Role of family history and 5-HTTLPR polymorphism in female seasonal affective disorder patients with and without premenstrual dysphoric disorder

Psychological factors and premenstrual syndrome: A Spanish case-control study

Objective

To assess whether the psychological variables perceived stress, neuroticism and coping strategies, are associated with Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Syndrome (PMDD).

Design

Case-control study with incident cases using the Spanish public healthcare system.

Setting

3 major public hospitals and one family counseling and planning center.

Population

Women consulting for troubles related to menstruation and for other motives such as screening for uterine cancer, contraception counselling or desire for pregnancy.

Methods

Logistic regression.

Main outcome measures

Odds of PMS and PMDD.

Results

285 PMS and 285 age-matched controls, as well as 88 PMDD cases and 176 controls participated in the study. Medium and high levels of perceived stress were associated with an increase in the odds of PMS (Odds Ratio (OR) = 2.49; 95%CI: 1.41–4.39 and OR = 4.90; 95%CI: 2.70–8.89, respectively). For PMDD the results were: OR = 2.61; 95%CI: 1.35–5.05 and OR = 5.79; 95%CI: 2.63–12.76, respectively.

Subjects with medium and high levels of neuroticism were also at higher odds of suffering from PMS (OR = 2.53; 95%CI: 1.06–6.06 and OR = 8.05; 95%CI: 3.07–2.12, respectively). For PMDD, the results were OR = 3.70; 95%CI: 1.27–10.77 and 5.73: 95%CI: 1.96–16.77, respectively.

High levels in the large majority of coping strategies were also associated with increased odds of PMS and PMDD.

Conclusions

Psychological factors including perceived stress, neuroticism and coping strategies are strongly related to PMS/PMDD. This association is unlikely to be due to confounding or misclassification bias. A reverse causation process cannot be ruled out although its likelihood is remote.

Seasonality-resilient individuals downregulate their cerebral 5-HT transporter binding in winter - A longitudinal combined 11C-DASB and 11C-SB207145 PET study

We have recently shown that the emergence and severity of seasonal affective disorder (SAD) symptoms in the winter is associated with an increase in cerebral serotonin (5-HT) transporter (SERT) binding. Intriguingly, we also found that individuals resilient to SAD downregulate their cerebral SERT binding in the winter. In the present paper, we provide an analysis of the SERT- and 5-HT dynamics as indexed by 5-HT₄ receptor (5-HT4R) binding related to successful stress coping. We included 46 ¹¹C-DASB positron emission tomography (PET) scans (N = 23, 13 women, age: 26 ± 6 years) and 14 ¹¹C-SB207145 PET scans (7 participants, 3 women, age: 25 ± 3 years) from 23 SAD-resilient Danes. Data was collected longitudinally in summer and winter. We found that compared to the summer, raphe nuclei and global brain SERT binding decreased significantly in the winter (p_raphe = 0.003 and p_global = 0.003) and the two measures were positively correlated across seasons (summer: R² = 0.33, p = .004, winter: R² = 0.24, p = .018). A voxel-based analysis revealed prominent changes in SERT in clusters covering both angular gyri (0.0005 < p_corrected < 0.0016), prefrontal cortices (0.00087 < p_corrected < 0.0039) and the posterior temporal and adjacent occipital cortices (0.0001 < p_corrected < 0.0066). We did not observe changes in 5-HT4R binding, suggesting that 5-HT levels remained stable across seasons. We conclude that resilience to SAD is associated with a global downregulation of SERT levels in winter which serves to keep 5-HT levels across seasons.

Genetic Factors Affecting Seasonality, Mood, and the Circadian Clock

In healthy humans, seasonality has been documented in psychological variables, chronotype, sleep, feeding, metabolic and autonomic function, thermoregulation, neurotransmission, and hormonal response to stimulation, thus representing a relevant factor to account for, especially when considering the individual susceptibility to disease. Mood is largely recognized as one of the central aspects of human behavior influenced by seasonal variations. This historical notion, already mentioned in ancient medical reports, has been recently confirmed by fMRI findings, which showed that seasonality in human cognitive brain functions may influence affective control with annual variations. Thus, seasonality plays a major role in mood disorders, affecting psychopathology, and representing the behavioral correlate of a heightened sensitivity to factors influencing circannual rhythms in patients. Although the genetic basis of seasonality and seasonal affective disorder (SAD) has not been established so far, there is growing evidence that factors affecting the biological clock, such as gene polymorphisms of the core clock machinery and seasonal changes of the light-dark cycle, exert a marked influence on the behavior of patients affected by mood disorders. Here we review recent findings about the effects of individual gene variants on seasonality, mood, and psychopathological characteristics.

