Sex Differences in Symptoms of Depression in Unrelated Individuals and Opposite-Sex Twin and Sibling Pairs

Prevalence of Anxiety and Burnout, and Coping Mechanisms among Clinical Year Medical Undergraduate Students in Universiti Kebangsaan Malaysia Amidst the COVID-19 Pandemic

This study aimed to determine the prevalence of anxiety and burnout, and the coping mechanisms among clinical year undergraduate medical students in Universiti Kebangsaan Malaysia (UKM) during the coronavirus disease 2019 (COVID-19) pandemic. In total, 378 clinical year undergraduate medical students in UKM participated in this cross-sectional study from May to July 2021. A self-administered questionnaire consisting of questions on the participant's sociodemographic data and items from the DASS-21, CBI, and Brief-COPE was distributed. Chi-square and Spearman's correlation tests were used to calculate the correlation coefficient between both anxiety and burnout, and coping mechanisms. The prevalence of anxiety and burnout were 44.2% and 22.2%, respectively. There was a significant difference in the percentage of students with extremely severe anxiety in the presence and absence of burnout, 23.8% vs. 4.8% (p < 0.001). Among the three coping mechanisms, avoidant coping had a significant positive moderate correlation with both the presence of anxiety (r = 0.3966, p < 0.001) and the presence of burnout (r = 0.341, p < 0.001). Meanwhile, coping that was neither approach nor avoidant had a positive weak correlation with the presence of burnout (r = 0.176, p = 0.001). The prevalence of anxiety and burnout was concerning. Increased anxiety and burnout among students may negatively impact aspects of their personal, professional, and academic lives. Early recognition and preventive measures should be emphasised to prevent negative ramifications.

Nick Martin and the Genetics of Depression: Sample Size, Sample Size, Sample Size

Nick Martin is a pioneer in recognizing the need for large sample size to study the complex, heterogeneous and polygenic disorders of common mental disorders. In the predigital era, questionnaires were mailed to thousands of twin pairs around Australia. Always quick to adopt new technology, Nick's studies progressed to phone interviews and then online. Moreover, Nick was early to recognize the value of collecting DNA samples. As genotyping technologies improved over the years, these twin and family cohorts were used for linkage, candidate gene and genome-wide association studies. These cohorts have underpinned many analyses to disentangle the complex web of genetic and lifestyle factors associated with mental health. With characteristic foresight, Nick is chief investigator of our Australian Genetics of Depression Study, which has recruited 16,000 people with self-reported depression (plus DNA samples) over a time frame of a few months - analyses are currently ongoing. The mantra of sample size, sample size, sample size has guided Nick's research over the last 30 years and continues to do so.

Measurement and genetic architecture of lifetime depression in the Netherlands as assessed by LIDAS (Lifetime Depression Assessment Self-report)

BACKGROUND

Major depressive disorder (MDD) is a common mood disorder, with a heritability of around 34%. Molecular genetic studies made significant progress and identified genetic markers associated with the risk of MDD; however, progress is slowed down by substantial heterogeneity as MDD is assessed differently across international cohorts. Here, we used a standardized online approach to measure MDD in multiple cohorts in the Netherlands and evaluated whether this approach can be used in epidemiological and genetic association studies of depression.

METHODS

Within the Biobank Netherlands Internet Collaboration (BIONIC) project, we collected MDD data in eight cohorts involving 31 936 participants, using the online Lifetime Depression Assessment Self-report (LIDAS), and estimated the prevalence of current and lifetime MDD in 22 623 unrelated individuals. In a large Netherlands Twin Register (NTR) twin-family dataset (n ≈ 18 000), we estimated the heritability of MDD, and the prediction of MDD in a subset (n = 4782) through Polygenic Risk Score (PRS).

RESULTS

Estimates of current and lifetime MDD prevalence were 6.7% and 18.1%, respectively, in line with population estimates based on validated psychiatric interviews. In the NTR heritability estimates were 0.34/0.30 (s.e. = 0.02/0.02) for current/lifetime MDD, respectively, showing that the LIDAS gives similar heritability rates for MDD as reported in the literature. The PRS predicted risk of MDD (OR 1.23, 95% CI 1.15-1.32, R2 = 1.47%).

