The multiple interactional biological processes that might lead to depression and gender differences in its appearance

Machine learning analyses reveal circadian clock features predictive of anxiety among UK biobank participants

Mood disorders, including depression and anxiety, affect almost one-fifth of the world's adult population and are becoming increasingly prevalent. Mutations in circadian clock genes have previously been associated with mood disorders both directly and indirectly through alterations in circadian phase, suggesting that the circadian clock influences multiple molecular pathways involved in mood. By targeting previously identified single nucleotide polymorphisms (SNPs) that have been implicated in anxiety and depressive disorders, we use a combination of statistical and machine learning techniques to investigate associations with the generalized anxiety disorder assessment (GAD-7) scores in a UK Biobank sample of 90,882 individuals. As in previous studies, we observed that females exhibited higher GAD-7 scores than males regardless of genotype. Interestingly, we found no significant effects on anxiety from individual circadian gene variants; only circadian genotypes with multiple SNP variants showed significant associations with anxiety. For both sexes, severe anxiety is associated with a 120-fold increase in odds for individuals with CRY2_AG(rs1083852)/ZBTB20_TT(rs1394593) genotypes and is associated with a near 40-fold reduction in odds for individuals with PER3-A_CG(rs228697)/ZBTB20_TT(rs1394593) genotypes. We also report several sex-specific associations with anxiety. In females, the CRY2/ZBTB20 genotype combination showed a > 200-fold increase in odds of anxiety and PER3/ZBTB20 and CRY1 /PER3-A genotype combinations also appeared as female risk factors. In males, CRY1/PER3-A and PER3-B/ZBTB20 genotype combinations were associated with anxiety risk. Mediation analysis revealed direct associations of CRY2/ZBTB20 variant genotypes with moderate anxiety in females and CRY1/PER3-A variant genotypes with severe anxiety in males. The association of CRY1/PER3-A variant genotypes with severe anxiety in females was partially mediated by extreme evening chronotype. Our results reinforce existing findings that females exhibit stronger anxiety outcomes than males, and provide evidence for circadian gene associations with anxiety, particularly in females. Our analyses only identified significant associations using two-gene combinations, underscoring the importance of combined gene effects on anxiety risk. We describe novel, robust associations between gene combinations involving the ZBTB20 SNP (rs1394593) and risk of anxiety symptoms in a large population sample. Our findings also support previous findings that the ZBTB20 SNP is an important factor in mood disorders, including seasonal affective disorder. Our results suggest that reduced expression of this gene significantly modulates the risk of anxiety symptoms through direct influences on mood-related pathways. Together, these observations provide novel links between the circadian clockwork and anxiety symptoms and identify potential molecular pathways through which clock genes may influence anxiety risk.

Dietary Zinc Intake Affects the Association Between Dietary Vitamin A and Depression: A Cross-Sectional Study

Introduction

Dietary vitamin A concentrations correlate with depression. Zinc has been reported to be associated with lower depression. In addition, zinc is an important cofactor in the activation of vitamin A. However, there are few studies investigating relationships between of dietary zinc intake, dietary vitamin A intake and depression.

Materials and Methods

The data for this study came from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018 and involved 70,190 participants. We stratified participants by recommended dietary zinc intake (recommended dietary zinc intake for women: 8 mg/day, recommended dietary zinc intake for men: 11 mg/day). We further assessed the association between vitamin A and depression in participants with low and high zinc intake (interaction test) using univariate logistic regression of intake participants.

Result

In the female population we grouped the population into low and high zinc intake groups using the recommended dietary zinc intake of 8 (mg/day), with an increase in total vitamin A, the risk of depression was significantly lower in the low zinc intake group (OR: 0.85 95 CI: 0.76–0.96), while the risk of depression was increased in the high zinc intake group (OR: 1.05 95 CI: 0.95 to 1.17). Thus, in the female population, there was a significant interaction between insufficient vitamin an intake and depression (interaction likelihood ratio test of p = 0.011). In the male population we grouped the population by the recommended dietary zinc intake of 11(mg/day). Again, the population was divided into two groups with low and high zinc intake, however we did not find significant results for the interaction (p = 0.743 for the interaction likelihood ratio test).

Conclusion

Our findings suggest that zinc intake may influence the relationship between dietary vitamin A and depression. Of course, our findings require further randomized controlled trials to enhance the credibility.

Machine learning and expression analyses reveal circadian clock features predictive of anxiety

Mood disorders, including generalized anxiety disorder, are associated with disruptions in circadian rhythms and are linked to polymorphisms in circadian clock genes. Molecular mechanisms underlying these connections may be direct-via transcriptional activity of clock genes on downstream mood pathways in the brain, or indirect-via clock gene influences on the phase and amplitude of circadian rhythms which, in turn, modulate physiological processes influencing mood. Employing machine learning combined with statistical approaches, we explored clock genotype combinations that predict risk for anxiety symptoms in a deeply phenotyped population. We identified multiple novel circadian genotypes predictive of anxiety, with the PER3(rs17031614)-AG/CRY1(rs2287161)-CG genotype being the strongest predictor of anxiety risk, particularly in males. Molecular chronotyping, using clock gene expression oscillations, revealed that advanced circadian phase and robust circadian amplitudes are associated with high levels of anxiety symptoms. Further analyses revealed that individuals with advanced phases and pronounced circadian misalignment were at higher risk for severe anxiety symptoms. Our results support both direct and indirect influences of clock gene variants on mood: while sex-specific clock genotype combinations predictive of anxiety symptoms suggest direct effects on mood pathways, the mediation of PER3 effects on anxiety via diurnal preference measures and the association of circadian phase with anxiety symptoms provide evidence for indirect effects of the molecular clockwork on mood. Unraveling the complex molecular mechanisms underlying the links between circadian physiology and mood is essential to identifying the core clock genes to target in future functional studies, thereby advancing the development of non-invasive treatments for anxiety-related disorders.

Personality, gender, and crying

This study examined gender differences in crying as well as associations between basic personality traits and self‐reported indices of crying. Forty‐eight men and 56 women completed the Five‐Factor Personality Inventory and the Adult Crying Inventory. Substantial gender differences were demonstrated in crying frequency and crying proneness, but not with respect to mood changes after crying. As predicted, women reported a higher frequency of crying and more proneness to cry both for negative and positive reasons. For women, all these crying indices were negatively associated with Emotional Stability. For men, only a significant negative relationship between Emotional Stability and crying for negative reasons emerged. No clear links were found between personality and mood changes after crying. Multiple regression analysis revealed a significant predictive role of gender for crying proneness, even when controlling for personality differences, but not for crying frequency. Adding personality by gender interaction terms resulted in a disappearance of the main effect of sex, while significant interactions with personality factors showed up for crying frequency and general crying proneness. It is suggested that future research on the relationship between personality and crying should focus more on the underlying mechanisms of observed relationships. Furthermore, it is recommended that future research should examine the role of different emotion regulation strategies. In addition, biological factors, temperament, upbringing measures, and socio‐demographic variables should be taken into account. Copyright © 2001 John Wiley & Sons, Ltd.

The relationship between adverse childhood experiences and depression: A cross-sectional survey with university students in Botswana

BACKGROUND

Adverse childhood experiences (ACEs) are associated with severe life-long negative outcomes, including depression. Particularly in low- and middle-income countries, few studies have been conducted to assess the impact of ACEs.

AIM

To assess the influence of ACEs on depression among young adults.

SETTING

Participants were students at a large university in Gaborone, Botswana.

METHODS

Using a cross-sectional design, we investigated the associations between ACEs and depression in young adults in Botswana (n = 392, mean age = 22.2, ± 2.5, 53.4% female). Bivariate correlation analyses, t-tests and analyses of variance (ANOVA) were performed to assess associations and compare ACEs at different levels of depression.