Reproductive Affective Disorders: a Review of the Genetic Evidence for Premenstrual Dysphoric Disorder and Postpartum Depression

PURPOSE OF REVIEW

The purpose of this study is to review and summarize the literature exploring the genetic basis for premenstrual dysphoric disorder (PMDD) and postpartum depression (PPD).

RECENT FINDINGS

There is more evidence for a genetic basis for PPD than for PMDD, but only when PPD is defined as beginning in the immediate postpartum time period. Familial, genome-wide linkage and association studies, and candidate gene studies, most in the past 10 years, have examined the genetic etiology of reproductive affective disorders, including PMDD and PPD. The most commonly studied genes include SERT, COMT, MAOA, BDNF, and ESR1 and 2. This qualitative review of the recent literature finds limited evidence so far for the genetic basis for PMDD, with both familial and candidate gene studies having negative or conflicting results. Evidence is stronger for the genetic basis for PPD, with positive associations found in family studies and in several genes associated with major depression as well as genes involved in estrogen signaling but only when PPD onset is shortly after delivery. Epigenetic biomarkers on genes responsive to estrogen have also been found to predict PPD. Our findings underscore the need for additional studies with larger samples, as well as the crucial importance of timing in the definition of PPD for genetic studies.

Premenstrual syndrome health-related quality of life and psychiatric comorbidity in a clinical adolescent sample: a cross-sectional study

OBJECTIVE

Adolescents who were admitted to the child and adolescent psychiatry clinic were compared with respect to the premenstrual symptom severity, psychiatric comorbidities and health related quality of life (HRQoL).

METHODS

The research group was identified using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version and Premenstrual Assessment Form. They completed the Pediatric Quality of Life Inventory (The PedsQL).

RESULTS

There were 55 adolescents who were eligible for the study and 89% of participants were diagnosed with at least one psychiatric disorder. The most common psychiatric diagnoses among the diagnosed cases were anxiety and major depressive disorders. Of all of the cases, 78.2% were diagnosed with premenstrual syndrome (PMS) and among those cases, 46.5% had mild, 34.8% had moderate and 18.6% had severe PMS. Most common PMS symptom was anger/irritability. HRQoL in the group with PMS was significantly lower than that of the adolescents without PMS. Moreover, HRQoL of adolescents with PMS was found to deteriorate with the increasing severity of PMS.

CONCLUSIONS

This study is of great importance since it demonstrated that PMS frequency is very high in a clinical adolescent population and negatively affects their HRQoL as similar to non-clinical adolescent population studies.

Affective temperaments and emotional traits are associated with a positive screening for premenstrual dysphoric disorder

OBJECTIVES

Preliminary evidence indicates that premenstrual dysphoric disorder (PMDD) may be frequently co-morbid with bipolar spectrum disorders. In addition, the manifestations of PMDD seem similar to a subthreshold depressive mixed state. Nevertheless, the associations between PMDD and affective temperaments and emotional traits have not been previously investigated.

METHODS

A consecutive sample of 514 drug-free Brazilian women (mean age: 22.8; SD=5.4years) took part in this cross-sectional study. Screening for PMDD was obtained with the validated Brazilian Portuguese version of the Premenstrual Symptoms Screening Tool (PSST). Affective temperaments and emotional dimensions were evaluated with the Affective and Emotional Composite Temperament Scale (AFECTS). In addition, socio-demographic and data on menstrual cycle were collected.

RESULTS

According to the PSST, 83 (16.1%) women screened positive for PMDD, while 216 (42.0%) women had no/mild premenstrual symptoms. The cyclothymic temperament was independently associated with PMDD (OR=4.57; 95% CI: 2.11-9.90), while the euthymic temperament had an independent association with a lower likelihood of a positive screening for PMDD (OR=0.28; 95% CI: 0.12-0.64). In addition, anger and sensitivity emerged as emotional dimensions significantly associated with PMDD.