CONCLUSIONS

By assessing MDD status in the Netherlands using the LIDAS instrument, we were able to confirm previously reported MDD prevalence and heritability estimates, which suggests that this instrument can be used in epidemiological and genetic association studies of depression.

Gender similarities in somatic depression and in DSM depression secondary symptom profiles within the context of severity and bereavement

BACKGROUND

Most population studies report higher rates of depression among women than men, and some researchers have observed gender differences in depression symptoms overall, or in sub-groupings (e.g. somatic depression). However, gender symptom differences have been inconsistent, prompting this investigation of gender differences in secondary DSM symptom profiles in the context of bereavement status, age, and depression severity.

METHODS

Individuals with symptoms of core depression (flat affect or anhedonia) were selected from a large survey of adults in the Alberta, Canada workforce. Analyses involved the comparison of gender profiles across the seven DSM-IV secondary depressive symptoms plus a MANOVA of sex, bereavement, and age, with secondary symptoms comprising the dependent variable.

RESULTS

Gender profiles were very similar, irrespective of depression severity or bereavement. Secondary symptoms were marginally more common among women and more frequent among bereaved young adults, but there was no evidence for a gender-related somatic factor.

LIMITATIONS

First, data were gathered only for persons in the workforce and thus may not be generalizable to, for example, stay-at-home parents or those with employment issues. Second, the focus here is restricted to DSM symptoms, leaving risk factors, social roles, and brain functioning for separate investigation. Third, inferences were drawn from associations between groups of persons, rather than between individuals, requiring caution when speculating about individual attributes.

CONCLUSIONS

Gender differences in depression represent a difference in amount, not kind, suggesting that the range of depressive experiences is similar for men and women. There was no gender difference ascribable to somatic depression.

Altered neuronal spontaneous activity correlates with glutamate concentration in medial prefrontal cortex of major depressed females: An fMRI-MRS study

BACKGROUND

Major depressive disorder (MDD) is twice more prevalent in females than in males. Yet, there have only been a few studies on the functional brain activity in female MDD patients and the detailed mechanisms underlying their neurobiology merit further investigations. In the present work, we used combined fMRI-MRS methods to investigate the altered intrinsic neuronal activity and its association with neurotransmitter concentration in female MDD patients.

METHODS

The whole brain amplitude of low frequency fluctuation (ALFF) analysis using resting state functional magnetic resonance imaging (fMRI) was performed to explore the alteration of intrinsic neuronal signals in MDD females (n=11) compared with female healthy controls (n=11). With a specific interest in the medial prefrontal cortex (mPFC) area, we quantified the concentration of amino acid neurotransmitters including GABA ((r-aminobutyric acid)), Glu (Glutamate), and Glx (Glutamate + Glutamine) using (1)H-MRS technology. Moreover, we conducted Pearson correlation analysis between the ALFF value and neurotransmitter concentration to find out the functional-biochemical relation in mPFC area. The relationship between the metabolites concentration and MDD symptomatology was also examined through Spearman correlation analysis.

RESULTS

We found that the female MDD patients showed increased neuronal spontaneous activity in left medial prefrontal cortex (mPFC) and left middle frontal cortex, with decreased ALFF level in right putamen and right middle temporal cortex (p<0.01, Alphasim corrected). The ALFF in mPFC was shown positively correlated with Glu concentration in female MDD patients (r=0.67, p=0.023). The Glu concentration in mPFC was positively correlated with patients HAMA scores (r=0.641, p=0.033).

LIMITATIONS

The relatively small sample size, metabolite information acquired only in mPFC and not all patients were unmedicated are the major limitations of our study.

CONCLUSIONS

Using combined fMRI-MRS methods, we found increased spontaneous neuronal activity was correlated with Glu concentration in mPFC of female MDD patients. Other regions including left middle frontal gyrus, right putamen and middle temporal gyrus also showed altered spontaneous neuronal activities. The abnormal intrinsic neuronal activities in fronto-cortical regions shed light on the pathogenesis underlying MDD females. The multimodal resting-state neuroimaging technique served as a useful tool for functional-biochemical investigation of MDD pathophysiology.

