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.

Serotonin transporter gene polymorphisms: Relation with platelet serotonin level in patients with primary Sjogren's syndrome

Significantly lower platelet serotonin level (PSL) in patients with primary Sjogren's syndrome (pSS) than in healthy controls has been reported in our prior studies. In the present report, we demonstrated effect of functional polymorphisms in the serotonin transporter gene (5-HTT) on PSL. We describe a group of 61 pSS patients and 100 healthy individuals subjects, who received PSL measurement in our prior study. All subjects were genotyped for the promoter 5-HTTLPR (L/S), rs25531 (A/G) and intronic 5-HTTVNTRin2 (l/s) polymorphisms. Overall, the presence of 5-HTTVNTRin2 ss genotype was associated with significantly lower PSL in pSS patients, not in healthy controls. Reduced PSL in pSS patients is in line with hypothesis of association between chronic immunoinflammation and 5-HT system dysregulation, identifying additional mechanisms such as altered 5-HT transport as potential genetic factor contributing to PSL depletion.

Non-steroidal anti-inflammatory drugs and efficacy of antidepressants in major depressive disorder

BACKGROUND

It has been proposed that non-steroidal anti-inflammatory drugs (NSAIDs) may interfere with the efficacy of antidepressants and contribute to treatment resistance in major depressive disorder (MDD). This effect requires replication and a test of whether it is specific to serotonin-reuptake inhibiting (SRI) antidepressants.

METHOD

We tested the effect of concomitant medication with NSAIDs on the efficacy of escitalopram, a SRI antidepressant, and nortriptyline, a tricyclic antidepressant, among 811 subjects with MDD treated for up to 12 weeks in the GENDEP study. Effects of NSAIDs on improvement of depressive symptoms were tested in mixed-effect linear models. Effects on remission were tested in logistic regression. Age, sex, baseline severity and centre of recruitment were considered as potential confounding factors.

RESULTS

Ten percent (n=78) of subjects were taking NSAIDs during the antidepressant treatment. Older subjects were significantly more likely to take NSAIDs. After controlling for age, sex, centre of recruitment and baseline severity, concomitant medication with NSAIDs did not significantly influence the efficacy of escitalopram [β=0.035, 95% confidence interval (CI) -0.145 to 0.215, p=0.704] or nortriptyline (β=0.075, 95% CI -0.131 to 0.281, p=0.476). Although slightly fewer subjects who took NSAIDs reached remission [odds ratio (OR) 0.80, 95% CI 0.49-1.31, p=0.383], this non-significant effect was reversed after controlling for age, sex, baseline severity and recruitment centre effects (OR 1.04, 95% CI 0.61-1.77, p=0.882).

CONCLUSIONS

NSAIDs are unlikely to affect the efficacy of SRI or other antidepressants. Concurrent use of NSAIDs and antidepressants does not need to be avoided.

Depression symptom dimensions as predictors of antidepressant treatment outcome: replicable evidence for interest-activity symptoms

BACKGROUND

Symptom dimensions have not yet been comprehensively tested as predictors of the substantial heterogeneity in outcomes of antidepressant treatment in major depressive disorder.

METHOD

We tested nine symptom dimensions derived from a previously published factor analysis of depression rating scales as predictors of outcome in 811 adults with moderate to severe depression treated with flexibly dosed escitalopram or nortriptyline in Genome-based Therapeutic Drugs for Depression (GENDEP). The effects of symptom dimensions were tested in mixed-effect regression models that controlled for overall initial depression severity, age, sex and recruitment centre. Significant results were tested for replicability in 3637 adult out-patients with non-psychotic major depression treated with citalopram in level I of Sequenced Treatment Alternatives to Relieve Depression (STAR*D).

RESULTS

The interest-activity symptom dimension (reflecting low interest, reduced activity, indecisiveness and lack of enjoyment) at baseline strongly predicted poor treatment outcome in GENDEP, irrespective of overall depression severity, antidepressant type and outcome measure used. The prediction of poor treatment outcome by the interest-activity dimension was robustly replicated in STAR*D, independent of a comprehensive list of baseline covariates.

CONCLUSIONS

Loss of interest, diminished activity and inability to make decisions predict poor outcome of antidepressant treatment even after adjustment for overall depression severity and other clinical covariates. The prominence of such symptoms may require additional treatment strategies and should be accounted for in future investigations of antidepressant response.