CONCLUSIONS

A positive screening for PMDD was associated with a predominant cyclothymic temperament, while an euthymic temperament was associated with a lower likelihood for a positive screening for PMDD. These data deserve replication in prospective studies.

Seasonality and its distinct clinical correlates in bipolar II disorder

Seasonality is one of the key features in subjects with mood disorders and is involved in the multi-faceted nature of the clinical course. However, few studies have explored the clinical implications of seasonality in bipolar disorders. We examined the differential effects of seasonality on clinical variables between bipolar I and II disorder (BD I and II). Seasonality was assessed using the Seasonal Pattern Assessment Questionnaire (SPAQ) in 204 subjects with BD I and 308 with BD II. Following the comparisons between BD I and II groups, clinical characteristics related to seasonality were explored. Next, to predict the presence of seasonality, a logistic regression model was applied. The global seasonality score on the SPAQ was significantly higher in the BD II group than in the BD I group. In the BD I group, seasonality was associated with suicide attempt history. In the BD II group, on the other hand, seasonality was associated with female gender, depressive predominance, and premenstrual dysphoric disorder (PMDD). In the regression models, the presence of PMDD and female gender was significantly associated with seasonality in the BD II group. Our findings suggest that high seasonality tendency, a vulnerability maker for cyclic worsening, may contribute to a differential pattern of clinical characteristics in BD II.

Were there evolutionary advantages to premenstrual syndrome?

Premenstrual syndrome (PMS) affects up to 80% of women, often leading to significant personal, social and economic costs. When apparently maladaptive states are widespread, they sometimes confer a hidden advantage, or did so in our evolutionary past. We suggest that PMS had a selective advantage because it increased the chance that infertile pair bonds would dissolve, thus improving the reproductive outcomes of women in such partnerships. We confirm predictions arising from the hypothesis: PMS has high heritability; gene variants associated with PMS can be identified; animosity exhibited during PMS is preferentially directed at current partners; and behaviours exhibited during PMS may increase the chance of finding a new partner. Under this view, the prevalence of PMS might result from genes and behaviours that are adaptive in some societies, but are potentially less appropriate in modern cultures. Understanding this evolutionary mismatch might help depathologize PMS, and suggests solutions, including the choice to use cycle-stopping contraception.

On the application of light therapy in German-speaking countries

Many studies have investigated seasonal affective disorder (SAD; fall-winter-depression) and its treatment with light therapy (LT). However, to the best of our knowledge, no other study has investigated the usage of LT in Europe since 1994. Thus, we performed a survey in hospitals with adult psychiatric departments in German-speaking countries by questionnaire. First, a questionnaire was constructed, considering also recent developments in LT. This questionnaire was sent to all hospitals with adult psychiatric departments listed in the "Deutsches Krankenhaus Adressbuch," which contains hospitals from all German-speaking countries (Germany, Switzerland, and Austria). Non-responders were asked to answer the questionnaire by mail and by phone. We achieved a completion rate of 58%. Data show almost no relevant, non-artificial differences between countries as well as between type of hospital. LT is more frequently used in university and state hospitals than in other types of treatment facilities. Compared to 1994, the major findings are (1) a substantial increase in the use of LT from 13.0 to 69.8% with no differences between Germany, Austria, and Switzerland, (2) this increase is mostly due to treatment for various forms of depression and further possible applications are less often considered, (3) there is a shift in the usage of LT from monotherapy to combination of pharmacotherapy with LT as an adjunctive treatment, and (4) a north-south comparison showed no substantial differences. Considerably higher rates of usage of LT have been found compared to the last survey in German-speaking countries taking place in 1994. Usage almost tripled; however, possible indications for LT other than SAD and non-seasonal depression are not applied to full extent. Further efforts on the propagation of LT should therefore be undertaken, with the same rigorous studies as for pharmacotherapy.

SRD5A1 genotype frequency differences in women with mild versus severe premenstrual symptoms

The aims of this small pilot study were to explore the association between premenstrual symptom severity and two genes from the gamma-aminobutyric acid (GABA) pathway: steroid-5-alpha-reductase, alpha polypeptide 1 (SRD5A1) and gamma-aminobutyric acid receptor subunit alpha-4 (GABRA4). Saliva samples were obtained from a convenience sample of 19 Caucasian females ages 18-25 years, ten cases and nine controls. Deoxyribonucleic acid (DNA) was isolated, and genotyping performed on ten single nucleotide polymorphisms (SNPs). Ten percent of cases and 44% of controls had the cytosine/cytosine (C/C) genotype for the SRD5A1 SNP, rs501999 indicating that this genotype may protect women against severe premenstrual symptoms. Replication of this study using an adequately powered sample size is warranted.

