Seasonal variation of mixed and pure episodes of bipolar disorder

A Systematic Review on the Impact of Seasonality on Severe Mental Illness Admissions: Does Seasonal Variation Affect Coercion?

Coercion in psychiatry is associated mainly with involuntary admissions. The purpose of this study was to investigate the associations between hospital admissions of patients suffering from affective and schizophrenic disorders and seasonality. A systematic literature search using PubMed, Scopus and Google Scholar was conducted, including studies with affective and schizophrenia disorder admissions, published from October 1992 to August 2020. A total of 31 studies were included in the review. Four broad severe mental illness admission categories were identified regarding seasonality: affective disorders, schizophrenia disorders, involuntary admission affective disorders and involuntary admission schizophrenia disorders. There was clear and strong evidence for spring and summer peaks for severe mental illness admissions; data provided for age, gender and involuntary admissions was limited. Seasonality may have a significant effect on the onset and exacerbation of psychopathology of severe mental illness and should be considered as a risk factor in psychiatric admissions, violence and the risk of mental health coercion. A better understanding of the impact of seasonality on severe mental illness will help professionals to provide the best practices in mental health services in order to reduce and prevent psychiatric hospitalizations (especially involuntary admissions) resulting in further coercive measures.

Seasonality of brain function: role in psychiatric disorders

Seasonality patterns are reported in various psychiatric disorders. The current paper summarizes findings on brain adaptations associated with seasonal changes, factors that contribute to individual differences and their implications for psychiatric disorders. Changes in circadian rhythms are likely to prominently mediate these seasonal effects since light strongly entrains the internal clock modifying brain function. Inability of circadian rhythms to accommodate to seasonal changes might increase the risk for mood and behavior problems as well as worse clinical outcomes in psychiatric disorders. Understanding the mechanisms that account for inter-individual variations in seasonality is relevant to the development of individualized prevention and treatment for psychiatric disorders. Despite promising findings, seasonal effects are still understudied and only controlled as a covariate in most brain research. Rigorous neuroimaging studies with thoughtful experimental designs, powered sample sizes and high temporal resolution alongside deep characterization of the environment are needed to better understand the seasonal adaptions of the human brain as a function of age, sex, and geographic latitude and to investigate the mechanisms underlying the alterations in seasonal adaptation in psychiatric disorders.

Investigating the association between temperature and hospital admissions for major psychiatric diseases: A study in Greece

Evidence has emerged regarding the role of seasonality and several meteorological parameters on bipolar disorder, schizophrenia and depression. We investigated the relationship between ambient and apparent temperature and hospital admissions of major psychiatric diseases in a psychiatric clinic of a General Hospital situated in Northern Greece during 2013-19. Temperature data was provided by the National Observatory of Athens and diagnosis for psychotic, schizophrenic, manic and bipolar and unipolar depression were retrieved from medical records. A total of 783 admissions were recorded. Poisson regression models adjusted for time trends were applied to analyze the impact of temperature on monthly admissions. A summer peak was observed for the bipolar disorder, irrespectively of substance/alcohol use status. Seasonality emerged also for psychotic and schizophrenic patients with a through in winter. An increase of 1 °C in either ambient or apparent temperature was associated with an increase 1-2% in the monthly admissions in most outcomes under investigation. Alcohol and drug abuse did not modify this effect. Although our results indicate effects of temperature on psychiatric admissions, they are not consistent across subgroups populations and need to be replicated by other methodologically superior studies.

The association between ozone and fine particles and mental health-related emergency department visits in California, 2005-2013

Recent studies suggest that air pollutant exposure may increase the incidence of mental health conditions, however research is limited. We examined the association between ozone (O3) and fine particles (PM2.5) and emergency department (ED) visits related to mental health outcomes, including psychosis, neurosis, neurotic/stress, substance use, mood/affective, depression, bipolar, schizotypal/delusional, schizophrenia, self-harm/suicide, and homicide/inflicted injury, from 2005 through 2013 in California. Air monitoring data were provided by the U.S. EPA's Air Quality System Data Mart and ED data were provided by the California Office of Statewide Health Planning and Development. We used the time-series method with a quasi-Poisson regression, controlling for apparent temperature, day of the week, holidays, and seasonal/long-term trends. Per 10 parts per billion increase, we observed significant cumulative 7-day associations between O3 and all mental health [0.64%, 95% confidence interval (CI): 0.21, 1.07], depression [1.87%, 95% CI: 0.62, 3.15], self-harm/suicide [1.43%, 95% CI: 0.35, 2.51], and bipolar [2.83%, 95% CI: 1.53, 4.15]. We observed 30-day lag associations between O3 and neurotic disorder [1.22%, 95% CI: 0.48, 1.97] and homicide/inflicted injury [2.01%, 95% CI: 1.00, 3.02]. Same-day mean PM2.5 was associated with a 0.42% [95% CI: 0.14, 0.70] increase in all mental health, 1.15% [95% CI: 0.62, 1.69] increase in homicide/inflicted injury, and a 0.57% [95% CI: 0.22, 0.92] increase in neurotic disorders per 10 μg/m3 increase. Other outcomes not listed here were not statistically significant for O3 or PM2.5. Risk varied by age group and was generally greater for females, Asians, and Hispanics. We also observed seasonal variation for outcomes including but not limited to depression, bipolar, schizophrenia, self-harm/suicide, and homicide/inflicted injury. Ambient O3 or PM2.5 may increase the risk of mental health illness, though underlying biological mechanisms remain poorly understood. Findings warrant further investigation to better understand the impacts of air pollutant exposure among vulnerable groups.

