Mental health, psychological distress and burnout in Australian dental practitioners

BACKGROUND

Dental practitioners are known to experience a high level of stress, but little is known about the mental health of Australian dental practitioners. The aim of this study was to investigate the prevalence of mental health conditions among Australian dental practitioners.

METHODS

A cross sectional survey of 1483 Australian dental practitioners was carried out from October to December 2021. Participants reported aspects of mental health including depression, anxiety disorder, burnout (Sydney Burnout Measure) and psychological distress (Kessler Psychological Distress Scale and General Health Questionnaire 12).

RESULTS

Self-reported psychological distress was high, with 32.0% rated as having moderate or severe psychological distress and 59.4% a high likelihood of minor (or more severe) psychological distress. One in four participants (24.8%) were classified as likely to be experiencing burnout, with 25.9% reporting ever having a diagnosis of depression, 11.4% a current diagnosis of depression, 23.1% ever having a diagnosis of anxiety disorder and 12.9% a current diagnosis of anxiety disorder.

CONCLUSION

Australian dental practitioners reported a high burden of psychological distress, burnout and mental health issues, suggesting a need for education and programmes to support their mental health and wellbeing. © 2023 Australian Dental Association.

Australian dental practitioners experience of burnout

BACKGROUND

The aim of this study was to investigate factors associated with burnout in Australian dental practitioners.

METHODS

A cross-sectional survey of 1483 Australian dental practitioners was conducted from Oct to Dec 2021. Participants reported burnout using the Sydney Burnout Measure, and aspects of mental health including psychological distress, depression, and anxiety disorders. Predictors of burnout were explored using a generalized linear model with a stepped approach including demographic, health and risk factor variables.

RESULTS

One in four participants were classified as likely to be experiencing burnout. Burnout was associated with working in a regional/rural location (β = 2.82, p < 0.001), an academic/non-clinical role (β = 5.01, p = 0.037), more years of experience as a dental practitioner (β = 0.08, p = 0.022), a current diagnosis of depression (β = 2.38, p = 0.049), moderate/severe psychological distress (β = 7.16, p < 0.001), poor self-rated physical health (β = 5.84, p < 0.001) and increasing alcohol consumption (β = 0.17, p = 0.020). Participants who scored high on resilience (β = -0.23, p = 0.002) or perfectionism (β = -0.24, p < 0.001) had lower burnout scores.

CONCLUSION

Australian dental practitioners appear to be at high risk of burnout which may impact on their health and wellbeing and ability to deliver patient care. There is a need for support services to manage burnout and education to address workplace and environmental factors that may contribute to burnout.

875 Use of Oriented Priors Through Magnetic Tractography (MAGNET) In Deliniation Of Meyer's Loop and Correlation with Visual Field Deficit In Temporal Lobe Epilepsy (TLE) Surgery: A Pilot Study

Introduction

Pre-operative white matter tract reconstruction of the Meyer’s loop (ML) of the optic radiation using diffusion MRI (tractography) can be used to prevent post-operative visual-field deficit. Due to its complex anatomy, precise reconstruction of the ML is challenging and often underestimated. Previous work has suggested that an innovative tractography technique using oriented priors called MAGNET better approximates reconstruction to reported histological prosections. This proof-of-context study validates the MAGNET methodology in predicting visual-field deficits in patients undergoing TLE surgery.

Method

Diffusion MRI datasets were used to reconstruct pre-operative ML using MAGNET in five patients. These were overlaid on post-operative T2-MRI series demonstrating the surgically resected area to measure overlap between resection and reconstructed ML. A correlation with post-operative visual-field defects was established.

Results

There was no evidence of visual field deficit in the cases where there was no overlap between the reconstructed ML and the resected region. In the cases with overlap with reconstructed ML and resection, there was visual deficit found. There was no correlation between proportion of resected ML and visual deficit.

Conclusions

This pilot demonstrates that MAGNET accurately reconstructs ML in pre-surgical TLE cases compared to standard tractography techniques and can be used to augment neurosurgical planning and resection.