Association of seasonality and premenstrual symptoms in bipolar I and bipolar II disorders

BACKGROUND

Although seasonal affective disorder and premenstrual syndrome (PMS) are frequently observed in mood disorders, little is known as to whether lifetime traits of seasonality and premenstrual distress are related to bipolar disorder independent of mood episodes. This study aimed at investigating these two cyclic traits with respect to bipolar I and II disorders as well as evaluating the association between them.

METHODS

Subjects included 61 female patients with bipolar I or II disorders and 122 healthy women. Seasonality and premenstrual symptoms were measured retrospectively on a lifetime basis using the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Premenstrual Symptoms Screening Tool (PSST).

RESULTS

Patients showed higher global seasonality scores on the SPAQ compared to the normal controls. Further, the patient-control difference was more prominent in cases of bipolar II disorder (p<0.0001) than in bipolar I disorder (p=0.001). The prevalence of moderate to severe PMS as indicated on the PSST was also significantly higher in bipolar II disorder patients (51.6%) as compared to controls (19.7%). A significant association between seasonality and PMS was observed in both patient and control groups.

CONCLUSIONS

The results suggested that female patients with bipolar disorder experience seasonal and premenstrual changes in mood and behavior regardless of their mood episodes, and traits of seasonality and PMS are associated with each other. A common biological mechanism of these two cyclic conditions may be involved in the development of the cyclicity of bipolar disorder.

Estrogen receptor alpha (ESR-1) associations with psychological traits in women with PMDD and controls

Premenstrual Dysphoric Disorder (PMDD) is a mood disorder affecting about 5% of women and is associated with substantial morbidity. Albeit inconsistently, PMDD is described as being characterized by heritable personality traits. Although PMDD is a heritable disorder, it is unclear whether any of the heritable susceptibility to PMDD resides in heritable personality traits. In groups of carefully characterized women with PMDD (n=68) and controls (n=56), we attempted to determine whether diagnosis-related traits could be confirmed, as well as to determine whether such traits were associated with SNPs in estrogen receptor alpha (ESR-1) that we previously demonstrated were associated with PMDD. We observed 7/25 traits to be significantly different in patients and controls and further showed that 11/12 significant associations observed between these 7 traits and 16 ESR-1 SNPs involved the intron 4 SNPs previously shown to be the locus of the association with PMDD. While several interactions between genotype and diagnosis were observed, the effect of genotype in most instances was in the same direction in patients and controls. These data demonstrate affective state-independent personality traits that distinguish patients with PMDD from controls and further support the relevance of ESR-1 polymorphic variants in the regulation of non-reproductive behaviors.

[Longitudinal study comparing depressive female patients with and without premenstrual exacerbation]

INTRODUCTION

The aim of this study was to evaluate whether there are any differences in the clinical features of depression, personality and the G factor among women with and without premenstrual exacerbation (PE) of depression.

MATERIAL AND METHODS

Ninety-nine outpatients diagnosed with major depression (DSM-IV) were interviewed twice. At baseline, the patients were not taking medication. The 74 patients who achieved remission (Hamilton rating scale for depression ≤7) after 16 weeks were evaluated again through the 16-personality factor (16-PF) questionnaire (5(th) edition) and the D48 (or Dominos) test.

RESULTS

No differences in clinical characteristics or prognosis were found between the two groups of women, except for the greater presence of seasonal features among women with PE. Women with PE also scored higher for self-control on the 16-PF and scored lower on the D48 (Domino) test. The logistic analysis showed that higher self-control scores increased the risk for PE in 51.3% of the sample, while higher scores on the D48 test decreased the risk in 8.6%.

CONCLUSIONS

There were no differences between the two groups in the clinical features or prognosis of depression, except for the higher rates of seasonal features in the PE group. In contrast, differences were found in personality traits and the D48 between the two groups.