RESULTS

A total of 73% (n = 287) reported one or more ACEs, whilst 15% (59) reported five or more ACEs. About 64% (38) of those who reported five or more ACEs were female respondents. Prevalence of specific ACEs ranged from 9.5% (child neglect) to 36.3% (separation and divorce). One in three respondents reported parental separation or divorce, psychological abuse and family dysfunction, whilst 19% (11% moderate and 8% severe) reported significant depressive symptoms. Adverse childhood experiences significantly predicted depression (β = 0.27, 95% confidence interval [CI]: 0.18, 0.37). Respondents at different levels of depression significantly differed on reporting ACEs (F (3, 389) = 11.43, p < 0.001).

CONCLUSION

Adverse childhood experiences are highly prevalent and key determinants of depression in young adulthood. A multifaceted and cross-system intervention (e.g. schools, social work, psychological services, health services and law enforcement) is required to protect, prevent and treat survivors of childhood adversity.

Association between Lower Intake of Minerals and Depressive Symptoms among Elderly Japanese Women but Not Men: Findings from Shika Study

The aim of this cross-sectional study was to examine the relationship of mineral intake, including sodium, potassium, calcium, magnesium, phosphorus, iron, zinc, copper and manganese, with depressive symptoms in both genders in the Japanese elderly population. A total of 1423 participants who were older than 65 years old were recruited in this study. Mineral intake was analyzed using a validated and brief self-administered diet history questionnaire. Depressive symptoms were assessed with a short version of the Geriatric Depression Scale. A logistic regression model was applied to determine the relationship between mineral intake and depressive symptoms. The prevalence of depressive symptoms was 20%. Except for sodium and manganese, mineral intake was significantly lower in the depressive symptoms group. There was no difference of mineral intake between male participants with depressive symptoms and those without such symptoms. However, in female participants, mineral intake was significantly lower in participants with depressive symptoms compared to those without such symptoms. Potassium, calcium, magnesium, phosphorus, iron, zinc, and copper were significantly and negatively correlated with depressive symptoms among female participants, but not male participants. Our results suggest that the deficiencies in mineral intake may be related to depressive symptoms, especially in women.

Sex Differences in the Relationship between Depressive Symptoms and Risk of Amnestic Mild Cognitive Impairment

OBJECTIVE

The relationship between depressive symptoms and subsequent cognitive impairment in older adults is controversial. Sex differences and the differences in the method of categorizing depressive symptoms may contribute to the inconsistencies. The authors examined the effect of severity of baseline depressive symptoms on risk of incident amnestic mild cognitive impairment (aMCI) separately in men and women.

METHODS

Community-dwelling and cognitively healthy older adults (aged ≥ 70 years) from the Einstein Aging Study completed the 15-item Geriatric Depression Scale (GDS-15) at their baseline visit. Participants were categorized into "no/low symptoms" (GDS-15 score = 0-2), "mild symptoms" (GDS-15 score = 3-5), and "moderate/severe symptoms" (GDS-15 score > 6) groups. Sex-stratified Cox proportional hazards models, adjusted for age, education, and antidepressant medication, estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for incident aMCI as a function of depressive symptoms group.

RESULTS

We followed 572 women (mean age: 78) and 345 men (mean age: 77) for 4.2 years on average (range: 1.0-14.6 years). Ninety women and 64 men developed aMCI during follow-up. Cox models revealed that compared with no/low depressive symptoms, mild symptoms were associated with a two times greater risk of developing aMCI in men (HR: 2.22; 95% CI: 1.26-3.89) but not in women (HR: 1.26; 95% CI: 0.77-2.06). Conversely, moderate/severe depressive symptoms were associated with a two times greater risk of developing aMCI in women (HR: 1.99; 95% CI: 1.05-3.77) but not in men (HR: 0.28; 95% CI: 0.04-2.11), possibly because of low statistical power in this subgroup.

CONCLUSION

Results indicate that mild depressive symptoms in men and moderate/severe symptoms in women may represent a marker for future cognitive impairment.

Stressful Life Events and Risk of Depression 25 Years Later: Race and Gender Differences

BACKGROUND

Although stressful life events (SLEs) predict subsequent risk of developing a major depressive episode (MDE), limited information exists on whether or not race and gender alters the predictive role of SLE on risk of MDE over a long-term period. The current study explored race and gender differences in the long-term predictive role of SLE at baseline (1986) on subsequent risk of MDE 25 years later (2011) in a nationally representative cohort in the United States.

METHODS

Using a life course epidemiological approach, this longitudinal study borrowed data from the Americans' Changing Lives (ACL) Study 1986-2011. Main predictor of interest was baseline SLE over the last 3 years measured at 1986. Main outcome was risk of MDE [Composite International Diagnostic Interview (CIDI)] 25 years later (2011). Covariates included demographics, socioeconomics, depressive symptoms [Center for Epidemiological Studies-Depression Scale (CES-D)], chronic medical conditions, and health behaviors measured at baseline (1986). Gender and race were the focal moderators. We employed logistic regressions in the pooled sample, and specific to race and gender, to test whether or not SLE × race and SLE × gender interactions are significant.

RESULTS

In the pooled sample, baseline SLE (1986) predicted risk of MDE 25 years later (2011). We also found a gender by SLE interaction, suggesting a stronger predictive role of SLE for subsequent clinical depression for men compared to women. Race did not modify the predictive role of SLE on subsequent risk of MDE 25 years later.

CONCLUSION

How SLE predicts MDE 25 years later differs for men and women, with a stronger predictive role for men compared to women. More research is needed to better understand the complex links between gender, sex, stress, and depression.

Molecular analyses of circadian gene variants reveal sex-dependent links between depression and clocks

An extensive literature links circadian irregularities and/or sleep abnormalities to mood disorders. Despite the strong genetic component underlying many mood disorders, however, previous genetic associations between circadian clock gene variants and major depressive disorder (MDD) have been weak. We applied a combined molecular/functional and genetic association approach to circadian gene polymorphisms in sex-stratified populations of control subjects and case subjects suffering from MDD. This approach identified significant sex-dependent associations of common variants of the circadian clock genes hClock, hPer3 and hNpas2 with major depression and demonstrated functional effects of these polymorphisms on the expression or activity of the hCLOCK and hPER3 proteins, respectively. In addition, hCLOCK expression is affected by glucocorticoids, consistent with the sex-dependency of the genetic associations and the modulation of glucocorticoid-mediated stress response, providing a mechanism by which the circadian clock controls outputs that may affect psychiatric disorders. We conclude that genetic polymorphisms in circadian genes (especially hClock and hPer3, where functional assays could be tested) influence risk of developing depression in a sex- and stress-dependent manner. These studies support a genetic connection between circadian disruption and mood disorders, and confirm a key connection between circadian gene variation and major depression.

The Effects of Gender Differences in Patients with Depression on Their Emotional Working Memory and Emotional Experience

A large amount of research has been conducted on the effects of sex hormones on gender differences in patients with depression, yet research on cognitive differences between male and female patients with depression is insufficient. This study uses emotion pictures to investigate the differences of the emotional working memory ability and emotional experience in male and female patients with depression. Despite identifying that the working memory of patients with depression is impaired, our study found no significant gender differences in emotional working memory. Moreover, the research results revealed that memory effects of mood congruence are produced in both men and women, which may explain why the depression state can be maintained. Furthermore, female patients have more emotional experiences than male patients, which is particularly significant in terms of negative emotional experiences. This result provides cognitive evidence to explain why women suffer from longer terms of depression, are more susceptible to relapse, and can more easily suffer from major depressive disorder in the future.

Behavioural and neurobiological consequences of macrophage migration inhibitory factor gene deletion in mice

Background

Evidence from clinical studies and animal models show that inflammation can lead to the development of depression. Macrophage migration inhibitory factor (MIF) is an important multifunctional cytokine that is synthesized by several cell types in the brain. MIF can increase production of other cytokines, activates cyclooxygenase (COX)-2 and can counter-regulate anti-inflammatory effects of glucocorticoids. Increased plasma levels of MIF are associated with hypothalamic–pituitary–adrenal (HPA) axis dysregulation and depressive symptoms in patients. In contrast, MIF knockout (KO) mice have been found to exhibit increased depressive-like behaviour. The exact role for MIF in depression is therefore still controversial. To further understand the role of MIF in depression, we studied depressive-like behaviour in congenic male and female MIF KO mice and wild-type (WT) littermates and the associated neurobiological mechanisms underlying the behavioural outcome.

