview. MAIN OUTCOME MEASURES Cortisol levels were measured in 7 saliva samples to determine the 1-hour cortisol awakening response, evening cortisol levels, and cortisol suppression after a 0.5-mg dexamethasone suppression test. RESULTS Both the remitted and current MDD groups showed a significantly higher cortisol awakening response compared with control subjects (effect size [Cohen d] range, 0.15-0.25). Evening cortisol levels were higher among the current MDD group at 10 pm but not at 11 pm. The postdexamethasone cortisol level did not differ between the MDD groups. Most depression characteristics (severity, chronicity, symptom profile, prior childhood trauma) were not associated with hypothalamic-pituitary-adrenal axis activity except for comorbid anxiety, which tended to be associated with a higher cortisol awakening response. The use of psychoactive medication was generally associated with lower cortisol levels and less cortisol suppression after dexamethasone ingestion. CONCLUSIONS This large cohort study shows significant, although modest, associations between MDD and specific hypothalamic-pituitary-adrenal axis indicators. Because a higher cortisol awakening response was observed among both subjects with current MDD and subjects with remitted MDD, this may be indicative of an increased biological vulnerability for depression.

Effect of Bright Light and Melatonin on Cognitive and Noncognitive Function in Elderly Residents of Group Care Facilities A Randomized Controlled Trial

CONTEXT Cognitive decline, mood, behavioral and sleep disturbances, and limitations of activities of daily living commonly burden elderly patients with dementia and their caregivers. Circadian rhythm disturbances have been associated with these symptoms. OBJECTIVE To determine whether the progression of cognitive and noncognitive symptoms may be ameliorated by individual or combined long-term application of the 2 major synchronizers of the circadian timing system: bright light and melatonin. DESIGN, SETTING, AND PARTICIPANTS A long-term, double-blind, placebo-controlled, 2 x 2 factorial randomized trial performed from 1999 to 2004 with 189 residents of 12 group care facilities in the Netherlands; mean (SD) age, 85.8 (5.5) years; 90% were female and 87% had dementia. INTERVENTIONS Random assignment by facility to long-term daily treatment with whole-day bright (+/- 1000 lux) or dim (+/- 300 lux) light and by participant to evening melatonin (2.5 mg) or placebo for a mean (SD) of 15 (12) months (maximum period of 3.5 years). MAIN OUTCOME MEASURES Standardized scales for cognitive and noncognitive symptoms, limitations of activities of daily living, and adverse effects assessed every 6 months. RESULTS Light attenuated cognitive deterioration by a mean of 0.9 points (95% confidence interval [CI], 0.04-1.71) on the Mini-Mental State Examination or a relative 5%. Light also ameliorated depressive symptoms by 1.5 points (95% CI, 0.24-2.70) on the Cornell Scale for Depression in Dementia or a relative 19%, and attenuated the increase in functional limitations over time by 1.8 points per year (95% CI, 0.61-2.92) on the nurse-informant activities of daily living scale or a relative 53% difference. Melatonin shortened sleep onset latency by 8.2 minutes (95% CI, 1.08-15.38) or 19% and increased sleep duration by 27 minutes (95% CI, 9-46) or 6%. However, melatonin adversely affected scores on the Philadelphia Geriatric Centre Affect Rating Scale, both for positive affect (-0.5 points; 95% CI, -0.10 to -1.00) and negative affect (0.8 points; 95% CI, 0.20-1.44). Melatonin also increased withdrawn behavior by 1.02 points (95% CI, 0.18-1.86) on the Multi Observational Scale for Elderly Subjects scale, although this effect was not seen if given in combination with light. Combined treatment also attenuated aggressive behavior by 3.9 points (95% CI, 0.88-6.92) on the Cohen-Mansfield Agitation Index or 9%, increased sleep efficiency by 3.5% (95% CI, 0.8%-6.1%), and improved nocturnal restlessness by 1.00 minute per hour each year (95% CI, 0.26-1.78) or 9% (treatment x time effect). CONCLUSIONS Light has a modest benefit in improving some cognitive and noncognitive symptoms of dementia. To counteract the adverse effect of melatonin on mood, it is recommended only in combination with light. TRIAL REGISTRATION controlled-trials.com/isrctn Identifier: ISRCTN93133646.

Genome-wide association for major depressive disorder: a possible role for the presynaptic protein piccolo

Major depressive disorder (MDD) is a common complex trait with enormous public health significance. As part of the Genetic Association Information Network initiative of the US Foundation for the National Institutes of Health, we conducted a genome-wide association study of 435 291 single nucleotide polymorphisms (SNPs) genotyped in 1738 MDD cases and 1802 controls selected to be at low liability for MDD. Of the top 200, 11 signals localized to a 167 kb region overlapping the gene piccolo (PCLO, whose protein product localizes to the cytomatrix of the presynaptic active zone and is important in monoaminergic neurotransmission in the brain) with P-values of 7.7 × 10−7 for rs2715148 and 1.2 × 10−6 for rs2522833. We undertook replication of SNPs in this region in five independent samples (6079 MDD independent cases and 5893 controls) but no SNP exceeded the replication significance threshold when all replication samples were analyzed together. However, there was heterogeneity in the replication samples, and secondary analysis of the original sample with the sample of greatest similarity yielded P=6.4 × 10−8 for the nonsynonymous SNP rs2522833 that gives rise to a serine to alanine substitution near a C2 calcium-binding domain of the PCLO protein. With the integrated replication effort, we present a specific hypothesis for further studies.