The effect of gradient nonlinearities on fiber orientation estimates from spherical deconvolution of diffusion magnetic resonance imaging data

Gradient nonlinearities in magnetic resonance imaging (MRI) cause spatially varying mismatches between the imposed and the effective gradients and can cause significant biases in rotationally invariant diffusion MRI measures derived from, for example, diffusion tensor imaging. The estimation of the orientational organization of fibrous tissue, which is nowadays frequently performed with spherical deconvolution techniques ideally using higher diffusion weightings, can likewise be biased by gradient nonlinearities. We explore the sensitivity of two established spherical deconvolution approaches to gradient nonlinearities, namely constrained spherical deconvolution (CSD) and damped Richardson-Lucy (dRL). Additionally, we propose an extension of dRL to take into account gradient imperfections, without the need of data interpolation. Simulations show that using the effective b-matrix can improve dRL fiber orientation estimation and reduces angular deviations, while CSD can be more robust to gradient nonlinearity depending on the implementation. Angular errors depend on a complex interplay of many factors, including the direction and magnitude of gradient deviations, underlying microstructure, SNR, anisotropy of the effective response function, and diffusion weighting. Notably, angular deviations can also be observed at lower b-values in contrast to the perhaps common assumption that only high b-value data are affected. In in vivo Human Connectome Project data and acquisitions from an ultrastrong gradient (300 mT/m) scanner, angular differences are observed between applying and not applying the effective gradients in dRL estimation. As even small angular differences can lead to error propagation during tractography and as such impact connectivity analyses, incorporating gradient deviations into the estimation of fiber orientations should make such analyses more reliable.

Acoustic shock: an update review

BACKGROUND

This paper discusses the concept of acoustic shock based on a literature review and the results of our own research into cases seen in both clinical and medicolegal practice. With the demise of traditional 'metal bashing' and 'smoke stack' heavy industries, there has been a decline in the incidence of noise-induced hearing loss and tinnitus in this form of employment. However, with the increasing establishment of call centre work, the emergence of acoustic shock has been noted. Acoustic shock is recognised as a clinical entity distinct from noise-induced hearing loss and acoustic trauma.

OBJECTIVE

This article discusses clinical implications, medicolegal considerations in light of a recent high-profile court case and proposed criteria for diagnosis.

Refined diagnostic criteria for the bipolar disorders: phase two of the AREDOC project

OBJECTIVE

As limitations exist across DSM criteria sets for defining and differentiating the bipolar disorders generally and their component bipolar I (BP-1) and bipolar II (BP-II) sub-types, we sought to generate empirically based criteria.

METHOD

We formed an international Task Force (TF) comprising members with bipolar disorder expertise, and who recruited 74 patients with a TF-diagnosed bipolar I and 104 with a bipolar II condition (with patients responding to definitional queries and symptom questionnaires), while 33 unipolar depressed patients recruited by the first author also completed the symptom questionnaire. A factor analysis sought to determine granular hypo/manic constructs.

RESULTS

The bipolar disorder subjects strongly affirmed a new general definition of a bipolar disorder (capturing both manic and hypomanic episodes). While DSM-5 requires impaired functioning, we established that a high percentage of individuals with a BP-I or a BP-II disorder reported improved functioning and therefore modified this criterion. Analyses identified syptoms with differential high rates in individuals with bipolar disorder and its sub-types (and thus not simply capturing happiness), while a factor analysis generated seven symptom constructs both linked with and differing from DSM-5 bipolar symptom criteria.

CONCLUSION

This second-stage report details a new set of criteria for differentiating the bipolar disorders from unipolar depressive conditions, while arguing for BP-I and BP-II disorders being differentiated principally by the respective presence or absence of psychotic features. Future studies will evaluate whether further modifications are required and examine for differential treatment benefits for those with a BP-I versus a BP-II condition.

Cross-scanner and cross-protocol multi-shell diffusion MRI data harmonization: Algorithms and results

Cross-scanner and cross-protocol variability of diffusion magnetic resonance imaging (dMRI) data are known to be major obstacles in multi-site clinical studies since they limit the ability to aggregate dMRI data and derived measures. Computational algorithms that harmonize the data and minimize such variability are critical to reliably combine datasets acquired from different scanners and/or protocols, thus improving the statistical power and sensitivity of multi-site studies. Different computational approaches have been proposed to harmonize diffusion MRI data or remove scanner-specific differences. To date, these methods have mostly been developed for or evaluated on single b-value diffusion MRI data. In this work, we present the evaluation results of 19 algorithms that are developed to harmonize the cross-scanner and cross-protocol variability of multi-shell diffusion MRI using a benchmark database. The proposed algorithms rely on various signal representation approaches and computational tools, such as rotational invariant spherical harmonics, deep neural networks and hybrid biophysical and statistical approaches. The benchmark database consists of data acquired from the same subjects on two scanners with different maximum gradient strength (80 and 300 ​mT/m) and with two protocols. We evaluated the performance of these algorithms for mapping multi-shell diffusion MRI data across scanners and across protocols using several state-of-the-art imaging measures. The results show that data harmonization algorithms can reduce the cross-scanner and cross-protocol variabilities to a similar level as scan-rescan variability using the same scanner and protocol. In particular, the LinearRISH algorithm based on adaptive linear mapping of rotational invariant spherical harmonics features yields the lowest variability for our data in predicting the fractional anisotropy (FA), mean diffusivity (MD), mean kurtosis (MK) and the rotationally invariant spherical harmonic (RISH) features. But other algorithms, such as DIAMOND, SHResNet, DIQT, CMResNet show further improvement in harmonizing the return-to-origin probability (RTOP). The performance of different approaches provides useful guidelines on data harmonization in future multi-site studies.