Utility of self-reported sleep disturbances as a marker for major depressive disorder (MDD): findings from the World Mental Health Japan Survey 2002-2006

Although major depressive disorder (MDD) is a serious common disease, many depressive patients seek primary care with complaints of sleep disturbances that remain undiagnosed. The purpose of this study was to investigate the utility of self-reported sleep disturbances as a marker for MDD. This study investigated the association between 12-month prevalence of self-reported sleep disturbances and MDD using data from a cross-sectional survey in Japan. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the area under the receiver operating characteristic curve (AUC) of self-reported sleep disturbances as a marker for MDD were 58.9%, 73.4%, 6.9%, 98.1%, and 0.66, respectively. Self-reported sleep disturbances showed highest utility for the youngest group. Among four types of sleep disturbances, the problem of daytime sleepiness was most useful as a marker for MDD. Combined with at least moderate role impairment, self-reported sleep disturbances became more informative with higher specificity (99.6%) and PPV (80.0%) as a marker for MDD. Self-reported sleep disturbances cannot be a marker for MDD in isolation. Comorbid role impairment increases the probability of MDD. Clinicians should be cautious in assessments of young people who have sleep disturbances. Daytime sleepiness should be included among the questions asked when inquiring about sleep disturbances.

Revisiting gender differences in somatic symptoms of depression: much ado about nothing?

BACKGROUND

Women have a higher prevalence of Major Depressive Disorder (MDD) and report more severe depressive symptoms than men. Several studies have suggested that gender differences in depression may occur because women report higher levels of somatic symptoms than men. Those studies, however, have not controlled or matched for non-somatic symptoms. The objective of this study was to examine if women report relatively more somatic symptoms than men matched on cognitive/affective symptoms.

METHODS

Male and female patients receiving treatment for MDD in outpatient psychiatric clinics in New Jersey and Pennsylvania, USA were matched on Beck Depression Inventory-II (BDI-II) cognitive/affective symptom scores. Male and female BDI-II somatic symptom scores were compared using independent samples 2-tailed t-tests.

RESULTS

Of 472 male and 1,026 female patients, there were 470 male patients (mean age = 40.1 years, SD = 15.1) and 470 female patients (mean age = 43.1 years, SD = 17.2) successfully matched on BDI-II cognitive/affective symptom scores. Somatic symptoms accounted for 35% of total BDI-II scores for male patients versus 38% for matched female patients. Female patients had somatic symptom scores on average 1.3 points higher than males (p<.001), equivalent to 4% of the total BDI-II scores of female patients. Only 5% of male patients and 7% of female patients scored 2 or higher on all BDI-II somatic symptom items.

CONCLUSIONS

Gender differences in somatic scores were very small. Thus, differences in the experience and reporting of somatic symptoms would not likely explain gender differences in depression rates and symptom severity.

Strong genetic correlation between interview-assessed internalizing disorders and a brief self-report symptom scale

Self-report scales for symptoms of anxiety and depression are frequently used for screening and research purposes. A moderate phenotypic association between disorders measured by diagnostic interviews and symptoms of anxiety and depression measured by self-report scales has been shown, but little is known about the overlap in these phenotypes' genetic and environmental variance. In the present study, we used twin modeling to identify common genetic and environmental liabilities underlying the phenotypic association between the self-report Symptom Checklist-5 (SCL-5) and lifetime internalizing disorders derived from the Composite International Diagnostic Interview (CIDI). The sample consisted of 7,992 young adult twins from the Norwegian Institute of Public Health Twin Panel (NIPHT), who all responded to a questionnaire. A subset of 2,793 individuals later underwent structured interviews. The best fitting model showed a strong genetic correlation of 0.82 (95% confidence interval; 0.61-1.0) between current self-report symptoms of anxiety and depression, and lifetime internalizing disorders, which suggests an almost complete overlap in genetic liability. The correlation between environmental factors was much lower: 0.16 (0.00-0.34, 95% CI). This implies that brief self-report scales capture genetic variance that is highly overlapping with the genetic variance common to internalizing disorder diagnoses. It thus follows that SCL-5 and similar instruments may be used as screening instruments for genetic risk factors that influence liability to internalizing disorders. In addition, existing data on self-report symptoms of anxiety and depression can be used with increased confidence to specify models including effects from genes coding for internalizing disorders.