Depression Is Associated With Decreased 25-Hydroxyvitamin D and Increased Parathyroid Hormone Levels in Older Adults

CONTEXT Depression has incidentally been related to altered levels of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH), but this relation has never been studied systematically. OBJECTIVE To determine in a large population-based cohort whether there is an association between depression and altered 25(OH)D and PTH levels. DESIGN Population-based cohort study (Longitudinal Aging Study Amsterdam). PARTICIPANTS One thousand two hundred eighty-two community residents aged 65 to 95 years. SETTING The Netherlands. MAIN OUTCOME MEASURE Depression was measured using self-reports (Center for Epidemiologic Studies-Depression scale) and diagnostic interviews (Diagnostic Interview Schedule). Levels of 25(OH)D and PTH were assessed. Potentially confounding factors (ie, age, sex, smoking status, body mass index, number of chronic conditions, and serum creatinine concentration) and explanatory factors (ie, season of data acquisition, level of urbanization, and physical activity) were also measured. RESULTS Levels of 25(OH)D were 14% lower in 169 persons with minor depression and 14% lower in 26 persons with major depressive disorder compared with levels in 1087 control individuals (P < .001). Levels of PTH were 5% and 33% higher, respectively (P = .003). Depression severity (Center for Epidemiologic Studies Depression Scale) was significantly associated with decreased serum 25(OH)D levels (P = .03) and increased serum PTH levels (P = .008). CONCLUSION The results of this large population-based study show an association of depression status and severity with decreased serum 25(OH)D levels and increased serum PTH levels in older individuals.

Association between major depressive disorder and heart rate variability in the Netherlands Study of Depression and Anxiety (NESDA).

CONTEXT It has been hypothesized that depression is associated with lower heart rate variability and decreased cardiac vagal control. This may play an important role in the risk of cardiovascular disease among depressed individuals. OBJECTIVE To determine whether heart rate variability was lower in depressed individuals than in healthy controls in a large adult sample. DESIGN Cross-sectional analyses from a large depression cohort study. SETTING The Netherlands Study of Depression and Anxiety. PARTICIPANTS Two thousand three hundred seventy-three individuals (mean age, 41.8 years; 66.8% female) who participated in the Netherlands Study of Depression and Anxiety. Included were 524 controls, 774 individuals with a diagnosis of major depressive disorder (MDD) earlier in life (remitted MDD), and 1075 individuals with current MDD based on the Composite International Diagnostic Interview. This sample was sufficiently powered to examine the confounding effects of lifestyle, comorbid anxiety, and antidepressants. MAIN OUTCOME MEASURES The standard deviation of normal-to-normal beats (SDNN) and cardiac vagal control, as indexed by respiratory sinus arrhythmia (RSA), were measured during 1(1/2) hours of ambulatory recording of electrocardiograms and thorax impedance. Multivariate analyses were conducted to compare SDNN and RSA across depression groups after adjustment for demographics, health, lifestyle, comorbid anxiety, and psychoactive medication. RESULTS Individuals with remitted and current MDD had a lower mean SDNN and RSA compared with controls (SDNN, 3.1-5.7 milliseconds shorter, P < or = .02; RSA, 5.1-7.1 milliseconds shorter, P < .001; effect size, 0.125-0.269). Comorbid anxiety and lifestyle did not reduce these associations. However, accounting for psychoactive medication removed the association with SDNN and strongly attenuated the association with RSA. Depressed individuals who were using selective serotonin reuptake inhibitors, tricyclic antidepressants, or other antidepressants had significantly shorter SDNNs and RSAs (effect size, 0.207-0.862) compared with controls and depressed individuals not taking medication. CONCLUSIONS This study shows that depression is associated with significantly lowered heart rate variability. However, this association appears to be mainly driven by the effect of antidepressants.