Differentiating clinical and non-clinical depression: a heuristic study offering a template for extension studies

OBJECTIVE

To differentiate clinical and non-clinical depression via a set of symptoms.

METHODS

A sample of 140 patients attending a clinical service for those with mood disorders together with 40 subjects denying ever experiencing a clinical episode of depression were compared, with participants completing a questionnaire capturing many symptoms of depression as well as illness correlates.

RESULTS

A latent class analysis of symptom data identified two classes and with class assignment corresponding strongly with initial clinical vs. non-clinical assignment. Univariate analyses identified the extent to which individual symptoms contributed to differentiation. Study data suggested DSM criteria that would benefit from re-writing or of reassignment. Two models for classifying clinical depression were generated. The first involved individuals feeling hopeless and also being suicidal or at risk of self-harm. The second involved a symptom set corresponding to DSM-5 criteria but with only five making significant independent contributions to diagnostic differentiation.

CONCLUSION

The study is heuristic in offering a strategy for more precisely differentiating clinical and non-clinical depression in more representative samples, so allowing resolution of key features, and determining whether a monothetic or polythetic diagnostic symptom criterion model is optimal.

Development of a Scale to Measure Interpersonal Sensitivity

We describe the development of a self-report measure (the Interpersonal Sensitivity Measure or IPSM). The IPSM generates a total score as well as five sub-scale scores: interpersonal awareness, need for approval, separation anxiety, timidity and fragile inner-self. Its reliability is demonstrated by high internal consistency in two separate groups, and by stability in scores over time in a non-clinical group. Studies of a clinical group of depressives showed change in scale scores following improvement in the depressive state, suggesting some sensitivity of the measure to mood state. The IPSM appears related to measures of neuroticism and to low self-esteem but not to a modified concept of neuroticism, emotional arousability. The constructs contributing to interpersonal sensitivity and their relevance to depression are considered. Some preliminary findings of higher scores in depressives compared to non-depressives are reported.

Home-based palliative care

BACKGROUND

While most people say they would prefer to be cared for and to die at home, this outcome is often not achieved. This represents a service gap that general practitioners (GPs) are optimally positioned to fill.

OBJECTIVES

The aim of this paper is to synthesise existing evidence-based frameworks of palliative care together with other resources, to present a cohesive model of care that GPs can easily systematise to guide high-quality home-based palliative care.

DISCUSSION

Key clinical processes include advance care planning and development of medical goals of patient care plans and terminal care plans. Three essential elements for high-quality palliative care incorporated into the model include a compassionate GP, the care team and various practical resources. Palliative care sits well within the GP specialist scope of practice. GPs have at their disposal many resources that effectively and efficiently support them in their palliative care practice.

How to choose an antidepressant medication

OBJECTIVE

We consider how to choose an antidepressant (AD) medication for the treatment of clinical depression.

METHOD

A narrative review was undertaken addressing antidepressant 'choice' considering a range of parameters either weighted by patients and clinicians or suggested in the scientific literature. Findings were synthesised and incorporated with clinical experience into a model to assist AD choice.

RESULTS

Efficacy studies comparing ADs offer indicative guidance, while precision psychiatry prediction based on genetics, developmental trauma, neuroimaging, behavioural and cognitive biomarkers, currently has limited clinical utility. Our model offers guidance for AD choice by assessing first for the presence of a depressive subtype or symptom cluster and matching choice of AD class accordingly. Failing this, an AD can be chosen based on depression severity. Within-class choice can be determined by reference to personality style, patient preference, medical or psychiatric comorbidities and side-effect profile.

CONCLUSION

Clarification of AD choice would occur if medications are trialled in specific depressive subtypes rather than using the generic diagnosis of major depressive disorder (MDD). Such 'top-down' methods could be enhanced by 'bottom-up' studies to classify individuals according to symptom clusters and biomarkers with AD efficacy tested in these categories. Both methods could be utilised for personalised AD choice.