Genome-wide association study of increasing suicidal ideation during antidepressant treatment in the GENDEP project

Suicidal thoughts during antidepressant treatment have been the focus of several candidate gene association studies. The aim of the present genome-wide association study was to identify additional genetic variants involved in increasing suicidal ideation during escitalopram and nortriptyline treatment. A total of 706 adult participants of European ancestry, treated for major depression with escitalopram or nortriptyline over 12 weeks in the Genome-Based Therapeutic Drugs for Depression (GENDEP) study were genotyped with Illumina Human 610-Quad Beadchips (Illumina, San Diego, CA, USA). A total of 244 subjects experienced an increase in suicidal ideation during follow-up. The genetic marker most significantly associated with increasing suicidality (8.28 × 10(-7)) was a single-nucleotide polymorphism (SNP; rs11143230) located 30 kb downstream of a gene encoding guanine deaminase (GDA) on chromosome 9q21.13. Two suggestive drug-specific associations within KCNIP4 (Kv channel-interacting protein 4; chromosome 4p15.31) and near ELP3 (elongation protein 3 homolog; chromosome 8p21.1) were found in subjects treated with escitalopram. Suggestive drug by gene interactions for two SNPs near structural variants on chromosome 4q12, one SNP in the apolipoprotein O (APOO) gene on chromosome Xp22.11 and one on chromosome 11q24.3 were found. The most significant association within a set of 33 candidate genes was in the neurotrophic tyrosine kinase receptor type 2 (NTRK2) gene. Finally, we also found trend for an association within genes previously associated with psychiatric phenotypes indirectly linked to suicidal behavior, that is, GRIP1, NXPH1 and ANK3. The results suggest novel pathways involved in increasing suicidal ideation during antidepressant treatment and should help to target treatment to reduce the risk of this dramatic adverse event. Limited power precludes definitive conclusions and replication in larger sample is warranted.

Trajectories of change in depression severity during treatment with antidepressants

BACKGROUND

Response and remission defined by cut-off values on the last observed depression severity score are commonly used as outcome criteria in clinical trials, but ignore the time course of symptomatic change and may lead to inefficient analyses. We explore alternative categorization of outcome by naturally occurring trajectories of symptom change.

METHOD

Growth mixture models were applied to repeated measurements of depression severity in 807 participants with major depression treated for 12 weeks with escitalopram or nortriptyline in the part-randomized Genome-based Therapeutic Drugs for Depression study. Latent trajectory classes were validated as outcomes in drug efficacy comparison and pharmacogenetic analyses.

RESULTS

The final two-piece growth mixture model categorized participants into a majority (75%) following a gradual improvement trajectory and the remainder following a trajectory with rapid initial improvement. The rapid improvement trajectory was over-represented among nortriptyline-treated participants and showed an antidepressant-specific pattern of pharmacogenetic associations. In contrast, conventional response and remission favoured escitalopram and produced chance results in pharmacogenetic analyses. Controlling for drop-out reduced drug differences on response and remission but did not affect latent trajectory results.

CONCLUSIONS

Latent trajectory mixture models capture heterogeneity in the development of clinical response after the initiation of antidepressants and provide an outcome that is distinct from traditional endpoint measures. It differentiates between antidepressants with different modes of action and is robust against bias due to differential discontinuation.

Measuring depression: comparison and integration of three scales in the GENDEP study

BACKGROUND

A number of scales are used to estimate the severity of depression. However, differences between self-report and clinician rating, multi-dimensionality and different weighting of individual symptoms in summed scores may affect the validity of measurement. In this study we examined and integrated the psychometric properties of three commonly used rating scales.

METHOD

The 17-item Hamilton Depression Rating Scale (HAMD-17), the Montgomery-Asberg Depression Rating Scale (MADRS) and the Beck Depression Inventory (BDI) were administered to 660 adult patients with unipolar depression in a multi-centre pharmacogenetic study. Item response theory (IRT) and factor analysis were used to evaluate their psychometric properties and estimate true depression severity, as well as to group items and derive factor scores.

RESULTS

The MADRS and the BDI provide internally consistent but mutually distinct estimates of depression severity. The HAMD-17 is not internally consistent and contains several items less suitable for out-patients. Factor analyses indicated a dominant depression factor. A model comprising three dimensions, namely 'observed mood and anxiety', 'cognitive' and 'neurovegetative', provided a more detailed description of depression severity.

CONCLUSIONS

The MADRS and the BDI can be recommended as complementary measures of depression severity. The three factor scores are proposed for external validation.