Seasonality in schizophrenia-An analysis of a nationwide registry with 110,735 hospital admissions

Background.

Seasonal patterns in hospitalizations have been observed in various psychiatric disorders, however, it is unclear whether they also exist in schizophrenia. Previous studies found mixed results and those reporting the presence of seasonality differ regarding the characteristics of these patterns. Further, they are inconclusive whether sex is an influencing factor. The aim of this study was therefore to examine if seasonal patterns in hospitalizations can be found in schizophrenia, with special regard to a possible influence of sex, by using a large national dataset.

Methods.

Data on all hospital admissions within Austria due to schizophrenia (F20.0–F20.6) for the time period of 2003–2016 were included. Age standardized monthly variation of hospitalization for women and men was analyzed and the level of significance adjusted for multiple testing.

Results.

The database comprised of 110,735 admissions (59.6% men). Significant seasonal variations were found in the total sample with hospitalization peaks in January and June and a trough in December (p < 0.0001). No significant difference in these patterns was found between women and men with schizophrenia (p < 0.0001).

Conclusion.

Our study shows that schizophrenia-related hospitalizations follow a seasonal pattern in both men and women. The distribution of peaks might be influenced by photoperiod changes which trigger worsening of symptoms and lead to exacerbations in schizophrenia. Further research is necessary to identify underlying factors influencing seasonal patterns and to assess whether a subgroup of patients with schizophrenia is especially vulnerable to the impact of seasonal variations.

Using Chronobiological Phenotypes to Address Heterogeneity in Bipolar Disorder

Bipolar disorder (BD) is a neuropsychiatric mood disorder characterized by recurrent episodes of mania and depression in addition to disruptions in sleep, energy, appetite, and cognitive functions-rhythmic behaviors that typically change on daily cycles. BD symptoms can also be provoked by seasonal changes, sleep, and/or circadian disruption, indicating that chronobiological factors linked to the circadian clock may be a common feature in the disorder. Research indicates that BD exists on a clinical spectrum, with distinct subtypes often intersecting with other psychiatric disorders. This heterogeneity has been a major challenge to BD research and contributes to problems in diagnostic stability and treatment outcomes. To address this heterogeneity, we propose that chronobiologically related biomarkers could be useful in classifying BD into objectively measurable phenotypes to establish better diagnoses, inform treatments, and perhaps lead to better clinical outcomes. Presently, we review the biological basis of circadian time keeping in humans, discuss the links of BD to the circadian clock, and pre-sent recent studies that evaluated chronobiological measures as a basis for establishing BD phenotypes. We conclude that chronobiology may inform future research using other novel techniques such as genomics, cell biology, and advanced behavioral analyses to establish new and more biologically based BD phenotypes.

Pharmacological Manipulation of the Circadian Clock: A Possible Approach to the Management of Bipolar Disorder

Bipolar disorder (BD) is a mood disorder with genetic and neurobiological underpinnings, characterized primarily by recurrent episodes of mania and depression, with notable disruptions in rhythmic behaviors such as sleep, energy, appetite and attention. The chronobiological links to BD are further supported by the effectiveness of various treatment modalities such as bright light, circadian phase advance, and mood-stabilizing drugs such as lithium that have effects on the circadian clock. Over the past 30 years, the neurobiology of the circadian clock has been exquisitely described and there now exists a detailed knowledge of key signaling pathways, neurotransmitters and signaling mechanisms that regulate various dimensions of circadian clock function. With this new wealth of information, it is becoming increasingly plausible that new drugs for BD could be made by targeting molecular elements of the circadian clock. However, circadian rhythms are multidimensional and complex, involving unique, time-dependent factors that are not typically considered in drug development. We review the organization of the circadian clock in the central nervous system and briefly summarize data implicating the circadian clock in BD. We then consider some of the unique aspects of the circadian clock as a drug target in BD, discuss key methodological considerations and evaluate some of the candidate clock pathways and systems that could serve as potential targets for novel mood stabilizers. We expect this work will serve as a roadmap to facilitate the development of compounds acting on the circadian clock for the treatment of BD.