The effect of 1 week of repeated ischaemic leg preconditioning on simulated Keirin cycling performance: a randomised trial

BACKGROUND

Coaches continually seek new ways of doing things and also refine existing techniques to improve sporting performance. Coaches are currently experimenting using ischaemic preconditioning (IPC) over consecutive days in the hope of improving competitive performances.

AIMS

First, to quantify the physiological impact of 1 week of IPC on simulated Keirin cycling performance. Second, to investigate if biochemical stress markers are affected over the treatment period.

METHODS

Using a randomised, sham-controlled design, 18 active adults undertook seven consecutive days of IPC treatment (4×5 min occlusion/reperfusion) applied to each leg at either 220 mm Hg (treatment, n=9) or 20 mm Hg (sham, n=9). Urinary measures of inflammation, oxidative stress and indirect nitric oxide synthesis were undertaken daily. A simulated Keirin cycling competition (4×30 s Wingate tests) was performed on day 10, with baseline and postintervention cycling VO2max (days 1, 11 and 18) and 30 s Wingate tests (day 2) undertaken for comparison.

RESULTS

The treatment group had enhanced mean cycling power (3.4%), while neopterin and biopterin in conjunction with total neopterin were significantly lower (p<0.05) and total biopterin significantly greater (p<0.05) during the simulated Keirin. Aerobic fitness measures significantly improved from baseline to postintervention (VO2peak: 12.8% ↑, maximal aerobic power: 18.5% ↑).

CONCLUSIONS

Seven consecutive days of IPC improved aerobic and anaerobic capacity measures, with modulations in oxidative stress, immune system activation and nitric oxide/catecholamine synthesis.

Targeting and transforming major depression

OBJECTIVE

To detail limitations to the construct of 'major depression', argue for repositioning it as a proxy for 'clinical depression' and then operationalize it and its principal constituent depressive subtypes, while preserving the DSM criteria-based format.

METHOD

We summarize limitations to major depression being viewed as a diagnostic entity. Data from 391 clinically depressed patients were analysed to identify high-prevalence non-specific depressive symptoms to define 'clinical depression' as well as the features showing specificity to a melancholic depressive subtype.

RESULTS

We identified a set of high-prevalence and generalized symptoms for defining clinical depression and with many being current criteria for major depression. We also developed a refined set of melancholic features and with their underlying distributions generating two classes that correlated strongly with clinical diagnoses of a melancholic or non-melancholic depression, thus validating its capacity to so differentiate. We append criteria sets for diagnosing clinical depression and its principal diagnostic subtypes (psychotic, melancholic and non-melancholic).

CONCLUSION

This heuristic study reframes and modifies major depression's criteria set to define a domain of clinical depression with additional criteria and then allowing the delineation of three diagnostic subtypes. If this paradigm shift is accepted and further refined, greater precision in diagnosis, treatment and research would be anticipated.

Multimodal Brain Imaging Reveals Structural Differences in Alzheimer's Disease Polygenic Risk Carriers: A Study in Healthy Young Adults

BACKGROUND

Recent genome-wide association studies have identified genetic loci that jointly make a considerable contribution to risk of developing Alzheimer's disease (AD). Because neuropathological features of AD can be present several decades before disease onset, we investigated whether effects of polygenic risk are detectable by neuroimaging in young adults. We hypothesized that higher polygenic risk scores (PRSs) for AD would be associated with reduced volume of the hippocampus and other limbic and paralimbic areas. We further hypothesized that AD PRSs would affect the microstructure of fiber tracts connecting the hippocampus with other brain areas.

METHODS

We analyzed the association between AD PRSs and brain imaging parameters using T1-weighted structural (n = 272) and diffusion-weighted scans (n = 197).

RESULTS

We found a significant association between AD PRSs and left hippocampal volume, with higher risk associated with lower left hippocampal volume (p = .001). This effect remained when the APOE gene was excluded (p = .031), suggesting that the relationship between hippocampal volume and AD is the result of multiple genetic factors and not exclusively variability in the APOE gene. The diffusion tensor imaging analysis revealed that fractional anisotropy of the right cingulum was inversely correlated with AD PRSs (p = .009). We thus show that polygenic effects of AD risk variants on brain structure can already be detected in young adults.

CONCLUSIONS

This finding paves the way for further investigation of the effects of AD risk variants and may become useful for efforts to combine genotypic and phenotypic data for risk prediction and to enrich future prevention trials of AD.