Methods

MIF KO and WT mice were tested for spontaneous locomotor activity in the open-field test, anhedonia-like behaviour in the sucrose preference test (SPT), as well as behavioural despair in the forced swim test (FST) and tail suspension test (TST). Brain and serum levels of cytokines, the enzymes COX-2 and indoleamine-2,3-dioxygenase (IDO) and the glucocorticoid hormone corticosterone were measured by RT-qPCR and/or high-sensitivity electrochemiluminescence-based multiplex immunoassays. Monoamines and metabolites were examined using HPLC.

Results

We found that MIF KO mice of both sexes displayed decreased depressive-like behaviour as measured in the FST. In the TST, a similar, but non-significant, trend was also found. IFN-γ levels were decreased, and dopamine metabolism increased in MIF KO mice. Decreased brain IFN-γ levels predicted higher striatal dopamine levels, and high dopamine levels in turn were associated with reduced depressive-like behaviour. In the SPT, there was a sex-specific discrepancy, where male MIF KO mice showed reduced anhedonia-like behaviour whereas female KO mice displayed increased anhedonia-like behaviour. Our results suggest that this relates to the increased corticosterone levels detected in female, but not male, MIF KO mice.

Conclusions

Our findings support that MIF is involved in the generation of depressive-like symptoms, potentially by the effects of IFN-γ on dopamine metabolism. Our data further suggests a sex-specific regulation of the involved mechanisms.

Sex and estrogen affect the distribution of urocortin-1 immunoreactivity in brainstem autonomic nuclei of the rat

Urocortin-1 (UCN-1), a neuropeptide closely related to the hypothalamic hormone corticotropin-releasing factor, has been associated with stress, feeding behaviors, cardiovascular control, and to exhibit functional gender differences. This study was done to investigate whether estrogen (E; 17β-estradiol) treatment (9 weeks) altered UCN-1 immunoreactivity in brainstem autonomic nuclei in female Wistar rats. Experiments were done in age matched adult males (controls), females (intact), and ovariectomized (OVX) only and OVX+E (30pg/ml plasma) treated females. All animals received intracerebroventricular injections of colchicine and were then perfused transcardially with Zamboni's fixative. Coronal brainstem sections (40μm) were cut and processed immunohistochemically for UCN-1. In males, moderate UCN-1 fiber labeling was found in the nucleus of the solitary tract (NTS) and throughout the rostral ventral lateral medulla (RVLM). Additionally, a few UCN-1 immunoreactive neurons were observed in hypoglossal nucleus (XII), facial nucleus (FN) and nucleus ambiguus (Amb). In intact females and OVX+E females, fewer UCN-1 labeled fibers were found within NTS compared to males. In contrast, the RVLM was more densely innervated in the female cases. Furthermore, in both intact and OVX+E females UCN-1 labeled neurons were found not only within Amb, FN and XII, but also within NTS, RVLM and nucleus raphé pallidus (RP). In OVX only animals, moderate to dense UCN-1 fiber labeling was observed in the NTS complex and throughout RVLM compared to males and the other female groups. However, in contrast to all other groups, UCN-1 labeled neurons were found in greater number within Amb, FN, NTS, dorsal motor nucleus of the vagus, XII, RVLM, magnocellular reticular nucleus and RP. These data not only suggest that sex differences exist in the distribution of UCN-1 within brainstem autonomic areas, but that circulating level of E may play an important role with regards to the function of these UCN-1 neurons during stress responses.

How equal is the relationship between individual social capital and psychological distress? A gendered analysis using cross-sectional data from Ghent (Belgium)

BACKGROUND

Social capital has been related to various aspects of health. While literature suggests that men and women differently access and mobilize social capital, gender has received little attention within social capital research. This study examines whether the association between individual social capital and psychological distress is different for men and women.

METHODS

We made use of data from a representative sample of 1025 adults within 50 neighbourhoods of Ghent (Belgium), collected in the context of the cross-sectional Social capital and Well-being In Neighbourhoods in Ghent (SWING) Survey 2011. Six components of social capital were discerned: generalized trust, social support, social influence, social engagement and attachment, the volume of social capital and the mean occupational prestige in one's network. Multilevel linear regression models were fitted to explore interactions between gender and these components of social capital.

RESULTS

In accordance with previous research, men report lower levels of psychological distress than women (t = 4.40, p < 0.001). Regarding the gender gap in social capital, the findings are mixed. Only for half of the social capital variables (social support, social influence and volume of social capital), a significant gender difference is found, favouring men (t = 4.03, p < 0.001; t = 1.99, p < 0.001 and t = 4.50, p < 0.001 respectively). None of the analysed interaction terms between gender and social capital is significantly related to psychological distress.

CONCLUSION

The analyses indicate that the association between individual social capital and psychological distress is similar for men and women. The relatively low level of gender stratification in Belgium might have influenced this finding. Furthermore, it is possible that social capital is not of greater importance for women in general, but mainly for women who are in an especially vulnerable social situation that deprives their access to alternative resources (e.g. unemployed women, single mothers). Future studies should seek to identify subgroups for whom social capital might be particularly influential, by transcending 'simple' dyads such as 'men versus women'.

Avaliação do funcionamento do eixo HPA em deprimidos por meio de medidas basais: revisão sistemática da literatura e análise das metodologias utilizadas

Objetivo Realizar revisão sistemática da literatura para conhecer a atividade do eixo hipotálamo-pituitária-adrenal (HPA) em deprimidos considerando-se as medidas basais dos hormônios e analisar criticamente as metodologias utilizadas. Métodos Foi realizada busca de artigos nas bases de dados PubMed e SciELO. Na primeira base de dados, introduziram-se as palavras-chave “depressive disorder” e “HPA axis”, e na segunda utilizaram-se os termos “depression” ou “depressão” e “HHA” ou “HPA axis”. Optou-se por pesquisa realizada em humanos adultos, em inglês e português, do ano 2000 até 2011. Resultados Dos 27 artigos selecionados, obtiveram-se como resposta do eixo HPA tanto hiperatividade como atividade desregulada, hipoatividade ou não alteração. Tais resultados dependem das variáveis e dos hormônios estudados, do fluido coletado – plasma, urina, saliva, líquido cefalorraquidiano – do horário de coleta, do número de coletas, da análise estatística utilizada, do subtipo de doença depressiva, entre outros. Conclusão: Os resultados não apresentam consenso em relação à atividade do eixo HPA. Considerando as variáveis estudadas, o eixo HPA, na maioria das vezes, apresenta-se disfuncional na presença da depressão.

Social class and gender patterning of insomnia symptoms and psychiatric distress: a 20-year prospective cohort study

BACKGROUND

Psychiatric distress and insomnia symptoms exhibit similar patterning by gender and socioeconomic position. Prospective evidence indicates a bi-directional relationship between psychiatric distress and insomnia symptoms so similarities in social patterning may not be coincidental. Treatment for insomnia can also improve distress outcomes. We investigate the extent to which the prospective patterning of distress over 20 years is associated with insomnia symptoms over that period.

METHODS

999 respondents to the Twenty-07 Study had been followed for 20 years from approximately ages 36-57 (73.2% of the living baseline sample). Psychiatric distress was measured using the GHQ-12 at baseline and at 20-year follow-up. Gender and social class were ascertained at baseline. Insomnia symptoms were self-reported approximately every five years. Latent class analysis was used to classify patterns of insomnia symptoms over the 20 years. Structural Equation Models were used to assess how much of the social patterning of distress was associated with insomnia symptoms. Missing data was addressed with a combination of multiple-imputation and weighting.

RESULTS

Patterns of insomnia symptoms over 20 years were classified as either healthy, episodic, developing or chronic. Respondents from a manual social class were more likely to experience episodic, developing or chronic patterns than those from non-manual occupations but this was mostly explained by baseline psychiatric distress. People in manual occupations experiencing psychiatric distress however were particularly likely to experience chronic patterns of insomnia symptoms. Women were more likely to experience a developing pattern than men, independent of baseline distress. Psychiatric distress was more persistent over the 20 years for those in manual social classes and this effect disappeared when adjusting for insomnia symptoms. Irrespective of baseline symptoms, women, and especially those in a manual social class, were more likely than men to experience distress at age 57. This overall association for gender, but not the interaction with social class, was explained after adjusting for insomnia symptoms. Sensitivity analyses supported these findings.