Seasonality in bipolar disorder: Effect of sex and age

BACKGROUND

Mood episodes in bipolar disorder (BD) are reported to exhibit a seasonal pattern (SP). However, it is unclear whether this pattern is influenced by a patient's sex and age.

METHODS

In this nationwide registry study, we examined all inpatient treatments due to a manic (F31.0-2), depressive (F31.3-5) or mixed (F31.6) BD-episode in Austria for 2001-2014. Calculations were based on directly age-standardized rates and seasonality was analyzed on a monthly basis.

RESULTS

The database comprised 60,607 admissions (35.8% men). SP were shown for women during manic (summer-autumn), depressive (winter) and mixed (summer) episodes, for men only during manic (summer) episodes. However, no significant sex differences (manic p = 0.101, depressive p = 0.295, mixed p = 0.622 episode) were found. Women at young age (15-35 years) seemed to be more vulnerable to a SP in manic and mixed episodes.

LIMITATIONS

Only aggregated patient data of inpatient treatments and no single case histories were available.

CONCLUSIONS

In this nationwide registry study, a distinct SP could be shown for manic episodes in men and women, as well as a SP for depressive and mixed episodes in women. As no significant difference in any BD-subgroup could be observed, the effect of sex on the SP seems to be small, if existing at all. However, when taking age into account, we observed a higher likelihood for a SP in young women. Single case studies with information on possible further influencing factors (e.g. medication use) might help to clarify the impact of sex and age on SP in more detail.

Relationship between photoperiod and hospital admissions for mania in New South Wales, Australia

BACKGROUND

Causes for a seasonal impact on admissions for mania remain to be clarified. We examined the impact of photoperiod, rate of change of photoperiod and hours of sunshine on admissions over an extended period.

METHODS

Monthly admission data to NSW psychiatric hospitals for more than twenty thousand patients admitted for mania over a fifteen-year period were correlated with photoperiod and sunshine changes.

RESULTS

While the peak in admissions occurred in spring, the shift in admissions being under-represented to being precipitously over-represented corresponded with the photoperiod commencing to increase in winter (i.e. July). Analyses identified rate of change in photoperiod as somewhat more influential than change in photoperiod and with hours of sunshine not making a distinctive contribution. Immediate and delayed impacts of rate of change as well as change in photoperiod across the whole year accounted for a distinctive 20% of the variance in hospital admissions.

LIMITATIONS

Validity of mania diagnoses cannot be established from the data set, admission data were obtained from across the state while meteorological data were obtained from the capital city, lag periods between onset of a mania and hospitalization (while identified) would impact on associations, social factors were not included and study associations do not imply causality.

CONCLUSIONS

The lack of a strong year-long correlation may reflect photoperiod changes being only a weak causal factor or that its influence may be through a strong impact phase after the winter solstice and with the spring peaking of admissions reflecting secondary photoperiod or other influences.

Seasonal variations in hospital admissions for mania: Examining for associations with weather variables over time

BACKGROUND

Bipolar disorder is characterized by a seasonal pattern with emerging evidence that weather conditions may trigger symptoms. Thus, our aims were to investigate if year-to-year variations in admissions with mania correlated with year-to-year variations in key meteorological variables, if there was a secular trend in light of climate change and if gender or admission status influenced the seasonal pattern.

METHODS

We undertook a Danish register-based nationwide historical cohort study. We included all adults hospitalized to psychiatric care from 1995 to 2012 with mania using the Danish Psychiatric Central Research Register. The Danish Meteorological Institute provided the meteorological variables. The association between weather and admissions was tested using linear regression.

RESULTS

Our database comprised 24,313 admissions with mania. There was a seasonal pattern with admission rates peaking in summer. Higher admission rates were associated with more sunshine, more ultraviolet radiation, higher temperature and less snow but were unassociated with rainfall. We did not find a secular trend in the seasonal pattern. Finally, neither gender nor admission status impacted on the overall seasonal pattern of admissions with mania.

LIMITATIONS

Only patients in psychiatric care were included. We could not subdivide by type of bipolar disorder.

CONCLUSION

This cohort study based on more than 24,000 admissions identified a distinct seasonal pattern in hospital admissions for those with mania. We found no secular trend. This could indicate that the climate change is not impacting on seasonal patterns, that there is no link between the proposed variables or that change is currently not sufficiently distinctive.