Gender differences in affective suffering among racial/ethnically diverse, community-dwelling elders

Objective. Copious research shows a female excess of unipolar depression. The generalizability of this finding is examined in a racial/ethnically diverse, community-residing, elder sample. Design. Depressive suffering was assessed both categorically and linearly with the Index of Affective Suffering (IAS), a hierarchal measure designed to examine intensity and extensity of suffering. In-home interviews by specially trained raters also collected demographic, functional, and social health data. Prevalence rates of affective suffering were examined separately for Latinos (N=996, Females=46.8%), Blacks (N=717, Females=36.5%), and Whites (N=415, Females=18.6%). Results. Analyzed by gender alone these data support the typical wisdom that females report significantly more depressed affect than males. However, by racial/ethnic group categorical analysis indicates that among Whites and Latinos, women reported more symptoms of clinically significant affective suffering than males; whereas, among Blacks, women and men did not differ from each other. Moreover, risk factors commonly associated with excess female depression failed to explain observed differences. Conclusion. The absence of a between-gender difference in affective suffering observed among Black elders in this study raises questions about generalized assumptions of greater 'female' vulnerability for this age group. A need for research to appreciate the heterogeneity of elder individuals is highlighted as is the importance of using dimensional assessment techniques in psychiatric epidemiology.

Deconstructing major depression: a validation study of the DSM-IV symptomatic criteria

BACKGROUND

The DSM-IV symptomatic criteria for major depression (MD) derive primarily from clinical experience with modest empirical support.

METHOD

The sample studied included 1015 (518 males, 497 females) Caucasian twins from a population-based registry who met criteria for MD in the year prior to the interview. Logistic regression analyses were conducted to compare the associations of: (1) single symptomatic criterion, (2) two groups of criteria reflecting cognitive and neurovegetative symptoms, with a wide range of potential validators including demographic factors, risk for future episodes, risk of MD in the co-twin, characteristics of the depressive episode, the pattern of co-morbidity and personality traits.

RESULTS

The individual symptomatic criteria showed widely varying associations with the pattern of co-morbidity, personality traits, features of the depressive episode and demographic characteristics. When examined separately, these two criteria groups showed robust differences in their patterns of association, with the validators with the cognitive criteria generally producing stronger associations than the neurovegetative.

CONCLUSIONS

Among depressed individuals, individual DSM-IV symptomatic criteria differ substantially in their predictive relationship with a range of clinical validators. These results challenge the equivalence assumption for the symptomatic criteria for MD and suggest a more than expected degree of 'covert' heterogeneity among these criteria. Part of this heterogeneity is captured by the distinction between cognitive versus neurovegetative symptoms, with cognitive symptoms being more strongly associated with most clinically relevant characteristics. Detailed psychometric evaluation of DSM-IV criteria is overdue.

Gender differences in clinical characteristics in a naturalistic sample of depressive outpatients: the Leiden Routine Outcome Monitoring Study

BACKGROUND

No previous large scale studies have assessed gender differences in naturalistic samples of major depressive disorder (MDD) outpatients. We therefore determined gender differences in comorbidity, symptom patterns and subjective health status in these outpatients in a mental healthcare setting.

METHODS

Of 3798 consecutive adult patients (age range: 18-65), 1131 (65.1% women) fulfilled DSM-IV criteria of current MDD on the Mini-International Neuropsychiatric Interview (MINI-Plus). Patients were routinely assessed with Routine Outcome Monitoring (ROM), including the Montgomery-Asberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI-II), Brief Symptom Inventory (BSI) and Short Form-36 (SF-36).

RESULTS

No gender differences were found in disease severity using the clinician-rated MADRS. However, women showed a significant higher depression severity measured with the self-report BDI-II. Also, psychopathological symptoms self-reported with the BSI were higher, and reported health status on the SF-36 was lower in women. In men with MDD, social phobia, attention deficit hyperactivity disorder, and alcohol and drug misconduct were more common comorbid disorders, while in women with MDD posttraumatic stress disorder and bulimia nervosa were more common, as well as atypical features of depression.