Approach to premenstrual dysphoria for the mental health practitioner

As many as 7% of women experience significant social or occupational dysfunction as a result of severe premenstrual mood disturbance. Biological, psychological, and sociocultural factors are implicated in the cause of premenstrual dysphoric disorder, but the interaction between these factors remains to be elucidated. Mental health practitioners can aid women by providing diagnostic clarity and by initiating an integrated step-wise management approach.

Neuroticism-related personality traits are related to symptom severity in patients with premenstrual dysphoric disorder and to the serotonin transporter gene-linked polymorphism 5-HTTPLPR

Neuroticism has been linked to a functional polymorphism in the serotonin transporter gene (5-HTTLPR), with short-allele carriers being overrepresented among high-scorers on neuroticism. Studies evaluating neuroticism-related personality traits in relation to the 5-HTTLPR polymorphism among patients with premenstrual dysphoric disorder (PMDD) and are lacking. The primary aim of this study was to evaluate the relationship between PMDD and neuroticism-related personality traits, and secondly, to relate the personality trait scores of PMDD patients to experienced symptom severity and to the 5-HTTLPR short allele. Thirty PMDD patients and 55 asymptomatic healthy controls were included in the study. The Swedish Universities Scale of Personality was used to evaluate personality traits. Genotype analyses were available in 27 PMDD patients and 18 healthy controls. Women with PMDD displayed higher levels of neuroticism-related personality traits (psychic trait anxiety, somatic trait anxiety, embitterment, stress susceptibility and mistrust) than healthy controls, and these effects were most prominent in women with more severe luteal phase symptoms. Furthermore, PMDD patients with at least one copy of the short allele of the 5-HTTLPR polymorphism scored higher on psychic trait anxiety and lack of assertiveness than PMDD patients who were homozygous for the long allele. PMDD patients who suffer from more severe luteal phase symptoms also display increased scores of neuroticism-related personality traits in comparison with healthy controls. Within the group of PMDD patients, differences in certain personality trait scores are associated with the short allele of the 5-HTTLPR polymorphism.

Understanding and treating premenstrual dysphoric disorder: an update for the women's health practitioner

Up to 7% of women report premenstrual symptoms severe enough to impair daily function, and are said to suffer from premenstrual dysphoric disorder (PMDD). Although PMDD is predominately regarded as a biologically based condition, sociocultural factors, and particularly life stress, past sexual abuse, and cultural socialization, likely interact with hormonal changes. This integrative model has implications for etiology and treatment of PMDD.

Premenstrual mood symptoms: study of familiality and personality correlates in mood disorder pedigrees

We sought to determine whether premenstrual mood symptoms exhibit familial aggregation in bipolar disorder or major depression pedigrees. Two thousand eight hundred seventy-six women were interviewed with the Diagnostic Interview for Genetic Studies as part of either the NIMH Genetics Initiative Bipolar Disorder Collaborative study or the Genetics of Early Onset Major Depression (GenRED) study and asked whether they had experienced severe mood symptoms premenstrually. In families with two or more female siblings with bipolar disorder (BP) or major depressive disorder (MDD), we examined the odds of having premenstrual mood symptoms given one or more siblings with these symptoms. For the GenRED MDD sample we also assessed the impact of personality as measured by the NEO-FFI. Premenstrual mood symptoms did not exhibit familial aggregation in families with BP or MDD. We unexpectedly found an association between high NEO openness scores and premenstrual mood symptoms, but neither this factor, nor NEO neuroticism influenced evidence for familial aggregation of symptoms. Limitations include the retrospective interview, the lack of data on premenstrual dysphoric disorder, and the inability to control for factors such as medication use.

Temporomandibular disorder is associated with a serotonin transporter gene polymorphism in the Japanese population

Aims

Recent genetic studies have linked serotonin-related genetic polymorphisms with diverse disorders characterized by functional somatic symptoms, including chronic fatigue syndrome, irritable bowel syndrome, and premenstrual dysphoric disorder.

Methods

We investigated three serotonin-related genetic polymorphisms by screening genomic DNA of 36 temporomandibular disorder (TMD) patients.

Results

A significant increase of longer alleles (l and xl) was found in the TMD patients compared to the controls both by the genotype-wise and the allele-wise analyses (both p < 0.01 by χ² test and Fisher's exact test).

Conclusion

Genetic factors that involve the serotonergic system may play a role in the pathogenesis of TMD.