Hippocampal Apoptosis in Major Depression Is a Minor Event and Absent from Subareas at Risk for Glucocorticoid Overexposure

Glucocorticoid (GC) overexposure in animals has been implicated in hippocampal dysfunctioning and neuronal loss. In major depression, hypercortisolemia, hypothalamic-pituitary-adrenocortical-axis alterations, and reduced hippocampal volumes are commonly observed; hence, hippocampal neurodegeneration is also expected. To study possible GC-related pathology, we investigated hippocampal tissue of 15 major-depressed patients, 16 matched controls, and 9 steroid-treated patients, using in situ-end-labeling for DNA fragmentation and apoptosis, and heat-shock protein 70 and nuclear transcription factor kappaB immunocytochemistry for damage-related responses. No obvious massive cell loss was observed in any group. In 11 of 15 depressed patients, rare, but convincing apoptosis was found in entorhinal cortex, subiculum, dentate gyrus, CA1, and CA4. Also in three steroid-treated patients, apoptosis was found. Except for several steroid-treated patients, heat-shock protein 70 staining was generally absent, nor was nuclear transcription factor-kappaB activation found. The detection in 11 of 15 depressed patients, in three steroid-treated, and in one control patient, demonstrates for the first time that apoptosis is involved in steroid-related changes in the human hippocampus. However, in absence of major pyramidal loss, its rare occurrence, that notably was absent from areas at risk for GC damage such as CA3, indicates that apoptosis probably only contributes to a minor extent to the volume changes in depression.

Poor replication of candidate genes for major depressive disorder using genome-wide association data.

Data from the Genetic Association Information Network (GAIN) genome-wide association study (GWAS) in major depressive disorder (MDD) were used to explore previously reported candidate gene and single-nucleotide polymorphism (SNP) associations in MDD. A systematic literature search of candidate genes associated with MDD in case–control studies was performed before the results of the GAIN MDD study became available. Measured and imputed candidate SNPs and genes were tested in the GAIN MDD study encompassing 1738 cases and 1802 controls. Imputation was used to increase the number of SNPs from the GWAS and to improve coverage of SNPs in the candidate genes selected. Tests were carried out for individual SNPs and the entire gene using different statistical approaches, with permutation analysis as the final arbiter. In all, 78 papers reporting on 57 genes were identified, from which 92 SNPs could be mapped. In the GAIN MDD study, two SNPs were associated with MDD: C5orf20 (rs12520799; P=0.038; odds ratio (OR) AT=1.10, 95% CI 0.95–1.29; OR TT=1.21, 95% confidence interval (CI) 1.01–1.47) and NPY (rs16139; P=0.034; OR C allele=0.73, 95% CI 0.55–0.97), constituting a direct replication of previously identified SNPs. At the gene level, TNF (rs76917; OR T=1.35, 95% CI 1.13–1.63; P=0.0034) was identified as the only gene for which the association with MDD remained significant after correction for multiple testing. For SLC6A2 (norepinephrine transporter (NET)) significantly more SNPs (19 out of 100; P=0.039) than expected were associated while accounting for the linkage disequilibrium (LD) structure. Thus, we found support for involvement in MDD for only four genes. However, given the number of candidate SNPs and genes that were tested, even these significant may well be false positives. The poor replication may point to publication bias and false-positive findings in previous candidate gene studies, and may also be related to heterogeneity of the MDD phenotype as well as contextual genetic or environmental factors.

Efficacy of the novel antidepressant agomelatine on the circadian rest-activity cycle and depressive and anxiety symptoms in patients with major depressive disorder: a randomized, double-blind comparison with sertraline.

OBJECTIVE This study evaluates the efficacy of agomelatine, the first antidepressant to be an agonist at MT(1)/MT(2) receptors and an antagonist at 5-HT(2C) receptors, versus sertraline with regard to the amplitude of the circadian rest-activity cycle and depressive and anxiety symptoms in patients with major depressive disorder (MDD). METHOD Outpatients with DSM-IV-TR-defined MDD received either agomelatine 25 to 50 mg (n = 154) or sertraline 50 to 100 mg (n = 159) during a 6-week, randomized, double-blind treatment period. The study was conducted from 2005 to 2006. The main outcome measure was the relative amplitude of the individual rest-activity cycles, expressed as change from baseline to week 6 and collected from continuous records using wrist actigraphy and sleep logs. Secondary outcome measures were sleep efficiency and sleep latency, both derived from actigraphy, and efficacy on depression symptoms (17-Item Hamilton Depression Rating Scale total score and Clinical Global Impressions scale scores) and anxiety symptoms (Hamilton Anxiety Rating Scale total score and subscores). RESULTS A significant difference in favor of agomelatine compared to sertraline on the relative amplitude of the circadian rest-activity cycle was observed at the end of the first week (P = .01). In parallel, a significant improvement of sleep latency (P <.001) and sleep efficiency (P <.001) from week 1 to week 6 was observed with agomelatine as compared to sertraline. Over the 6-week treatment period, depressive symptoms improved significantly more with agomelatine than with sertraline (P <.05), as did anxiety symptoms (P <.05). CONCLUSIONS The favorable effect of agomelatine on the relative amplitude of the circadian rest-activity/sleep-wake cycle in depressed patients at week 1 reflects early improvement in sleep and daytime functioning. Higher efficacy results were observed with agomelatine as compared to sertraline on both depressive and anxiety symptoms over the 6-week treatment period, together with a good tolerability profile. These findings indicate that agomelatine offers promising benefits for MDD patients. TRIAL REGISTRATION www.isrctn.org: ISRCTN49376288.