Childhood disintegrative disorder with seasonal total mutism: A rare clinical presentation

Childhood disintegrative disorder (CDD) is a rare autistic-like clinical condition with unknown etiology, in that previously acquired age-appropriate language, social and adaptive abilities deteriorate significantly in 2-10-year-old healthy children, although physical and neurological evaluations display no observable abnormality. Our case is a 22-year-old female born of a consanguineous marriage, with the appearance of CDD symptoms in her fifth year of age following normal mental and physical development during her initial four years of life. Without any precipitating factor, she gradually lost her language abilities, social relational skills, affectionate behavior, adaptive capacities, peer play and meaningful interest in her surrounding, friends and family members over a period of 4 years, reaching a plateau in her ninth year of age. The unique special clinical symptom in this case is a seasonal total mutism, which after the beginning of her CDD symptoms is revealing every year covering the spring. As no additional physical or psychological change accompanies her total seasonal speech loss, it cannot be attributed to any mental condition known as having a seasonal pattern. Because in the literature CDD is presented mostly as case reports with lacking of advanced research data, describing any new case is recommended to improve the knowledge about this rare condition, especially if it displays some new unusual signs, not reported till now.

Identification of circadian gene variants in bipolar disorder in Latino populations

BACKGROUND

Variations in circadian genes can impact biological rhythms. Given the rhythm disturbances that characterize bipolar disorder (BD), genes encoding components of molecular clocks are good candidate genes for the illness.

METHODS

A family based association analysis of circadian gene single nucleotide polymorphisms (SNPs) and BD was conducted in Latino pedigrees. 884 individuals from 207 pedigrees (473BP phenotype and 411 unaffected family members) were genotyped. Family based single marker association testing was performed. Ancestral haplotypes (SNPs found to be in strong LD defined using confidence intervals) were also tested for association with BD.

RESULTS

Multiple suggestive associations between circadian gene SNPs and BD were noted. These included CSNK1E (rs1534891, p=0.00689), ARNTL (rs3789327, p=0.021172), CSNK1D (rs4510078, p=0.022801), CLOCK (rs17777927, p=0.031664). Individually, none of the SNPs were significantly associated with BD after correction for multiple testing. However, a 4-locus CSNK1E haplotype encompassing the rs1534891 SNP (Z-score=2.685, permuted p=0.0076) and a 3-locus haplotype in ARNTL (Z-score=3.269, permuted p=0.0011) showed a significant association with BD.

LIMITATIONS

Larger samples are required to confirm these findings and assess the relationship between circadian gene SNPs and BD in Latinos.

CONCLUSIONS

The results suggest that ARNTL and CSKN1E variants may be associated with BD. Further studies are warranted to assess the relationships between these genes and BD in Latino populations.

Psychiatric hospitalizations for affective disorders in Warsaw, Poland: Effect of season and intensity of sunlight

The purpose of this study was to assess any associations between the number of hospitalizations for affective disorders, seasons of the year and the intensity of sunlight in Poland, a country with a very changeable climate and significant seasonal fluctuations. We analyzed 2837 admissions with affective disorders hospitalized in the Institute of Psychiatry and Neurology in Warsaw, between 2002 and 2010 (mania, n=380, mixed episode, n=131, bipolar depression, n=736, recurrent depression, n=681, single depressive episode, n=909). For each diagnostic group admission time series were created and categorized into subgroups according to sex and age, and these were analyzed by means of the Autoregressive Integrated Moving Average (ARIMA) method. Regression models and correlations were used to assess the influence of the intensity of sunlight on the number of hospitalizations. Most mania admissions were noted in spring/summer months and in midwinter, mixed episode-late spring and winter, and depression (bipolar, recurrent and single depressive episode)-spring and autumn months. The association between frequency of admissions and monthly hours of sunshine was observed in some age and sex subgroups of patients with bipolar disorder and single depressive episode. The results support the seasonality of admissions of patients with affective disorders.

Seasonality of Admissions for Mania: Results From a General Hospital Psychiatric Unit in Pondicherry, India

INTRODUCTION

Bipolar disorder is affected by variables that modulate circadian rhythm, including seasonal variations. There is evidence of a seasonal pattern of admissions of mania in various geographical settings, though its timing varies by region and climate. Variables such as age and gender have been shown to affect seasonality in some studies.

METHODOLOGY

Data on monthly admission patterns for mania at a general hospital psychiatry unit in Pondicherry, India, were collected for 4 years (2010-2013) and analyzed for seasonality and seasonal peaks. The effects of age and gender were analyzed separately.

RESULTS

There was overall evidence of a seasonal pattern of admissions for mania (P < .01, Friedman test for seasonality), with a peak beginning during the rainy season and ending before summer (P < .0.1, Ratchet circular scan test). Male sex (P < .005, Ratchet circular scan test) and age > 25 years (P < .005, Ratchet circular scan test) were specifically associated with this seasonal peak.