Update on the biology of seasonal affective disorder

The etiology and pathophysiology of seasonal affective disorder (SAD) has been linked to the seasons and to light since its first conceptualization. Aspects of SAD that make it particularly amenable to biological investigation include the predictable recurrent episodes, the rapid response to a nonpharmacologic treatment, the specific neurovegetative features, and the availability of rich animal models of seasonality. This paper reviews new findings for the major biological hypotheses for SAD, focusing on circadian rhythms, neurotransmitters, and molecular genetics. Integrative issues and future directions for the study of SAD, including the heuristic value of a dual-vulnerability hypothesis that conceptualizes seasonality as a dimensional construct and the importance of studying endophenotypes, will be discussed.

The stress system in the human brain in depression and neurodegeneration

Corticotropin-releasing hormone (CRH) plays a central role in the regulation of the hypothalamic-pituitary-adrenal (HPA)-axis, i.e., the final common pathway in the stress response. The action of CRH on ACTH release is strongly potentiated by vasopressin, that is co-produced in increasing amounts when the hypothalamic paraventricular neurons are chronically activated. Whereas vasopressin stimulates ACTH release in humans, oxytocin inhibits it. ACTH release results in the release of corticosteroids from the adrenal that, subsequently, through mineralocorticoid and glucocorticoid receptors, exert negative feedback on, among other things, the hippocampus, the pituitary and the hypothalamus. The most important glucocorticoid in humans is cortisol, present in higher levels in women than in men. During aging, the activation of the CRH neurons is modest compared to the extra activation observed in Alzheimer's disease (AD) and the even stronger increase in major depression. The HPA-axis is hyperactive in depression, due to genetic factors or due to aversive stimuli that may occur during early development or adult life. At least five interacting hypothalamic peptidergic systems are involved in the symptoms of major depression. Increased production of vasopressin in depression does not only occur in neurons that colocalize CRH, but also in neurons of the supraoptic nucleus (SON), which may lead to increased plasma levels of vasopressin, that have been related to an enhanced suicide risk. The increased activity of oxytocin neurons in the paraventricular nucleus (PVN) may be related to the eating disorders in depression. The suprachiasmatic nucleus (SCN), i.e., the biological clock of the brain, shows lower vasopressin production and a smaller circadian amplitude in depression, which may explain the sleeping problems in this disorder and may contribute to the strong CRH activation. The hypothalamo-pituitary thyroid (HPT)-axis is inhibited in depression. These hypothalamic peptidergic systems, i.e., the HPA-axis, the SCN, the SON and the HPT-axis, have many interactions with aminergic systems that are also implicated in depression. CRH neurons are strongly activated in depressed patients, and so is their HPA-axis, at all levels, but the individual variability is large. It is hypothesized that particularly a subgroup of CRH neurons that projects into the brain is activated in depression and induces the symptoms of this disorder. On the other hand, there is also a lot of evidence for a direct involvement of glucocorticoids in the etiology and symptoms of depression. Although there is a close association between cerebrospinal fluid (CSF) levels of CRH and alterations in the HPA-axis in depression, much of the CRH in CSF is likely to be derived from sources other than the PVN. Furthermore, a close interaction between the HPA-axis and the hypothalamic-pituitary-gonadal (HPG)-axis exists. Organizing effects during fetal life as well as activating effects of sex hormones on the HPA-axis have been reported. Such mechanisms may be a basis for the higher prevalence of mood disorders in women as compared to men. In addition, the stress system is affected by changing levels of sex hormones, as found, e.g., in the premenstrual period, ante- and postpartum, during the transition phase to the menopause and during the use of oral contraceptives. In depressed women, plasma levels of estrogen are usually lower and plasma levels of androgens are increased, while testosterone levels are decreased in depressed men. This is explained by the fact that both in depressed males and females the HPA-axis is increased in activity, parallel to a diminished HPG-axis, while the major source of androgens in women is the adrenal, whereas in men it is the testes. It is speculated, however, that in the etiology of depression the relative levels of sex hormones play a more important role than their absolute levels. Sex hormone replacement therapy indeed seems to improve mood in elderly people and AD patients. Studies of rats have shown that high levels of cumulative corticosteroid exposure and rather extreme chronic stress induce neuronal damage that selectively affects hippocampal structure. Studies performed under less extreme circumstances have so far provided conflicting data. The corticosteroid neurotoxicity hypothesis that evolved as a result of these initial observations is, however, not supported by clinical and experimental observations. In a few recent postmortem studies in patients treated with corticosteroids and patients who had been seriously and chronically depressed no indications for AD neuropathology, massive cell loss, or loss of plasticity could be found, while the incidence of apoptosis was extremely rare and only seen outside regions expected to be at risk for steroid overexposure. In addition, various recent experimental studies using good stereological methods failed to find massive cell loss in the hippocampus following exposure to stress or steroids, but rather showed adaptive and reversible changes in structural parameters after stress. Thus, the HPA-axis in AD is only moderately activated, possibly due to the initial (primary) hippocampal degeneration in this condition. There are no convincing arguments to presume a causal, primary role for cortisol in the pathogenesis of AD. Although cortisol and CRH may well be causally involved in the signs and symptoms of depression, there is so far no evidence for any major irreversible damage in the human hippocampus in this disorder.