CONCLUSIONS

Gender and socioeconomic inequalities in psychiatric distress are strongly associated with inequalities in insomnia symptoms. Treatment of insomnia or measures to promote healthier sleeping may therefore help alleviate inequalities in psychiatric distress.

Thyroid function within the normal range and the risk of depression: a population-based cohort study

CONTEXT

Overt hypo- and hyperthyroidism are associated with an increased risk of depression. Little is known about the effects of variation in thyroid function within the normal range on the risk of depression.

OBJECTIVE

The objective of the study was to examine the association between normal-range thyroid function and the risk of depression.

DESIGN, SETTING, AND PARTICIPANTS

This was a cohort study in 1503 Dutch men and women, aged 70.6 (7.3) (mean [SD]) years. At baseline, serum TSH, thyroperoxidase antibody levels, and depressive symptoms [Center for Epidemiologic Studies Depression Scale (CES-D)] were assessed. A CES-D of 16 or greater is indicative of a depressive disorder. During follow-up (mean 8.0 y), participants were continuously monitored for the occurrence of incident depressive syndromes (n = 156).

RESULTS

Cross-sectionally, persons in the lowest TSH tertile (0.3-1.0 mU/L) had more depressive symptoms [CES-D score (mean): 7.95 vs 6.63, P = .014] as well as an increased risk of a CES-D of 16 or greater [10.7% vs 5.0%, odds ratio (95% confidence interval) 2.22 (1.18-4.17)], compared with persons in the highest normal range TSH tertile (1.6-4.0 mU/L). In the prospective analyses, persons in the lowest TSH tertile who were depression free at baseline had a higher risk of incident depressive syndromes [12.3% vs 7.6%, odds ratio (95% confidence interval) 1.85 (1.10-3.11)]. Thyroid autoimmunity (thyroperoxidase antibody positivity) was not associated with CES-D scores or incident depressive syndromes.

CONCLUSIONS

Elderly persons with low-normal TSH levels have more concurrent depressive symptoms as well as a substantially increased risk of developing a depressive syndrome in the subsequent years. This study identifies low-normal TSH as an important risk factor for depression in the elderly.

Temporal relationships between depressive symptoms and white matter hyperintensities in older men and women

OBJECTIVE

Associations between vascular disease and depression in late life, including increased white matter hyperintensities (WMHs), have been reported. Whether depression is an etiology or a consequence of vascular disease is still unknown. We investigated the temporal relationship between depressive symptoms and WMHs in older men and women.

METHODS

We utilized data from 90 dementia-free older adults (39 women, 51 men), 57 years of age and older at baseline, from the neuroimaging substudy of the Baltimore Longitudinal Study of Aging. Participants were followed for up to 8 years. Ratings of white matter disease burden were available for the first, last, and at least one interim visit, and participants completed the Center for Epidemiologic Studies Depression Scale (CES-D) annually. Statistical models, performed separately in men and women, examined whether depressive symptoms predicted subsequent WMH ratings or WMHs predicted subsequent depressive symptoms.

RESULTS

The total CES-D score was not associated with WMHs in men or women. In men, the CES-D depressed mood subscale predicted accelerating longitudinal increases in WMHs at older ages, but WMHs did not predict subsequent depressive symptoms. In women, there were no significant associations between the CES-D depressed mood subscale and WMHs.

CONCLUSIONS

White matter disease may be a consequence of depressed mood in men but not in women. Intervention strategies for depression may slow the progression of white matter disease in older men. These results add to previous findings documenting sex differences in the correlates of depressive disorders in late life.

Sex differences of salivary cortisol secretion in patients with major depression

Depression is associated with increased cortisol secretion and occurs more often in women than in men. Thus, it has been hypothesized that differences in cortisol secretion might, in part, be responsible for the greater risk of developing depression in women. However, only few studies have examined sex differences in baseline cortisol secretion in depressed patients and healthy controls. We examined sex effects on cortisol secretion in 52 medication-free patients with major depression (37 women, 15 men, mean ± SD age 35 ± 11 years, Hamilton Depression Scale mean score 27 ± 5) and 50 healthy age- and sex-matched control subjects. Salivary cortisol concentrations were measured at 8:00, 12:00, 16:00, and 22:00 h. Repeated measures analysis of covariance revealed a group × sex interaction (p = 0.05). Post hoc tests revealed higher cortisol concentrations in depressed compared to healthy men [F(1;29) = 7.5, p = 0.01]. No differences were found between depressed and non-depressed women. Our results do not support the hypothesis that differences in cortisol secretion between depressed and non-depressed subjects are more pronounced in women than in men. Study characteristics and methods as well as sex-specific confounding variables such as menstrual cycle, menopause and the use of oral contraceptives may account for inconclusive results across studies.

The impact of gender on antidepressants

There is a large body of literature debating whether and how gender affects the metabolism, side-effect profile, and efficacy of antidepressants. Gender differences in antidepressant pharmacokinetics and efficacy profiles have been attributed to not only anatomic and physiological differences between the sexes, but also behavioral factors, comorbid disorders, and gender-specific conditions, such as pregnancy and menopause. Despite the large body of research on this topic, few definitive conclusions regarding effects of gender on antidepressant treatment exist, and much of this research is incomplete, contradictory, or not fully used to optimize the administration of antidepressants and the response to treatment. This chapter will review the latest research on gender-specific effects of antidepressant treatment, focusing on the overall, gender-related differences in efficacy, metabolism, and side-effect profile of antidepressants, and how these differences can be used to better optimize treatment of depression in a clinical setting.

Reduced sleep spindle activity in early-onset and elevated risk for depression

OBJECTIVE

Sleep disturbances are common in major depressive disorder (MDD), although polysomnographic (PSG) abnormalities are more prevalent in adults than in children and adolescents with MDD. Sleep spindle activity (SPA) is associated with neuroplasticity mechanisms during brain maturation and is more abundant in childhood and adolescence than in adulthood, and as such, may be a more sensitive measure of sleep alteration than PSG in early-onset depression. This study investigated SPA changes related to early-onset MDD, comparing individuals already ill with MDD and individuals at high-risk for MDD with healthy nondepressed controls.

METHOD

The study included 63 participants (8 to 15 years of age): 21 currently depressed individuals, 21 individuals at high risk for MDD based on positive family history of MDD, and 21 healthy control individuals with no personal or family history of psychiatric illness. All participants maintained a regular sleep/wake schedule for 5 days, followed by 2 nights in the laboratory. SPA was analyzed in Stage 2 of non-rapid eye movement sleep.

RESULTS

SPA differed significantly between groups, particularly in the late part of the night (F(2,62) = 7.3, p = .001). Although the difference was greatest between the MDD and healthy control groups, both the MDD (p = .0004) and at high-risk groups (p = .02) had significantly lower SPA compared with healthy controls. SPA deficit was more prominent in females than in males (F(5,62) = 5.19, p = .005).

CONCLUSIONS

Low SPA characterizes youths with MDD and those at high risk for MDD, particularly girls, suggesting that early-onset depression and risk for the MDD are associated with decreased neuroplasticity.

Estrogen, stress and the brain: progress toward unraveling gender discrepancies in major depressive disorder

Women are twice as likely as men to develop major depressive disorder (MDD) and, while the neurobiological factors underlying this discrepancy are yet to be identified, estrogen almost certainly plays a role. MDD can be precipitated or exacerbated by exposure to stress and there is substantial evidence to suggest that estrogen can interact with stress systems to produce unique stress effects in females. This review integrates current research in animal models regarding estrogen-stress interactions in three areas of the brain known to be relevant to MDD: the hippocampus, the amygdala and the prefrontal cortex. The results from these studies are discussed in the context of MDD, and their implications for future treatment of MDD in women are explored.