LIMITATIONS

The use of retrospective reports of lifetime psychopathology might have led to recall bias. 20% of subjects were excluded from ROM due to language problems or logistical reasons.

CONCLUSIONS

Although women self-reported higher depression severity, more severe general psychopathological symptoms and lower health status, no differences in disease severity were found on interviewer ratings. These findings could have implications for clinical decision making and treatment.

Epidemiology and symptomatology of depression in Sri Lanka: a cross-sectional population-based survey in Colombo District

BACKGROUND

It is important to understand the nature of depression in non-Western and lower-income countries, but little such research exists. This study aimed to examine the characteristic features of depression in Sri Lanka, and to identify environmental risk factors.

METHODS

Depression diagnoses, symptoms and impairment were measured using the Composite International Diagnostic Interview, in a population-based sample of 6014 twins and non-twins in the Colombo region of Sri Lanka (the CoTASS sample). Socio-demographic factors and environments were assessed via questionnaires.

RESULTS

Lifetime-ever depression was reported in 6.6% of participants, rising to 11.2% if the functional impairment criterion was excluded. The symptom profile of depression and its socio-demographic associations were very comparable to those in Western and more economically developed countries, whether functional impairment was included in the definition or not. Standard of living was independently associated with depression, especially among men at the more deprived end of the distribution. Specific associations were found with both financial wellbeing and material characteristics of the home environment.

LIMITATIONS

The observational associations identified are cross-sectional, so do not necessarily imply causal links.

CONCLUSIONS

Aside from a lower prevalence, depression is very similar in this predominantly urban Sri Lankan sample to higher-income, Western countries, and may be under-identified due to a relatively low cultural appropriateness of the assessment of impairment. Under Sri Lanka's cultural and environmental context, certain aspects of the material environment are associated with depression among certain segments of society, perhaps because of their particular link to social status and social networks.

Influence of repetitive transcranial magnetic stimulation on psychomotor symptoms in major depression

Psychomotor symptoms related to an impairment of the nigrostriatal dopaminergic system are frequent in major depression (MD). Repetitive transcranial magnetic stimulation (rTMS) has been discussed as a new treatment option for MD. In neurobiological terms, an influence of high-frequency rTMS on dopaminergic neurotransmission has previously been shown by several studies in animals and humans. Therefore, an improvement of psychomotor symptoms by rTMS could be assumed. The aim of this pilot study was to investigate the effect of high-frequency rTMS on psychomotor retardation and agitation in depressive patients. We investigated the effect of left prefrontal 10 Hz rTMS on psychomotor retardation and agitation in 30 patients with MD. Patients were randomly assigned to real or sham rTMS in addition to a newly initiated standardized antidepressant medication. We found a trend in the reduction of agitation (t(28) = 1.76, p = 0.09, two-tailed), but not in the reduction of retardation. Furthermore, no general additional antidepressant effect of rTMS was observed. Although there was no statistical significant influence of high-frequency rTMS on psychomotor symptoms in depressive patients, the results showed a trend in the reduction of psychomotor agitation in MD. This effect should be systematically investigated as the primary end point in further studies with larger sample sizes.

Genetic and environmental contributions to depression in Sri Lanka

BACKGROUND

Susceptibility to depression results from genetic and non-familially shared environmental influences in high-income, Western countries. Environments may play a different role for populations in different contexts.

AIMS

To examine heritability of depression in the first large, population-based twin study in a low-income country.

METHOD

Lifetime depression and a broader measure of depression susceptibility (D-probe) were assessed in 3908 adult twins in Sri Lanka (the CoTASS study).

RESULTS

There were gender differences for the broad definition (D-probe), with a higher genetic contribution in females (61%) than males (4%). Results were similar for depression, but the prevalence was too low to estimate heritability for males.

CONCLUSIONS

Genetic influences on depression in women appear to be at least as strong in this Sri Lankan sample as in higher-income countries. Conclusions are less clear for men but suggest a larger role for environments rather than genes. The nature as well as the magnitude of environmental influences may also differ across populations.