DISCUSSION

The effect of seasons on mania is complex and is modulated by a variety of variables. Our study is consistent with earlier research findings: a greater degree of seasonality for mania in men. It is possible that climatic and individual variables interact to determine seasonal patterns in bipolar disorder in a given setting.

Genetics and epigenetics of circadian rhythms and their potential roles in neuropsychiatric disorders

Circadian rhythm alterations have been implicated in multiple neuropsychiatric disorders, particularly those of sleep, addiction, anxiety, and mood. Circadian rhythms are known to be maintained by a set of classic clock genes that form complex mutual and self-regulatory loops. While many other genes showing rhythmic expression have been identified by genome-wide studies, their roles in circadian regulation remain largely unknown. In attempts to directly connect circadian rhythms with neuropsychiatric disorders, genetic studies have identified gene mutations associated with several rare sleep disorders or sleep-related traits. Other than that, genetic studies of circadian genes in psychiatric disorders have had limited success. As an important mediator of environmental factors and regulators of circadian rhythms, the epigenetic system may hold the key to the etiology or pathology of psychiatric disorders, their subtypes or endophenotypes. Epigenomic regulation of the circadian system and the related changes have not been thoroughly explored in the context of neuropsychiatric disorders. We argue for systematic investigation of the circadian system, particularly epigenetic regulation, and its involvement in neuropsychiatric disorders to improve our understanding of human behavior and disease etiology.

Seasonality and bipolar disorder: a systematic review, from admission rates to seasonality of symptoms

INTRODUCTION

Bipolar disorder (BD) is a severe mental disorder affecting 1-4% of the population worldwide. It is characterized by periods of (hypo)manic and depressive episodes. Seasonal patterns (SP) may be observed in admission rates, mood relapses and symptom fluctuations.

METHODS

We conducted a systematic review of seasonality in BD, classifying studies based on seasonal admission rates to seasonality of symptoms assessments.

RESULTS

Fifty-one papers were identified of which 32 addressed hospitalization rates by season, 6 addressed categorical diagnoses, and 13 explored symptom dimensions. Seasonal peaks for different BD mood episodes are observed worldwide and widely replicated. Manic episodes peak during spring/summer and, to a lesser extent, in autumn, depressive episodes peak in early winter and, to a lesser extent, summer, and mixed episodes peak in early spring or mid/late summer. There was a high frequency of SP for manic episodes (15%) and depressive episodes (25%), the latter being associated with a more complex clinical profile (BD II subtype, comorbid eating disorders, more relapses and rapid cycling). Finally, there was evidence for greater seasonal fluctuations in mood and behavior in individuals with BD than in those with unipolar depression or 'healthy' controls.

LIMITATIONS

Sample size, gender distribution, methodological quality and sophistication of the analytical approaches employed varied considerably.

CONCLUSIONS

There is evidence of seasonality in BD, with emerging evidence that climatic conditions may trigger BD symptoms or episodes. A better understanding of the underlying mechanisms would facilitate the development of personalized chronobiological therapeutic and preventive strategies.

[Bipolar disorder: inter-episode symptoms]

The importance of inter-episode symptoms in bipolar disorder can be traced back to the middle of the 19th century, at a time when the two fathers of the concept in France, Falret and Baillarger were opposed on the issue as to whether the presence of free intervals between the episodes had to be part or not of the disease's definition. Modern studies have reported rates between 50 and 68% for those symptoms which refer to subsyndromal manifestations present between affective episodes but that do not meet the required criteria for episodes definition. These manifestations comprise residual symptoms, prodromes, axis I comorbid psychiatric disorders, side effects of treatment, temperamental features, and comorbidity with personality disorders. Inter- episodes symptoms represent a risk factor for the occurrence of relapses and recurrences and are usually associated with impairments in functioning in almost all domains of psychosocial and family life. As they are easy to miss, it is important in clinical practice, to draw the attention of clinicians, patients and relatives to the role they have in the course of the illness. As far as their management, it may be crucial to achieve a full remission of the episodes, using adequate dosages of psychotropic drugs. Residual symptoms, prodromes as well as other inter-episode symptoms may respond to strategies based on cognitive-behaviour therapy, and/or psychoeducation.

[Mixed states]

The issue of mixed states has an important place in the debate on psychiatric nosography since the end of 19th century. The current definition of mixed states according to the DSM- IV, as a thymic episode of bipolar disorder type I, is probably somewhat too restrictive in clinical practice. Due to the clinical heterogeneity of bipolar disorder, the mixed states will define within a dimensional approach, likely in the next DSM- V. As the evolution, the prognosis or the therapeutic strategies differ from what is applied in other thymic episodes, this transition from "mixed state" to manic or depressive episodes "with mixed features" may be relevant in practice.