Childhood inattention and dysphoria and adult obesity associated with the dopamine D4 receptor gene in overeating women with seasonal affective disorder

There is significant evidence that altered dopamine activity plays a role in seasonal affective disorder (SAD). The current study examined three separate genetic hypotheses for SAD related to the 7-repeat allele (7R) of the dopamine-4 receptor gene (DRD4), a variant associated with decreased affinity for dopamine. We examined the possible contribution of 7R to the overall expression of SAD, attention deficit disorder (ADD) comorbidity, and body weight regulation. As part of an ongoing genetic study of increased eating behavior and mood in female subjects, 108 women with winter SAD and carbohydrate craving/weight gain were administered the Wender-Utah Rating Scale to measure childhood ADD symptomatology, and a questionnaire to assess maximal lifetime body mass index (BMI). To test for an association between 7R and the categorical diagnosis of SAD, the transmission disequilibrium test (TDT) was used in a subsample of probands providing familial DNA. Standard parametric tests were used to compare childhood ADD symptoms and maximal lifetime BMI across the two genotypic groups defined by the presence or absence of 7R. The TDT found no initial evidence for an association between 7R and the categorical diagnosis of SAD. However, 7R carriers reported significantly greater inattention and dysphoria in childhood (p=0.01 and 0.001, respectively) and a higher maximal lifetime BMI (p=0.007) than did probands without this allele. Furthermore, excluding probands with extreme obesity (maximal BMI >40), a strong correlation was found linking childhood inattentive symptoms and maximal lifetime BMI (r=0.35, p=0.001). In overeating women with SAD, the 7R allele of DRD4 may be associated with a unique developmental trajectory characterized by attentional deficits and dysphoria in childhood and mild to moderate obesity in adulthood. This developmental course may reflect different manifestations of the same underlying vulnerability related to central dopamine dysfunction. Given the possibility of population stratification when studying genotype/phenotype relationships, future use of genomic controls and replication of our findings in other overeating and/or ADD populations are needed to confirm these initial results.

Altered depression-related behaviors and functional changes in the dorsal raphe nucleus of serotonin transporter-deficient mice

BACKGROUND

As a key regulator of serotonergic activity and target of many antidepressant treatments, the serotonin transporter (SERT) represents a potential mediator of anxiety- and depression-related behaviors. Using mice lacking the SERT (SERT KO), we examined the role of SERT function in anxiety- and depression-related behaviors and serotonergic neuron function.

METHODS

Serotonin transporter knockout mice were evaluated in paradigms designed to assess anxiety-, depression-, and stress-related behaviors. Dorsal raphe nucleus (DRN) function was assessed by quantitative serotonergic cell counting and extracellular electrical recording of neuronal firing properties.

RESULTS

Serotonin transporter knockout mice showed an increase in latency to feed in a novel situation, more immobility in a forced swim, increased escape latency in a shock escape paradigm, and decreased immobility in tail suspension. No differences in anxiety-related behaviors were seen in the open field and the elevated plus maze. Serotonin transporter knockout mice exhibit a 50% reduction in serotonergic cell number and a fourfold decrease in firing rate in the DRN.

CONCLUSIONS

Developmental loss of SERT produces altered behaviors in models of depression that are generally opposite to those produced by antidepressant treatment. The reduced serotonergic cell number and firing rate in the DRN of adult SERT KO mice suggest a mechanism for these altered behaviors.