Geophysical Variables and Behavior: Xcix. Reductions in Numbers of Neurons within the Parasolitary Nucleus in Rats Exposed Perinatally to a Magnetic Pattern Designed to Imitate Geomagnetic Continuous Pulsations: Implications for Sudden Infant Death

Correlational analyses have shown a moderate strength association between the occurrence of continuous pulsations, a type of geomagnetic activity within the 0.2-Hz to 5-Hz range, and the occurrence of Sudden Infant Deaths. In the present study, rats were exposed continuously from two days before birth to seven days after birth to 0.5-Hz pulsed-square wave magnetic fields whose intensities were within either the nanoTesla or microTesla range. The magnetic fields were generated in either an east-west (E-W) or north-south (N-S) direction. At 21 days of age, the area of the parasolitary nucleus (but not the solitary nucleus) was significantly smaller, and the numbers of neurons were significantly less in rats that had been exposed to the nanoT fields generated in the east-west direction or to the microTesla fields generated within either E-W or N-S direction relative to those exposed to the N-S nanoTesla fields. These results suggest nanoTesla magnetic fields, when applied in a specific direction, might interact with the local geomagnetic field to affect cell migration in structures within the brain stem that modulate vestibular-related arousal and respiratory or cardiovascular stability.

The impact of climate on risk of mania

Introduction

Bipolar disorder varies with season: admissions for depression peak in winter and mania peak in summer. Sunlight presumably increases the risk of mania through suppression of melatonin. If so, we expect admissions for mania to vary in accordance with climate variations.

Objectives

To investigate how climate and climate changes affects admissions for mania.

Aims

To identify which climate variables – sunshine, ultraviolet radiation, rain and snow cover – affect admissions for mania.

To examine whether year-to-year weather variation as well as long-term climate changes reflects the variation in number of admissions for mania.

Methods

This register-based nationwide cohort study covers all patients admitted for mania (ICD-10 code F31 or F30.0–F30.2) between 1995 and 2012 in Denmark. Climate data, obtained from the Danish Meteorological Institute, were merged with admission data and correlated using an Unobserved Component Model regression model.

Preliminary results

In total, 8893 patients were admitted 24,313 times between 1995 and 2012: 6573 first-admissions and 17,740 readmissions. Linear regression shows significant association between admissions per day and hours of sunshine (P < 0.01) and ultraviolet radiation (UV) dose (P < 0.01). Average days with snow cover and rain were not significantly correlated with admissions. Analyses on year-to-year variation and long-term change are not yet available.

Preliminary conclusions

Admissions for mania are correlated with sunshine and UV, but not rain and snow cover. If more patients are admitted during very sunny summers compared with less sunny summers this implies a relation with light itself and not just season.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Quantification of sodium pentobarbital residues from equine mortality compost piles

Sodium pentobarbital, a euthanasia drug, can persist in animal carcasses following euthanasia and can cause secondary toxicosis to animals that consume the remains. This experiment was conducted to observe the effects of composting on euthanized horse carcass degradation and sodium pentobarbital residues in compost material up to 367 d. Six separate compost bins were constructed on pastureland. Three bins served as the control while 3 served as the treatment. The carbonaceous material, or bulking agent, consisted of hardwood chips mixed with yard waste wetted to approximately 50% moisture content. Bulking agent was added to each bin at a depth of 0.46 m, creating the pad. A licensed veterinarian provided 6 horse carcasses for use in the experiment. These horses had required euthanasia for health reasons. All horses were weighed and then sedated with an intravenous injection of 8 mL of xylazine. After sedation the 3 horses in the treatment group were euthanized by intravenous injection of 60 mL of sodium pentobarbital. The 3 control group horses were anesthetized by intravenous injection of 15 mL of ketamine hydrochloride and then humanely euthanized by precise gunshot to the temporal lobe. Following euthanasia, each carcass was placed on the center of the pad and surrounded with 0.6 m of additional bulking agent. Serum and liver samples were obtained immediately following death. Compost samples were obtained on d 7, 14, 28, 56, 84, 129, 233, and 367 while soil samples were obtained on d -1 and 367. Each sample was analyzed for sodium pentobarbital concentration. Compost pile and ambient temperatures were also recorded. Composting successfully degraded soft tissue with only large bones remaining. Data illustrate that sodium pentobarbital was detectable up to 367 d in compost piles with no clear trend of concentration reduction. Drug residues were detected in soil samples indicating that sodium pentobarbital leached from the carcass and through the pad. These findings confirm the persistence of sodium pentobarbital from equine mortality compost piles and emphasize the importance of proper carcass management of animals euthanized with a barbiturate to reduce environmental impact and secondary toxicosis.

The 'disconnect' between initial judgments of lamotrigine vs. its real-world effectiveness in managing bipolar disorder. A tale with wider ramifications

OBJECTIVE

To detail the disconnect between the quantified efficacy of the mood stabilizer lamotrigine in its registration controlled trials and its later judged clinical effectiveness and consider some determinants of disconnects between some efficacy trial findings and 'real-world' clinical effectiveness judgments.