Add-on memantine to valproate treatment increased HDL-C in bipolar II disorder

Memantine is a noncompetitive NMDA receptor antagonist. As an augmenting agent, it has an antidepressant-like and mood-stabilizing effect. Memantine also reduces binge eating episodes and weight. We investigated whether memantine added on to valproate (VPA) is more effective than VPA alone for treating BP-II depression and improving the patient's metabolic profile. This was a randomized, double-blind, controlled study. BP-II patients undergoing regular VPA treatments were randomly assigned to one of two groups: VPA plus either add-on [1] memantine (5 mg/day) (n = 62) or [2] placebo (n = 73) for 12 weeks. The Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS) were used to evaluate clinical response. Height, weight, fasting serum glucose, fasting total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides were followed regularly. Multiple linear regressions with generalized estimating equation methods were used to analyze the effects of memantine on clinical performance. There were no significant differences in pre- and post-treatment YMRS and HDRS scores between the VPA + memantine and VPA + placebo groups. Although there were no significant differences in the pre- and post-treatment values of most metabolic indices between the two groups, there was a significant increase of HDL-C (p = 0.009) in the VPA + memantine group compared with the VPA + placebo group. This increase remained significant even after controlling for body mass index (BMI) (p = 0.020). We conclude that add-on memantine plus VPA treatment of BP-II depression increases the blood level of HDL-C even in the absence of change in affective symptoms.

TRIAL REGISTRATION

NCT01188148 (https://register.clinicaltrials.gov/), Trial date was from 1st August, 2008 to 31st July, 2012 in National Cheng Kung University and Tri-Service General Hospital.

Bipolar disorder with seasonal pattern: clinical characteristics and gender influences

Bipolar disorder (BD) has a multifactorial etiology with heterogeneous clinical presentations. Around 25% of BD patients may present with a depressive seasonal pattern (SP). However, there are limited scientific data on the prevalence of SP, its clinical manifestations, and any gender influence. Four hundred and fifty-two BD I and II cases (62% female), recruited from three French university-affiliated psychiatric departments, were assessed for SP. Clinical, treatment, and sociodemographic variables were obtained from structured interviews. One hundred and two (23%) cases met DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) criteria for SP, with similar frequency according to gender. Multivariate analysis showed a significant association between SP and BD II (odds ratio [OR] = 1.99, p = 0.01), lifetime history of rapid cycling (OR = 2.05, p = 0.02), eating disorders (OR = 2.94, p = 0.003), and total number of depressive episodes (OR = 1.13, p = 0.002). Seventy-one percent of cases were correctly classified by this analysis. However, when stratifying the analyses by gender, SP was associated with BD II subtype (OR = 2.89, p = 0.017) and total number of depressive episodes (OR = 1.21, p = 0.0018) in males but with rapid cycling (OR = 3.02, p = 0.0027) and eating disorders (OR = 2.60, p = 0.016) in females. This is the first study to identify different associations between SP and clinical characteristics of BD according to gender. The authors suggest that SP represents a potentially important specifier of BD. These findings indicate that seasonality may reflect increased severity or complexity of disorder.

Evidence for seasonal mania: a review

OBJECTIVE

The goal of this article is to summarize the evidence for seasonal mania based on research studies and findings concerning interrelationships among circadian rhythm, manic episodes, and mood stabilizers.

METHODS

The PubMed database was searched using the key word "seasonal mania." This search generated a list of 197 papers published between 1990 and 2011, 29 of which were original research studies on seasonal mania. The findings from these studies were reviewed with regard to their relevance to the mechanisms involved in seasonal mania and strategies for managing mania.

RESULTS

Of the 29 research studies, the majority (n=23) provided evidence for a significant seasonal pattern for mania, while the other 6 studies did not. Most of the studies reported that mania occurred more often during spring and summer and that depression occurred more often during fall and winter. The authors of the studies estimated a prevalence of seasonal mania of 15% among patients with bipolar disorder. It is hypothesized that the underlying mechanism for seasonal mania may be hypersensitivity to bright light that suppresses melatonin production. Both lithium and valproate can counteract the action of bright light in suppressing melatonin and prolong sleep-wake cycles in the circadian rhythms of patients with bipolar disorder. These effects may at least partially explain their efficacy as mood stabilizing agents. No research studies were located that provided information on managing the medication regimen, especially of mood stabilizing medications, based on the seasonal patterns seen in some patients with bipolar disorder in order to reduce the risk of relapse associated with seasonal mania. Positive findings in this area might lead to a new paradigm for the management of patients with bipolar disorder who have seasonal mania.