Estrogen prevents norepinephrine alpha-2a receptor reversal of stress-induced working memory impairment

Understanding effects of estrogen on the medial prefrontal cortex (PFC) may help to elucidate the increased prevalence of depression and post-traumatic stress disorder in women of ovarian cycling age. Estrogen replacement in ovariectomized (OVX) young rats amplifies the detrimental effects of stress on working memory (a PFC-mediated task), but the mechanisms by which this occurs have yet to be identified. In male rats, stimulation of norepinephrine alpha-2 adrenoceptors protects working memory from stress-induced impairments. However, this effect has not been studied in females, and has not been examined for sensitivity to estrogen. The current study asked whether OVX females with estrogen replacement (OVX+Est) and without replacement (OVX+Veh) responded differently to stimulation of alpha-2 adrenoceptors after administration of the benzodiazepine inverse agonist FG7142, a pharmacological stressor. The alpha-2 agonist, guanfacine, protected working memory from the impairing effects of FG7142 in OVX+Veh, but not in OVX+Est rats. Western Blot analysis for alpha-2 receptors was performed on PFC tissue from each group, but no changes in expression were found, indicating that the behavioral effects observed were likely not due to changes in receptor expression. These findings point to possible mechanisms by which estrogen may enhance the stress response, and hold implications for the gender discrepancy in the prevalence of stress-related mental illness.

Women and major depressive disorder: clinical perspectives on causal pathways

BACKGROUND AND AIMS

Epidemiological data on the prevalence of mood disorders demonstrate that major depressive disorder (MDD) is approximately twice as common in women as in men and that its first onset peaks during the reproductive years. We aimed to review key social, psychological, and biological factors that seem strongly implicated in the etiology of major depression and to focus on sex-specific aspects of depression, such as the role of a woman's reproductive life cycle in depressive symptomatology.

METHODS

A review of the literature, from 1965 to present, was conducted.

RESULTS

An integrated etiological model best explains gender and sex differences in depression. Social, psychological, and biological variables must be simultaneously taken into account. These vulnerabilities include (but are not limited to) gender-specific roles in society, life stress such as trauma, a tendency toward ruminative coping strategies, and the effects of sex hormones and genetic factors.

CONCLUSIONS

To effectively treat MDD in women and to prevent the recurrence of illness in vulnerable women, clinicians must understand the sex-specific aspects of mood disorders over the longitudinal course of women's reproductive lives. A biopsychosocial approach should, therefore, be the main focus of future research and practice, to eventually result in an integrated etiological model of depression in women. Based on the prevalence of MDD in women, timely screening, diagnosis, and intervention should be public health priorities.

Longitudinal study on poor sleep and life dissatisfaction in a nationwide cohort of twins

Life satisfaction and quality of sleep are important, related components of subjective well-being and general health. However, no earlier investigation is known to have tested the direction of the temporal relation between poor sleep and diminished life satisfaction, including simultaneous examination of shared genetic influences. These features were examined in the present study of a nationwide cohort of 18,631 same-sex Finnish twins with repeated measurements of life satisfaction, sleep quality, and several potential confounders within an interval of 6 years (1975 and 1981). Most individuals (59%) with new-onset life dissatisfaction had experienced suboptimal sleep at baseline. Poor sleep predicted a consistent pattern of life dissatisfaction (odds ratio = 2.1, 95% confidence interval: 1.7, 2.7 from logistic regression on individuals; odds ratio = 3.0, 95% confidence interval: 1.7, 5.3 from conditional logistic regression on twin pairs discordant for life dissatisfaction), whereas life dissatisfaction did not consistently predict poor sleep. There was substantial heritability for both traits, but their shared genetic component was relatively weak, as indicated by genetic correlations of 0.21 for men and 0.27 for women in a multivariate genetic model. This finding is consistent with the hypothesis that poor sleep may have direct effects on the brain, emotions, and mood.

Estrogen and comprehension of metaphoric speech in women suffering from schizophrenia: results of a double-blind, placebo-controlled trial

OBJECTIVE

The effects of estrogen on comprehension of metaphoric speech, word fluency, and verbal ability were investigated in women suffering from schizophrenia. The issue of estrogen-dependent neuropsychological performance could be highly relevant because women with schizophrenia frequently suffer from hypoestrogenism.

METHOD

A placebo-controlled, double-blind, crossover study using 17beta-estradiol for replacement therapy and as an adjunct to a naturalistic maintenance antipsychotic treatment was carried out over a period of 8 months. Nineteen women (mean age = 38.0 years, SD = 9.9 years) with schizophrenia were included in the study. Comprehension of metaphoric speech was measured by a lexical decision paradigm, word fluency, and verbal ability by a paper-and-pencil test.

RESULTS

Significant improvement was seen for the activation of metaphoric meaning during estrogen treatment (P = .013); in contrast, no difference was found for the activation of concrete meaning under this condition. Verbal ability and word fluency did not improve under estrogen replacement therapy either.

CONCLUSIONS

This is the very first study based on estrogen intervention instead of the physiological hormone changes to examine the estrogen effects on neuropsychological performance in women with schizophrenia. In addition, it is the first time that the effect of estrogen on metaphoric speech comprehension was investigated in this context. While in a previous study estrogen therapy as adjunct to a naturalistic maintenance treatment with antipsychotics did not show an effect on psychopathology measured by a rating scale, a significant effect of estrogen on the comprehension of metaphoric speech and/or concretism, a main feature of schizophrenic thought and language disturbance, was found in the present study. Because the improvement of formal thought disorders and language disturbances is crucial for social integration of patients with schizophrenia, the results may have implications for the treatment of these individuals.

A magnetic resonance imaging study of the entorhinal cortex in treatment-resistant depression

Despite a growing interest in this area, we continue to lack an understanding of the pathophysiology of depression and of treatment-resistant depression (TRD) in particular. The role of the medial temporal lobe, particularly the hippocampus, has been widely implicated in the aetiology of depression. However, related structures such as the entorhinal cortex have not been systematically examined. This research study aimed to examine possible abnormalities in the volume of the entorhinal cortex (ERC) in TRD patients. A group of 45 TRD patients and 30 healthy age- and sex-matched controls underwent magnetic resonance imaging (MRI). ERC volumes were manually traced from MRI data using ANALYZE software. An analysis of variance was conducted between subject groups and in the sexes separately while controlling for the effects of brain size via intracranial volume (ICV). Results revealed significant reductions in the volume of the left ERC of female patients. Although preliminary, our findings suggest that anatomical abnormalities in the ERC may confer vulnerability to treatment resistance. Confirmatory longitudinal studies are required to determine whether these abnormalities predate the onset of depression or are the result of a more chronic, treatment-resistant course of illness.

Completed suicide in childhood

Suicide in children and young adolescents up to 14 years of age has increased in many countries, warranting research and clinical awareness. International reported suicide rates per 100,000 in this young population vary between 3.1 and 0 (mean rate worldwide, approximately 0.6/100.000; male-female ratio, 2:1). Suicide occurs only in vulnerable children; this vulnerability begins with parental mood disorder and impulsive aggression, and family history of suicide. Childhood affective and disruptive disorders and abuse are the most often reported psychiatric risk factors. Suicide becomes increasingly common after puberty, most probably because of pubertal onset of depression and substance abuse, which substantially aggravate suicide risk. Biologic findings are scarce; however, serotonergic dysfunction is assumed. The most common precipitants are school and family problems and may include actual/anticipated transitions in these environments. Suicides in children and young adolescents up to 14 years of age often follow a brief period of stress. Cognitive immaturity/misjudgment, age-related impulsivity, and availability of suicide methods play an important role. Psychologic autopsy studies that focus on suicides in this age group are needed.

Urinary free cortisol levels among depressed men and women: differential relationships to age and symptom severity?

BACKGROUND

Preclinical and clinical models of depression suggest sex differences may be mediated at least in part, by differences in hormonal modulation of hypothalamic-pituitary-adrenal (HPA) axis activity. Unraveling the consequences of moderating influences from the effect of sexual dimorphism will be vital to elaborating models of pathophysiology.