METHOD

Published articles considering lamotrigine as a treatment for the bipolar I or II disorders were selected for review. While randomized controlled trials were weighted, we also consider open trials and effectiveness observations from clinician researchers and demonstrate that lamotrigine has been quite variably judged over time.

RESULTS

We suggest that the early trials evaluating lamotrigine for acute bipolar disorder depression focused on a suboptimal clinical target, and in so doing, ensured less lamotrigine efficacy compared with trials of bipolar disorder preventative treatment. Moreover, a number of additional methodological limitations compromised analyses. We also detail variable reporting of actual study results. The initial sharp disconnect (between efficacy and effectiveness judgments) has narrowed as lamotrigine has been evaluated and progressively taken up as a maintenance mood stabilizer.

CONCLUSION

The lamotrigine disconnect story provides a number of salutary lessons that are salient to evaluating the effectiveness and ecological niche of any psychotropic medication. The lamotrigine story presented here argues strongly for the wisdom of encouraging an iterative process between efficacy studies and clinical observation.

The utility of a classificatory decision tree approach to assist clinical differentiation of melancholic and non-melancholic depression

BACKGROUND

Studies suggest that differentiating melancholic from non-melancholic depressive disorders is advanced by use of illness course as well as symptom variables but, in practice, potentially differentiating variables are generally positioned as having equal value. Judging that differentiating features are more likely to vary in their signal intensity, we sought to determine the number of features required to effect differentiation and their hierarchical order.

METHODS

The 24-item clinician-rated Sydney Melancholia Prototype Index (SMPI-CR) was completed for 364 unipolar depressed patients. The sample was divided into two cohorts according to the recruitment period. An RPART classification tree analysis identified the most discriminating SMPI items in the development sample of 197 patients, and examined the sensitivity and specificity of the diagnostic decisions, then sought to replicate findings in a validation sample of 169 patients.

RESULTS

Independent analyses of putative SMPI items identified only seven items as required to discriminate those with clinically-diagnosed melancholic or non-melancholic depression when the conditions were examined separately. An RPART analysis considering differentiation of melancholic and non-melancholic depression in the total samples retained five of those items in the classification tree, three of which were non-symptom items, and with 92% sensitivity and 80% specificity in the development sample. This reduced item set showed 93% sensitivity and 82% specificity in the validation sample.

LIMITATIONS

Our clinical judgment of melancholic or non-melancholic depression may not correspond with the clinical logic employed by other clinicians.

CONCLUSION

Only five SMPI items were required to derive a succinct and efficient decision tree, comprising high sensitivity and specificity in differentiating melancholic and non-melancholic depression. Current study findings provide an empirical model that could enrich clinicians׳ approach to differentiating melancholic and non-melancholic depression.

Differentiating 'clinical' and 'non-clinical' depression

OBJECTIVE

There has been increasing concern about extensions to the definition of 'clinical' depression, but little evident investigation as to how clinical and non-clinical depressive states might best be differentiated. This review considers the potential of many candidate symptom and non-symptom parameters.

METHOD

We overview representative concerns and theories about the nature of psychiatric disorders before reviewing the potential utility of candidate parameters for differentiating clinical and non-clinical depressive states.

RESULTS

While we detail limitations to all candidate parameters designed to distinguish between clinical and non-clinical depression, their actual utility may only be able to be judged by empirical testing across appropriate comparison groups.

CONCLUSION

We argue for initial comparisons being made between prototypically defined categorical (i.e. psychotic, melancholic and bipolar) depressive disease states and residual non-melancholic clinical depressive states, before considering how each of those two clinical subsets might differ from non-clinical depressive mood states.

Cleaving depressive diseases from depressive disorders and non-clinical states

OBJECTIVE

We sought to determine whether putative depressive diseases could be differentiated categorically from clinical depressive disorders and non-clinical mood states.

METHOD

We interviewed volunteers who reported or denied any lifetime depressive mood state and analyzed data from the former group reporting on their 'most severe' depressive episode. We employed latent class analysis (LCA) to determine whether a two-class solution was supported and the contribution of individual variables to class allocations.

RESULTS

All variables were significant predictors of class allocation. LCA-assigned Class I participants reported more depressive symptoms, had more distressing episodes and more lasting consequences, were more likely to view their depression as 'like a disease', and as being both disproportionately more severe and persistent in relation to any antecedent stressor. Validation involved comparison of LCA assignment with DSM-IV diagnosis for their most severe depressive episode. Of those assigned to Class I, 89% had a DSM diagnosis of melancholic, psychotic or bipolar depression. Class II had all those failing to meet criteria for a depressive episode and the majority of those with a non-melancholic depressive condition.