Further evidence for ClockΔ19 mice as a model for bipolar disorder mania using cross-species tests of exploration and sensorimotor gating

Bipolar disorder (BD) is a pervasive neuropsychiatric disorder characterized by episodes of mania and depression. The switch between mania and depression may reflect seasonal changes and certainly can be affected by alterations in sleep and circadian control. The circadian locomotor output cycles kaput (CLOCK) protein is a key component of the cellular circadian clock. Mutation of the Clock gene encoding this protein in ClockΔ19 mutant mice leads to behavioral abnormalities reminiscent of BD mania. To date, however, these mice have not been assessed in behavioral paradigms that have cross-species translational validity. In the present studies of ClockΔ19 and wildtype (WT) littermate mice, we quantified exploratory behavior and sensorimotor gating, which are abnormal in BD manic patients. We also examined the saccharin preference of these mice and their circadian control in different photoperiods. ClockΔ19 mice exhibited behavioral alterations that are consistent with BD manic patients tested in comparable tasks, including hyperactivity, increased specific exploration, and reduced sensorimotor gating. Moreover, compared to WT mice, ClockΔ19 mice exhibited a greater preference for sweetened solutions and greater sensitivity to altered photoperiod. In contrast with BD manic patients however, ClockΔ19 mice exhibited more circumscribed movements during exploration. Future studies will extend the characterization of these mice in measures with cross-species translational relevance to human testing.

Elevated immune-inflammatory signaling in mood disorders: a new therapeutic target?

Converging translational evidence has implicated elevated immune-inflammatory signaling activity in the pathoetiology of mood disorders, including major depressive disorder and bipolar disorder. This is supported in part by cross-sectional evidence for increased levels of proinflammatory eicosanoids, cytokines and acute-phase proteins during mood episodes, and prospective longitudinal evidence for the emergence of mood symptoms in response to chronic immune-inflammatory activation. In addition, mood-stabilizer and atypical antipsychotic medications downregulate initial components of the immune-inflammatory signaling pathway, and adjunctive treatment with anti-inflammatory agents augment the therapeutic efficacy of antidepressant, mood stabilizer and atypical antipsychotic medications. Potential pathogenic mechanisms linked with elevated immune-inflammatory signaling include perturbations in central serotonin neurotransmission and progressive white matter pathology. Both heritable genetic factors and environmental factors including dietary fatty-acid composition may act in concert to sustain elevated immune-inflammatory signaling. Collectively, these data suggest that elevated immune-inflammatory signaling is a mechanism that is relevant to the pathoetiology of mood disorders, and may therefore represent a new therapeutic target for the development of more effective treatments.

A mutation in CLOCK leads to altered dopamine receptor function

Mice with a mutation in the Clock gene (ClockΔ19) have a number of behavioral phenotypes that suggest alterations in dopaminergic transmission. These include hyperactivity, increased exploratory behavior, and increased reward value for drugs of abuse. However, the complex changes in dopaminergic transmission that underlie the behavioral abnormalities in these mice remain unclear. Here we find that a loss of CLOCK function increases dopamine release and turnover in striatum as indicated by increased levels of metabolites HVA and DOPAC, and enhances sensitivity to dopamine receptor antagonists. Interestingly, this enlarged dopaminergic tone results in downstream changes in dopamine receptor (DR) levels with a surprising augmentation of both D1- and D2-type DR protein, but a significant shift in the ratio of D1 : D2 receptors in favor of D2 receptor signaling. These effects have functional consequences for both behavior and intracellular signaling, with alterations in locomotor responses to both D1-type and D2-type specific agonists and a blunted response to cAMP activation in the ClockΔ19 mutants. Taken together, these studies further elucidate the abnormalities in dopaminergic transmission that underlie mood, activity, and addictive behaviors.

Seasonal influences on admissions for mood disorders and schizophrenia in a teaching psychiatric hospital in Egypt

BACKGROUND

Distinct seasonal variation in hospital admission and various associations with the climatic parameters for mood disorders and schizophrenia have been previously reported in several world regions. There are, however, no North-African studies on this association.

METHODS

The charts of 1987 patients with mood disorders (mania 1181, depression 806) and 1359 patients with schizophrenia admitted from 2003 to 2007 from an university hospital at Mansoura, Egypt, were reviewed. Seasonality was assessed with Cosinor Analysis. Correlations of the rate of admissions for affective disorders and schizophrenia to climatic variables were performed, including lagged and differenced data.

RESULTS

There was a significant seasonal variation in the monthly admission frequencies both for mania (peak in June) and for depression (peak in December) but no significant seasonal variation was found in admissions with diagnosis of schizophrenia. The number of admissions for mania was positively correlated to indicators of temperature and luminosity, but inversely correlated to relative humidity. Quite the opposite, the number of admissions for depression showed a negative correlation to temperature and luminosity, but a positive correlation to relative humidity. 55-57% of the monthly variance of the number of admissions for mood disorders was explained by climatic variables.