METHODS

The current study investigated urinary free cortisol (UFC) among younger adults with mild to moderate major depressive disorder to clarify the relationship with potential demographic and clinical moderators.

RESULTS

Male patients had higher mean UFC levels than female patients. Moreover, significant interactions between age and severity were found among men, but not women. In contrast to prior findings, neither age nor severity effects on UFC levels were found among female patients.

LIMITATIONS

Conclusions from the current study are limited by the absence of cortisol data from matched controls. Thus it was not possible to disentangle sex differences in baseline physiology from that of pathophysiological differences tied specifically to depression.

CONCLUSIONS

Despite several methodological limitations, the interactions between sex and both age and severity in this large sample of depressed patients are suggestive of differential pathophysiology for regulation of UFC excretion, and could reflect a neuroprotective effect for estrogen among younger depressed women.

Sleep microarchitecture in childhood and adolescent depression: temporal coherence

Previous work has indicated that low temporal coherence of ultradian sleep EEG rhythms is characteristic of depressed patients and women in particular. It may also be evident in depressed children and adolescents, although most published studies are limited in sample size. The present study evaluated temporal coherence of sleep EEG rhythms in 173 children and adolescents 8-17 years of age, including 97 who met criteria for major depressive disorder (MDD) and were symptomatic but unmedicated at the time of study and 76 healthy controls. Temporal coherence of all-night sleep EEG rhythms was evaluated on the second of two nights in the laboratory. Data were coded for diagnostic group, gender and age and subjected to MANOVAs. Temporal coherence was significantly lower in adolescents with MDD, compared to healthy controls. Findings were most robust for coherence between left and right beta and between delta and beta in both hemispheres. Both gender and age strongly influenced between-group differences, with the lowest temporal coherence among MDD girls, even in those under 13 years of age. In conclusion, early onset depression is associated with a reduction in synchronization of sleep EEG rhythms that shows a differential maturational course in boys and girls.

Sex-specific association between bipolar affective disorder in women and GPR50, an X-linked orphan G protein-coupled receptor

GPR50 is an orphan G protein-coupled receptor (GPCR) located on Xq28, a region previously implicated in multiple genetic studies of bipolar affective disorder (BPAD). Allele frequencies of three polymorphisms in GPR50 were compared in case-control studies between subjects with BPAD (264), major depressive disorder (MDD) (226), or schizophrenia (SCZ) (263) and ethnically matched controls (562). Significant associations were found between an insertion/deletion polymorphism in exon 2 and both BPAD (P=0.0070), and MDD (P=0.011) with increased risk associated with the deletion variant (GPR50(Delta502-505)). When the analysis was restricted to female subjects, the associations with BPAD and MDD increased in significance (P=0.00023 and P=0.0064, respectively). Two other single-nucleotide polymorphisms (SNPs) tested within this gene showed associations between: the female MDD group and an SNP in exon 2 (P=0.0096); and female SCZ and an intronic SNP (P=0.0014). No association was detected in males with either MDD, BPAD or SCZ. These results suggest that GPR50(Delta502-505), or a variant in tight linkage disequilibrium with this polymorphism, is a sex-specific risk factor for susceptibility to bipolar disorder, and that other variants in the gene may be sex-specific risk factors in the development of schizophrenia.

Family history influences age of onset in bipolar I disorder in females but not in males

Age of onset (AO) has been proposed as a promising criterion by which to select homogeneous subgroups for the genetic analysis of bipolar disorder. This is the first study to investigate the effect of the interaction between gender and family history (FH)-type on AO in bipolar disorder. In accordance with the literature, no difference in AO was observed between females and males in our sample of 264 Romanian bipolar I probands. Cox regression, however, showed a strong influence of FH-type on AO (P = 0.006). This was due to a significant variation in AO according to the type of FH in females (P = 0.002) but not in males (P = 0.64). Female bipolar disorder patients with a negative FH (FH(-)) had a later AO than females with either a FH of bipolar and/or schizoaffective disorder (P = 0.001) or a FH of recurrent unipolar major depression only (P = 0.04). Females with FH(-) had a later AO than males with FH(-) (P = 0.03). No sex difference was observed for AO in the group with a FH of recurrent unipolar depression. In the group with a FH of bipolar and/or schizoaffective disorder, females had an earlier AO than males (P = 0.01). A trend for support was observed in an independent sample of 217 German bipolar I patients for an influence of FH-type on AO in females (P = 0.09) but not in males (P = 0.15). Female bipolar disorder patients with FH(-) had a later AO than females with either a FH of bipolar and/or schizoaffective disorder (P = 0.04) or a FH of recurrent unipolar major depression only (P = 0.05). Females with FH(-) had a later AO than males with FH(-) (P = 0.05). Other comparisons were statistically not significant, which may be due to limited sample size. Our findings emphasize that the interaction between gender and FH-type is a source of heterogeneity for AO in bipolar disorder.

Prevalence of mood symptoms and depressions during pregnancy: implications for clinical practice and research

A review of the literature demonstrates that the incidence of new mental disorders and their prevalence during pregnancy is similar to the 12-month incidence of mental disorders in women during other periods of their lives. The prevalence of severe mood, behavior, and cognitive symptoms during pregnancy is rather high. Severe mental symptoms during pregnancy have been reported to be associated with an increased rate of complications during pregnancy and delivery, preterm deliveries, low birth weight, a higher rate of postpartum depression, and a longer-term impact on the offspring's development. Several pre-pregnancy risk factors to develop dysphoric symptoms have been reported, but their utility for primiparous women with no previous history of mental disorders is unclear. The association of mental symptoms with general symptoms and biological changes during pregnancy is also unclear. Given the short- and long-term impact of dysphoric symptoms and stress during pregnancy on mother and child, efficacious, efficient, and safe prevention and treatment modalities are essential and achievable. Clarification of the nature and phenotyping of mental and general symptoms during pregnancy is an important step for the development of effective interventions.

Are there gender differences in objective and subjective sleep measures? A study of insomniacs and healthy controls

It is well known that insomnia is more frequent in women than in men throughout all age groups. In this respect insomnia resembles other psychiatric disorders that occur more frequently in women such as anxiety and depressive disorders. Since insomnia is frequently a symptom of anxiety and depression, it remains an open question whether the comorbidity with psychiatric disorders fully explains the gender differences in the prevalence of insomnia or whether gender influences sleep independently from psychiatric conditions. We analyzed sleep measures of patients diagnosed with a primary insomnia (n=86) and of an age- and sex-matched healthy control group (n=86) by polysomnography; additionally, subjective rating scales were available for 70 patients and 54 controls matched for mean age and sex ratio. Surprisingly, none of the sleep continuity measures (sleep duration, sleep efficiency, arousal index, and wake%), nor slow wave or REM sleep % showed significant gender differences in both insomniacs and healthy controls. Also, subjective estimates of sleep quality were comparable in both sexes. As expected, insomniacs strongly differed from the control group in all subjective measures of sleep. Polysomnography showed significantly reduced sleep duration and efficiency, increased arousal index, and slightly, but significantly, less REM sleep in the insomniacs as compared to the healthy controls. These studies indicate that gender seems to have, if any, relatively little influence on sleep per se. We hypothesize that the clear gender differences in the prevalence of insomnia are caused predominantly by gender differences in the prevalence of anxiety and depression. Primary insomnia may be, at least in a part of the cases, a subclinical or subthreshold form of anxiety or depression.

Chronic fatigue and sociodemographic characteristics as predictors of psychiatric disorders in a community-based sample

OBJECTIVES

To explore the roles of chronic fatigue and sociodemographic characteristics (eg, parental status, work status, socioeconomic status, sex, age, marital status, and ethnicity) as predictors of psychiatric disorders.

METHODS

A stratified random sample of 18,675 adults residing in diverse neighborhoods in Chicago completed a telephone-screening questionnaire. A control group without chronic fatigue (N = 74) and a group of individuals with chronic fatigue (N = 227) were identified and administered a semi-structured psychiatric interview. Stepwise logistic regression analyses predicting occurrence of current and lifetime psychiatric disorders according to chronic fatigue status and sociodemographics were conducted on this overall sample of 301 participants.