Sex differences in symptom patterns of recurrent major depression in siblings

The objectives of this study were to examine sex differences in depressive symptom patterns in 475 sib pairs with well-defined recurrent major depression and to test the hypotheses that (a) symptom patterns show higher intraclass correlations within same sex sib pairs versus mixed sex sib pairs; and (b) symptoms more associated with women, e.g. atypical depressive and anxiety symptoms, account for differences between male and female siblings within the same family. A total of 878 individuals, with a past history of at least two depressive episodes, were interviewed using the Schedules for Clinical Assessment in Neuropsychiatry interview and diagnosed according to DSM-IV using a computerized scoring program (CATEGO5). Intraclass correlations were compared between mixed and same sex sibs, and a conditional regression analysis in mixed sex sib pairs was performed to test whether specific symptoms account for differences between male and female siblings within the same family. Women showed a significantly earlier onset of depression compared with men (23.0 years, SD=10.6 versus 25.5, SD=12.5 years, P=0.0004), and a significantly greater frequency of several aspects of depressed mood was found in women compared with men, including atypical depressive features of fatiguability, appetite gain, weight gain and hypersomnia. Discordant sib-pair data analyses revealed five symptoms that accounted for the sex differences between siblings (P=.000035): phobia (exp(B)=2.04, P=0.017), hypersomnia (exp(B)=1.37, P=0.055), appetite loss (exp(B)=1.38, P=0.004) and appetite gain (exp(B)=2.19, P<0.001). Sex significantly modifies clinical features of depression and an earlier onset of depression and atypical depressive symptoms occur more frequently in women.

Heritability of parturition timing: an extended twin design analysis

OBJECTIVE

The objective of the study was to assess relative maternal and paternal genetic influences on birth timing.

STUDY DESIGN

Utilizing The Netherlands Twin Registry, we examined the correlation in birth timing of infants born to monozygotic (MZ) twins and their first-degree relatives (dizygotic twins and siblings of twins). Genetic models estimated the relative influence of genetic and common environmental factors through model fitting of additive genetic (A), common environmental (C), individual-specific environmental factors, and combinations thereof.

RESULTS

We evaluated birth timing correlation among the infants of 1390 twins and their 644 siblings. The correlation in MZ female twins (r = 0.330) was greater than MZ male twins (r = -0.096). Positive correlation were also found in sister-sister pairs (r = 0.223) but not in brother-brother (r = -0.045) or brother-sister pairs (r = -0.038). The most parsimonious AE model indicated a significant maternal contribution of genetic and individual-specific environmental factors to birth timing, but no paternal heritability was demonstrated. Heritability of birth timing in women was 34%; and the remaining variance (66%) was caused by individual-specific environmental factors.

CONCLUSION

Our data implicate a significant contribution of maternal but not paternal genetic influences on birth timing.

Differences in depressive symptom profile between males and females

BACKGROUND

It is widely held that there are no differences in the symptom profile of male and female depression. Studies to date that have found differences have used different methodologies and had inconsistent findings. Here we compare the clinical profile of major depression for men and women from a sample of almost 600 well-characterized individuals with recurrent major depressive disorder (MDD).

METHODS

Subjects were recruited as part of a large genetic-epidemiological study of MDD. Clinical assessments included semi-structured interviews and case-note review. Clinical profiles during 'worst ever' (WE) depressive episode were scored using the OPCRIT checklist. Profiles for 199 males were compared to 399 females.

RESULTS

Females with depression tended to have an earlier age-at-onset (p<0.0001), exhibited more frequent depressive episodes (p<0.005), had a greater number of depressive symptoms (p<0.001), and reported much higher rates of atypical depressive features (p<0.007) during their WE episode of depression. Logistic regression analysis identified that earlier age-at-onset of depression, excessive self-reproach and diminished libido were the best predictors of female depression.

LIMITATIONS

Retrospective recall by subjects of depressive symptoms, which may be prone to recall bias.

CONCLUSIONS

There are differences in the clinical course and symptom profile of male and female depression. Further study is required to identify the biological correlates of these differences and to characterize their clinical importance.