CONCLUSION

Despite not including individual depressive symptoms, study variables strongly differentiated putative depressive diseases from a composite of clinical depressive conditions and subclinical depressive states.

Is essential fatty acid status in late pregnancy predictive of post-natal depression?

OBJECTIVE

We tested the hypothesis that abnormal levels of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) during late pregnancy are associated with antenatal and post-natal depression.

METHOD

We interviewed a sample of more than 900 women in late pregnancy. We assessed whether they met criteria for depression on a standardized measure of post-natal depression [the Edinburgh Post-natal Depression Scale (EPDS)] and met DSM-IV criteria for major depression and/or were in receipt of antidepressant medication. Blood was collected at that time to generate data on nine PUFA variables. Sample members were re-interviewed post-natally to determine depressive experience in the 3 months following the birth of their baby.

RESULTS

Univariate associations were demonstrated between pre-natal depression categorized using DSM criteria and measures of blood fatty acids including total omega-3, the ratio of omega-6 to omega-3, docosahexaenoic acid (DHA) omega-3 and DHA plus eicosapentaenoic acid (EPA) omega-3. Such associations were not found post-natally, but different associations were quantified between EPDS-diagnosed depression and total omega-6, total omega-3 and EPA omega-3. In multivariate analyses, slight associations were maintained between EPDS and lower omega-3, lower EPA and higher omega-6 when neuroticism, stress during pregnancy, a lifetime episode of depression and older age were included in the analysis.

CONCLUSION

Findings in such a large sample indicate that PUFA status in late pregnancy is only slightly linked with the risk of post-natal depression when depression was quantified by the EPDS. There were no associations between post-natal depression diagnosed by DSM criteria and any fatty acid variables.

Computational hemodynamics analysis of intracranial aneurysms treated with flow diverters: correlation with clinical outcomes

BACKGROUND AND PURPOSE

Recent studies have shown promising results regarding intracranial aneurysms treated with flow diverters. However, these have had adverse effects, including delayed aneurysm occlusion, posttreatment symptoms, and rupture. The hemodynamic profiles of aneurysms treated with flow diverters were analyzed to determine the ones associated with successful and failed treatments.

MATERIALS AND METHODS

Patient-specific computational fluid dynamics were used to simulate hemodynamic profiles, including the presence of jet flow, energy loss, volume flow, and wall shear stress in 4 successful occlusions of aneurysms and 4 failed cases after flow-diverter deployment. In these 4 failed cases, hemodynamic profiles were examined again after a hypothetic second intervention. This involved replacing the failed flow diverter with a hypothetic optimally deployed flow diverter or simulated placement of a second flow diverter within the first (double hypothetic optimally deployed).

RESULTS

Where successful occlusions were achieved, a marked obliteration of jet flow was observed. Flow entering the aneurysm sac was diverted via the center of the flow diverter and joined smoothly with the continuation of flow leaving the aneurysm sac into the parent arteries. These observations were supplemented by a reduction in the other hemodynamic profiles. Aneurysm neck geometry might influence the efficacy of the flow diverter.

CONCLUSIONS

Hemodynamic indices, as calculated by using computational fluid dynamics techniques, have close correlation with flow-diverter treatment outcome. Computational fluid dynamics could be potentially useful as a planning tool for neurointerventionists by simulating an optimized flow-diverter deployment strategy before the procedure and evaluating posttreatment outcome.

The superiority of antidepressant medication to cognitive behavior therapy in melancholic depressed patients: a 12-week single-blind randomized study

OBJECTIVE

To pursue the previously long-standing but formally untested clinical view that melancholia is preferentially responsive to antidepressant medication in comparison with psychotherapy [specifically Cognitive Behavior Therapy (CBT)]. Second, to determine whether a broader action antidepressant medication sequencing regimen is superior to a Selective Serotonin Reuptake Inhibitor (SSRI) alone.

METHOD

We sought to recruit a large sample of participants with melancholic depression for a 12-week trial but inclusion criteria compromised recruitment and testing the second hypothesis. The first hypothesis was evaluated by comparing 18 participants receiving antidepressant medication to 11 receiving CBT. Primary study measures were the Hamilton Rating Scale for Depression (HAM-D) and the Hamilton Endogenous Subscale (HES), rated blindly, while several secondary measures also evaluated outcome.