RESULTS

Chronic fatigue, low socioeconomic status, and unemployment were among significant predictors of overall Axis I psychiatric disorders. Chronic fatigue functioned as a predictor for mood and anxiety disorders (including posttraumatic stress disorder), but did not function as a predictor for somatoform disorders, substance abuse/dependence, and eating disorders. Low socioeconomic status and unemployment were significantly associated with current psychiatric disorder, and low socioeconomic status was also significantly associated with mood and anxiety disorders. Women were significantly more likely to experience mood disorder, and minorities (eg, African Americans, Latinos, and individuals of other ethnicity) were significantly more likely to report posttraumatic stress disorder.

CONCLUSIONS

Results support prior findings for increased rates of psychiatric disorder among individuals with chronic fatigue and highlight the roles of low socioeconomic status, unemployment, being a woman, and being classified as a minority in their association with certain psychiatric disorders.

Beyond women's health the new discipline of gender-specific medicine

At its best, women's health is not something to be developed as an isolated discipline. If instead biologic sex is used as an important variable in research protocols, studying and comparing men and women directly, the data prompt the formulation of questions that never otherwise would be asked. In answering those questions, one can fashion more accurate and complete models not only of human physiology, but also of the pathophysiology of disease.

Gender differences in unipolar depression: an update of epidemiological findings and possible explanations

OBJECTIVE

To give an update on epidemiological findings on sex differences in the prevalence of unipolar depression and putative risk factors.

MATERIAL AND METHODS

Systematic review of the literature.

RESULTS

Recent epidemiological research yields additional evidence for a female preponderance in unipolar depression, holding true across different cultural settings. Current explanations include artefacts, genetic, hormonal, psychological and psychosocial risk factors. Rather consistently, intrapsychic and psychosocial gender role related risk factors have been identified which may contribute to the higher depression risk in women. Gender role aspects are also reflected in endocrine stress reactions and possibly influence associated neuropsychological processes.

CONCLUSION

There is a need for more integrative models taking into account psychological, psychosocial, and macrosocial risk factors as well as their interactions, which also connect these factors with physiological and endocrine responses. Furthermore, it is conceivable that across the life span, as well as across cultural settings, individual risk factors will add with varying emphasis to the higher prevalence of depression in women.

State markers of depression in sleep EEG: dependency on drug and gender in patients treated with tianeptine or paroxetine

Tianeptine enhances while paroxetine inhibits serotonin reuptake into neurons; however, both show an antidepressive action. A subgroup of 38 depressed patients from a drug trial comparing the efficacy of tianeptine with that of paroxetine was studied with regard to their effects on sleep regulation, especially in relation to treatment response. We recorded sleep EEGs at day 7 and day 42 after the start of treatment with either compound, which allows measurement of changes due to the antidepressive medication in relation to the duration of treatment. Spectral analysis of the non-REM sleep EEG revealed a strong decline in the higher sigma frequency range (14-16 Hz) in male treatment responders independent of medication, whereas nonresponders did not show marked changes in this frequency range independent of gender. The patients receiving paroxetine showed less REM sleep and more intermittent wakefulness compared to the patients receiving tianeptine. REM density after 1 week of treatment was a predictor of treatment response in the whole sample. Psychopathological features with regard to the score in single items of the HAMD revealed predictive markers for response, some of which were opposite in the gender groups, especially those related to somatic anxiety. Changes in REM density were inversely correlated to the changes in HAMD in the paroxetine, but not the tianeptine, group. Our data suggest the importance of taking gender into account in the study of the biological effects of drugs. The study further points to the importance of the higher sigma frequency range in the sleep EEG of non-REM sleep and REM density as a marker of treatment response.

Temporal coherence in ultradian sleep EEG rhythms in a never-depressed, high-risk cohort of female adolescents

BACKGROUND

Previous work has indicated that low temporal coherence of ultradian sleep electroencephalographic rhythms is characteristic of depressed patients and of depressed women, in particular. It may also be evident in one quarter of those at high risk, based on a family history of depression.

METHODS

The present study evaluated temporal coherence of sleep electroencephalographic rhythms in 41 adolescent girls with a maternal history of depression (high risk) and 40 healthy controls (low risk). The entire sample was followed clinically every 6 months for 2 years.

RESULTS

Temporal coherence was significantly lower among the high-risk girls than in controls. Regression analyses predicted group from coherence values and correctly classified 70% of the high-risk group with a false-positive rate of 5% among controls. Moreover, 54% of the high-risk girls were identified with extreme low coherence. On clinical follow up, 14 girls showed depressive symptoms, 9 in the high-risk group (22.5%) and 5 controls (12.2%). Six met DSM-IV criteria for first-episode major depressive disorder, five high-risk and one control. Most importantly, 41% of those identified as having the most abnormal coherence values either showed symptoms of depression or met diagnostic criteria upon follow up.

CONCLUSIONS

Low temporal coherence is evident in adolescent girls at high risk for depression. The more abnormal the coherence, the greater the risk of a first episode of major depressive disorder within 2 years of sleep study, approximately 10 times greater than in controls.

Role of estrogen in the aetiology and treatment of mood disorders

Worldwide, the prevalence of depression in women is significantly greater than in men. Available data suggest that estrogen, or its absence, is strongly implicated in the regulation of mood and behaviour, as well as in the pathobiology of mood disorders. The multiple effects of estrogens and their complex interactions with the CNS and endocrine system have been well documented, although the specific, multifaceted role of estrogen in each dysphoric state has yet to be elucidated. Several facts suggest that estrogen plays a vital role in the precipitation and course of mood disorders in women. Gender differences in the prevalence of depression first appear after menarche, continue through reproductive age, and dissipate after perimenopause. Periods of hormonal fluctuations or estrogen instability (i.e. premenstrually, postpartum, perimenopausally) have been associated with increased vulnerability to depression among susceptible women. It is plausible that the phenotype of these depressions is distinguishable from those that are not associated with reproductive events or that occur in men. Based on current knowledge, estrogen treatment for affective disorders may be efficacious in two situations: (i) to stabilise and restore disrupted homeostasis - as occurs in premenstrual, postpartum or perimenopausal conditions; and (ii) to act as a psychomodulator during periods of decreased estrogen levels and increased vulnerability to dysphoric mood, as occurs in postmenopausal women. There is growing evidence suggesting that estrogen may be efficacious as a sole antidepressant for depressed perimenopausal women. It is still unclear whether estrogen is efficacious as an adjunct to selective serotonin reuptake inhibitors or as one of the paradigms to manage treatment-resistance depression in menopausal women, but such efficacy is plausible.

Depression as a spreading adjustment disorder of monoaminergic neurons: a case for primary implication of the locus coeruleus

A model for the pathophysiology of depression is discussed in the context of other existing theories. The classic monoamine theory of depression suggests that a deficit in monoamine neurotransmitters in the synaptic cleft is the primary cause of depression. More recent elaborations of the classic theory also implicitly include this postulate, other theories of depression frequently prefer to depart from the monoamine-based model altogether. We suggest that the primary defect emerges in the regulation of firing rates in brainstem monoaminergic neurons, which brings about a decrease in the tonic release of neurotransmitters in their projection areas, an increase in postsynaptic sensitivity, and concomitantly, exaggerated responses to acute increases in the presynaptic firing rate and transmitter release. It is proposed that the initial defect involves, in particular, the noradrenergic innervation from the locus coeruleus (LC). Dysregulation of the LC projection activities may lead in turn to dysregulation of serotonergic and dopaminergic neurotransmission. Failure of the LC function could explain the basic impairments in the processing of novel information, intensive processing of irrational beliefs, and anxiety. Concomitant impairments in the serotonergic neurotransmission may contribute to the mood changes and reduction in the mesotelencephalic dopaminergic activity to loss of motivation, and anhedonia. Dysregulation of CRF and other neuropeptides such as neuropeptide Y, galanin and substance P may reinforce the LC dysfunction and thus further weaken the adaptivity to stressful stimuli.