Privatization in the health care system of Croatia: effects on general practice accessibility

This paper analyzes some effects of the privatization process in primary health care in Croatia, and in particular evaluates actions taken by providers to improve their accessibility for patients. The sample was stratified by regional density of practices and the status of practices in relation to privatization. Three groups of general practices were included in the study and were assessed twice (in 1997/1998 and 1999/2000): (1) 106 privatized before the beginning of the study; (2) 96 privatized during the study period and (3) 65 that were not yet privatized. The research was performed by structured interview with general practitioners as informants. The indicators analyzed were: possibilities of obtaining first and follow-up visit appointments, honouring scheduled appointments, scheduling visits by telephone, visiting the practitioner after hours and obtaining telephone advice after working hours. Number of registered patients in the practice and perception of patients' waiting times were also assessed. Privatized practices performed better in improving the accessibility of their services for patients: they increasingly offered the possibility for first and follow-up appointments at precise times, scheduled visits by telephone and provided telephone advice outside working hours. They showed greater intention to honour made appointments in order to lower their patients' waiting times. The study indicates that, in the initial stage of privatization, practitioners tend to extend accessibility by structural improvements that are not time consuming. It seems that providers adjust the level of offered accessibility benefits according to the intensity of market competitiveness. Further research is needed to precisely delineate the range of structural adjustments that could be expected by privatization and to verify the effect of observed changes on the quality of care and health outcomes.

Catatonic schizophrenia has a shorter pre-hospitalisation interval than other types of schizophrenia

The time elapsed between the first onset of symptoms and the onset of first hospitalisation was analysed in 355 participants diagnosed with paranoid, simple, hebephrenic and catatonic schizophrenia and shizoaffective disorder. The real onset of the disease was assessed from interviews with reliable relatives and by reviewing medical records in general practices and out-patient psychiatric services. In 184 patients a family history of schizophrenia was identified. A positive family history was found to significantly increase the interval preceding first hospitalisation in all analysed types, except in catatonic schizophrenia. Possible reasons causing this prolongation are discussed, as well as repercussions of the results to studies using age of first hospitalisation as the leading indicator.

Stressor characteristics and post-traumatic stress disorder symptom dimensions in war victims

AIM

To evaluate how the type of trauma is related to specific symptom patterns in patients with post-traumatic stress disorder (PTSD) according to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria.

METHODS

A total of 136 PTSD patients exposed to war-related traumatic experiences were divided in four groups: 79 veterans, 18 former prisoners (who witnessed or were subject to torture or frequent assaults), 15 victims of rape, and 24 refugees from Bosnia and Herzegovina. Each group was homogenous in regard to traumatic experiences.

RESULTS

Significant inter-group differences were found in symptoms listed in the DSM-IV criteria, and under criteria C (avoidance) and D (arousal). No such differences were observed in symptoms listed under criterion B (intrusive symptoms). The results indicate that stressor characteristics may play a role not only in the variety of symptoms exhibited, but particularly in the number of avoidance and arousal symptoms. Victims of rape tended to present with more avoidance symptoms and fewer hyperarousal symptoms, whereas former prisoners and veterans tended to report more hyperarousal symptoms. Rape victims and former prisoners also reported more symptoms than the other groups.

CONCLUSION

There is a strong indication that stressor characteristics influence the variety and number of exhibited intrusive, avoidance, and arousal symptoms. More research is needed to precisely define individual symptom dimensions possibly relating to particular stressor characteristics. Additional studies are needed to determine whether PTSD, as it is currently defined in the DSM-IV, is really a homogenous diagnostic category.

War victims in need of physical rehabilitation in Croatia

A Rehabilitation Information System was created in July 1993 in order to register war victims in need of physical rehabilitation all over Croatia. The system is currently operating and presented data covers the period from July 1991 to July 1995. Approximately 15,000 questionnaires had been completed and returned from medical institutions on in total 8589 disabled war victims in need of rehabilitation. People with severe disabilities comprised about 20% of all in need of rehabilitation. Those reported injured were 3.5 times more than those in need of physical rehabilitation. Most common types of injuries were fractures with a permanent disabling condition (3109 persons), peripheral nerve injuries (1213 persons) and amputations (956 persons). Traumatic brain injuries were registered for 594 and spinal cord injuries for 262 persons. Causes of injuries were explosive devices (such as mines, mortar shell shrapnel, etc.) in 37% of cases, bullets in 22%, accidents in 7%, other (such as fire, blast injuries, etc.) and unknown causes in 34%.

Identification of war victims in Croatia

The intention of this paper is to describe the organizational principles and indicate the results already achieved in the identification of war victims in Croatia. By 25 February 1993, 6,493 victims had been identified. A model is proposed that could be used in the course of identification processes, examining the methods and principles of identification which have been complicated by the time interval of more than a year from the time of death, for a presumed number of several thousand (up to 14,000) unidentified victims, possibly in mass graves. Identification is further complicated by the lack of ante-mortem medical and dental records and the incapacity to utilize more expensive methods of identification. Attention is drawn to a group of more complex cases examined at the Institute of Forensic Medicine and Criminology.