RESULTS

Participants receiving medication had a superior 12-week outcome to those receiving CBT, with significant differences present on primary measures as early as 4 weeks. At trial conclusion, the percentage improvement in HAM-D scores was 61.1% vs. 34.4%, respectively [Number Needed to Treat (NNT) = 3.7] and with those in receipt of medication returning non-significantly higher HAM-D responder (66.6% vs. 36.4%, NNT = 2.8) and remission (66.7% vs. 45.4%, NNT = 4.7) rates.

CONCLUSION

As the sample size was small and participants evidenced only moderate levels of depression severity, the study risked being underpowered and idiosyncratic. Despite the small sample, the superiority of antidepressant medication to CBT in those with a melancholic depression was distinctive in this pilot study.

The 'real world' utility of a web-based bipolar disorder screening measure

OBJECTIVE

To determine whether those completing a self-report bipolar self-test measure and identified as having a likely bipolar disorder judged the self-test as useful and had a subsequent superior illness course.

METHOD

We invited those completing the web-based Mood Swings Questionnaire (or MSQ) to provide contact details and contribute to a 3-month study evaluating their responses to being identified as having a likely bipolar disorder, any subsequent action taken and the impact of such actions on their illness trajectory.

RESULTS

We analysed data received from 665 participants screening 'positive' on the MSQ and completing baseline and 3-month follow-up data. High rates of satisfaction with the MSQ were quantified, with respondents viewing the measure as informative, validating and/or motivating. Of those receiving a confirmed bipolar diagnosis, such clarification occurred on average 12 years after their first depressive episode. Most implemented self-management strategies irrespective of whether seeking formal diagnostic clarification or not. Participants improved on depressive, quality of life and overall functioning measures over the study period, but with results indicating (via analysis of three sample subsets differing by the degree of 'actions taken') that those who took assertive action and had the diagnosis confirmed had the most superior outcome.

CONCLUSION

This is the first study to formally evaluate the clinical impact of a self-report bipolar disorder screening measure. High acceptance and superior outcomes quantified for those acting assertively in response to such a new diagnosis argue for its 'real world' utility.

Abstract 3757: Novel monoclonal antibodies for the analysis and isolation of Lgr5 positive cells

Cancer stem cells (CSCs), also called tumor initiating cells, have gained substantial interest in the research field over the past few years. CSCs have been isolated from multiple tumor entities and were shown to play a crucial role during tumor growth and metastasis. However, there is still a major debate about specific cell surface markers capable of identifying CSCs in most tumor entities. The leucine-rich repeat-containing G-protein-coupled receptor (LGR) Lgr5 and its close homologues Lgr4 and Lgr6 associate with Wnt-receptors and act as R-spondin receptors thereby playing a central role in the modulation of Wnt/β-catenin signaling in normal and neoplastic stem cells (de Lau et al., 2011, Carmon et al., 2011). Initially described as a highly specific marker for stem cells in the small intestine, colon, hair follicle, stomach, and during kidney development (Barker et al., 2007, Jaks et al., 2008, Barker et al., 2010, Barker et al., 2012), Lgr5 positive cells were also shown to be crucial during the development and progression of cancer. It was shown that Lgr5 positive crypt stem cells are the cells-of-origin in intestinal cancer and that CSCs in human colorectal cancer can be identified and isolated based on Lgr5 expression (Barker et al., 2009, Kemper et al., 2012). However, the analysis of Lgr5 expressing cells is hampered by the lack of highly specific monoclonal antibodies. We have developed rabbit monoclonal antibodies against peptide sequences of Lgr5. After generating cell lines stably expressing Lgr5, we screened for high affinity antibodies by flow cytometry. Using stable transfectants for Lgr4 and Lgr6, we could prove that there is no cross reactivity with its close homologues. This is of particular importance for Lgr4, as this protein is also expressed on more differentiated progenitor cells. To allow for identification, analysis, and isolation of Lgr5 positive cells from solid tissues, automated and therefore user-independent methods for tissue dissociation were developed. This resulted in enzyme mixtures which allow dissociating different tissues without harming the target epitopes. To detect cells expressing Lgr5 at low levels in flow cytometry based assays we combined our novel high affinity antibodies with fluorescence amplification systems. In addition, we generated a new magnetic cell separation (MACS) protocol that can be used as an easy and fast method to isolate Lgr5 positive cells from primary human tissue. Taken together, we have developed highly specific monoclonal antibodies allowing for the analysis and isolation of Lgr5 positive cells from cell lines and primary tissues.

Citation Format: David Agorku, Greg Parker, Nadine Chelius, Andreas Bosio, Olaf Hardt. Novel monoclonal antibodies for the analysis and isolation of Lgr5 positive cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3757. doi:10.1158/1538-7445.AM2013-3757