Gender differences in cocaine craving among non-treatment-seeking individuals with cocaine dependence

The purpose of this pilot study was to evaluate potential gender differences in cocaine craving among non-treatment seekers with cocaine dependence. We examined 10 female and 11 male individuals matched by demographic characteristics and severity of drug use; we used a multidimensional questionnaire that assesses various aspects of craving: (a) current intensity, (b) projected intensity, (c) resistance to use cocaine, (d) responsiveness to drug-related conditioned stimuli, and (e) imagined likelihood of use if in a setting with access to drugs. Other instruments utilized were the Hamilton Rating Scale for Depression and Addiction Severity Index. Female subjects had higher total craving scores (p < .05), with post hoc tests showing more present desire to use cocaine and responsivity to drug-conditioned stimuli, along with lower scores on the desire not to use cocaine. In exploratory analyses, we found greater depressive symptomatology (p = .02) and severity of family/social problems (p = .02) in females than their males counterparts. These results suggest that gender may influence different aspects of cocaine craving. As estrogen is purported to modulate craving-related dopaminergic systems, further studies will be needed to confirm these observed gender differences and to investigate their possible mechanisms, particularly estrogen-dopamine interactions and their effect on craving and mood.

EEG power, frequency, asymmetry and coherence in male depression

Quantitative electroencephalographic (EEG) power topography has served as a useful tool for investigating brain regional mechanisms underlying affective disorders. In an attempt to examine the role of gender and widen the scope of the measurement probes used in these investigations, the traditional power and inter-hemispheric power ratio indices were supplemented with intra-hemispheric power ratios, mean frequency and both inter and intra-hemispheric coherence indices, in the comparison of depressed male patients and healthy controls. Resting (eyes closed), vigilance controlled EEG recordings from 21 scalp sites were collected from 70 male, unmedicated, unipolar major depressive disorder outpatients and 23 normal control male subjects. Absolute and relative power, frequency, asymmetry and coherence measures derived from spectrally analyzed EEGs were subjected to univariate analyses for group comparisons as well as to discriminant function analysis to examine their utility as classification indices. Compared with controls, patients evidenced greater overall relative beta power and, at bilateral anterior regions, greater absolute beta power and faster mean total spectrum frequency. Inter-hemispheric alpha power asymmetry index differences were noted, with controls exhibiting relatively reduced left hemisphere activation, and widespread reduced delta, theta, alpha and beta coherence indices. Whereas intra-hemispheric theta power asymmetry reduction was exhibited in patients bilaterally at all regions, group differences with intra-hemispheric beta power asymmetry were unilateral, being restricted to the right hemisphere. Discriminant analysis correctly classified 91.3% of the patients and controls. Quantitative EEG measurements in male depression appear to describe a pattern of aberrant inter-hemispheric synchrony/asymmetry and a profile of frontal activation.

Gender differences in depression. Critical review

BACKGROUND

With few exceptions, the prevalence, incidence and morbidity risk of depressive disorders are higher in females than in males, beginning at mid-puberty and persisting through adult life.

AIMS

To review putative risk factors leading to gender differences in depressive disorders.

METHOD

A critical review of the literature, dealing separately with artefactual and genuine determinants of gender differences in depressive disorders.

RESULTS

Although artefactual determinants may enhance a female preponderance to some extent, gender differences in depressive disorders are genuine. At present, adverse experiences in childhood, depression and anxiety disorders in childhood and adolescence, sociocultural roles with related adverse experiences, and psychological attributes related to vulnerability to life events and coping skills are likely to be involved. Genetic and biological factors and poor social support, however, have few or no effects in the emergence of gender differences.

CONCLUSIONS

Determinants of gender differences in depressive disorders are far from being established and their combination into integrated aetiological models continues to be lacking.

Neuropeptide Y in male and female brains of Flinders Sensitive Line, a rat model of depression. Effects of electroconvulsive stimuli

Human and animal studies suggest that neuropeptide Y (NPY), a peptide co-localized and co-released with classical neurotransmitters, is involved in the pathogenesis of affective disorders. In addition, lithium, electroconvulsive treatments (ECT in humans and ECS in rodents) and antidepressants affect NPY in a specific temporal- and brain-region fashion. These results have been obtained on healthy male rats; females and/or "depressed" animals have essentially not been studied. Consequently, we studied brain NPY-like immunoreactivity (-LI) under basal conditions and following a series of ECS in both male and female Flinders Sensitive Line (FSL), an animal model of depression, and their controls, the Flinders Resistant Line (FRL) rats. Furthermore, we examined whether the oestrus cycle affects NPY-LI in these strains. Following sacrifice by focused microwave irradiation, the peptides were extracted from dissected brain regions and measured by radioimmunoassay. Hippocampal NPY-LI in both sexes was significantly lower in the "depressed" FSL compared to the control FRL. ECS increased NPY-LI in both male and female rats in both FSL and FRL strains in hippocampus, frontal cortex and occipital cortex. In the hypothalamus, the increase was found only in the FSL rats. In both FSL and control rats, the basal NPY-LI was lower in the hippocampus of female compared to male rats. NPY-LI did not vary during the different phases of the oestrus cycle. These results suggest that the gender differences are not due to NPY-LI variations during the oestrus. The results are consistent with our hypothesis that NPY plays a role in the pathophysiology of depressive disorders and provide further evidence that one of the modes of ECS action is to elevate NPY in the limbic system. Assumption that gender differences in NPY could explain increased rates of depression in women is speculative, but is in line with the findings in the present study.

The estimated rate of depressed mood in US adults: recent evidence for a peak in later life

OBJECTIVE

The main aim of this study is to add new evidence on the descriptive epidemiology of depressed mood, and to investigate suspected determinants for depressed mood in adulthood.

METHODS

The data are from a continuing survey of a nationally representative sample of adult household residents in the United States, conducted in 1995 and 1996, totaling 26,883 respondents. Multiple logistic regression procedures yielded estimated associations.

RESULTS

We found that an estimated 1.9% of adult females and 1.0% of adult males experience a spell of sustained depressed mood during a span of approximately 2 weeks duration (i.e. point prevalence). For most of these cases, this is not the first spell. Among women, the smoothed curve for the prevalence estimates shows a peak in the youngest age stratum and decreases across age strata before 60 years, and has a slight secondary peak thereafter. In contrast, for males, the prevalence estimates of depression show no peak in the older age strata. Evidence from logistic regression analyses supports the inference of this later life peak in frequency of depressed mood among women. These new findings add to a growing body of epidemiological evidence on age and depression, and provoke new questions about the possibly etiological relationships involving social structural characteristics of local neighborhoods in combination with individual-level risk factors that have received primary attention in recent psychiatric epidemiology.

CONCLUSIONS

These findings point to the need for further etiological research, including studies of relationships between social structural characteristics of local neighborhoods and the occurrence of spells of depressed mood, as well as clinical implications for depression mood in late life.

Imidazoline and alpha(2a)-adrenoceptor binding sites in postmenopausal women before and after estrogen replacement therapy

BACKGROUND

Platelet alpha(2A)-adrenoceptors (alpha(2A)AR) and imidazoline binding sites (subtype I(1)) have been proposed as peripheral markers of brain stem receptors that mediate sympathetic outflow and are reported to be elevated in major depression.

METHODS

In our study, p[(125)I]-iodoclonidine was used to assess platelet alpha(2A)AR and I(1) binding sites in healthy postmenopausal women (n = 34) compared with healthy women of reproductive age (n = 26). Receptor determinations were repeated in 19 postmenopausal women following 59-60 days of estrogen replacement therapy (ERT; 0.1 mg estradiol transdermal patches).

RESULTS

I(1) binding sites were twofold higher in platelets of postmenopausal women compared with women of reproduction age but were down-regulated (normalized) after 59-60 days of ERT. All other binding parameters, including platelet alpha(2A)AR density, were not different between groups nor were they changed after ERT. Platelet I(1) densities after 59-60 days of ERT were positively correlated with plasma luteinizing hormone concentrations.

CONCLUSIONS

It is suggested that increased imidazoline binding sites might be associated with mood and behavioral changes in postmenopausal women.