CONCLUSIONS

Seasonality of admissions for mood disorders, but not for schizophrenia, has been demonstrated, in an African Mediterranean region with a fairly constant climate. The association between admission rates and climatic variables found in this study could pave the way for further studies aiming at exploration of the biological mechanism of this association as well as tailoring of treatment interventions on mood disorders.

Do symptoms of bipolar disorder exhibit seasonal variation? A multisite prospective investigation

OBJECTIVES

Evidence that symptoms of bipolar disorder (BD) vary seasonally is inconclusive. Here, a multisite prospective investigation of patients with BD was used to test the hypothesis that, on average, depressive symptoms peak in autumn/winter and hypo/manic symptoms peak in spring/summer. Secondary analyses explored gender and diagnosis [bipolar I disorder (BD-I) versus bipolar II disorder (BD-II)] effects on seasonality.

METHODS

A sample of 429 patients with BD (61.6% female; 56.2% BD-I) were recruited from 12 sites across Canada. Clinician-rated measures of manic [Young Mania Rating Scale (YMRS), n = 4,753 total observations] and depression symptoms [Montgomery-Åsberg Depression Rating Scale (MADRS), n = 4,691 observations] were taken at scheduled three-month visits as well as any unscheduled visits. At scheduled visits only, Hamilton Depression Rating Scale (Ham-D) assessments (n = 3,153 observations) were also made. Multi-level modeling (MLM) analyses were conducted separately for the three dependent variables and three definitions of Time: calendar month, nominal season, and harmonic analysis.

RESULTS

Primary analyses of the whole sample found that for manic symptoms (YMRS), neither calendar month nor nominal season were significant, and harmonic analyses found an unpredicted frequency two sinusoid, with peaks at 4th December and 4th June (p < 0.018). Secondary analyses found that this sinusoid approximately fit the YMRS data for females and those diagnosed with BD-II. For depression symptoms measured on the MADRS and Ham-D, no significant seasonal patterns were found in primary analyses of the whole sample. Secondary analyses found a significant increase in MADRS scores in November/December among females, but this pattern was not corroborated in nominal season or harmonic analyses.

CONCLUSIONS

No evidence of systematic seasonal variation in symptoms was found in the sample as a whole. Primary analyses found no evidence that hypo/manic symptoms peaked in the lighter months and depressive symptoms peaked in the darker months. The present findings align with broadly negative conclusions from three earlier prospective investigations, and provide the strongest evidence to date that seasonal changes do not in fact cause coordinated variation in BD symptoms.

Evolutionary origin of bipolar disorder-revised: EOBD-R

The hypothesis of the evolutionary origin of bipolar disorder (EOBD) synthesized ideas about the biological clock and seasonal shifts in mood (Rosenthal, Wehr) with theorizing that bipolar disorder descends from a pyknic (compact, cold-adapted) group (Kretchmer). The hypothesis suggested that bipolar behaviors evolved in the northern temperate zone as highly derived adaptations to the selective pressures of severe climatic conditions during the Pleistocene. Given evidence of Neandertal contributions to the human genome, the hypothesis is extended (EOBD-R) to suggest Neandertal as the ancestral source for bipolar vulnerability genes (susceptibility alleles). The EOBD-R hypothesis explains and integrates existing observations: bipolar disorder has the epidemiology of an adaptation; it is correlated with a cold-adapted build, and its moods vary according to light and season. Since the hypothesis was first published, data consistent with it have continued to appear. Individuals with seasonal affective disorder, which is related to bipolar disorder, have been shown to manifest a biological signal of season change similar to that found in hibernating animals. The involvement of the circadian gene network in the pathophysiology of bipolar disorder has been confirmed. Because selective pressures during the Pleistocene would have been greatest for women of reproductive age, they are expected to manifest winter depression more than males or younger females, which is the case. (This sex difference is also found in hibernating mammals.) Because it is hypothesized that the evolution of bipolar disorder took place in the northern temperate zone during the Pleistocene, it is not expected that individuals of African descent, lacking Neandertal genes, will manifest circular bipolar I disorder, and in fact, the incidence of bipolar disorder among black individuals is less than among whites. A definitive test of the hypothesis is proposed: It is predicted that the bipolar and Neandertal genomes will be more similar than the modern human and Neandertal genomes, and the modern human and San and Yoruba genomes will be more similar than the bipolar and San and Yoruba genomes. Failure to confirm these predictions will falsify the EOBD-R hypothesis. The EOBD-R hypothesis has important implications in the search for bipolar vulnerability genes and our understanding of ourselves and our Neandertal ancestor. At a practical level, confirmation of the EOBD-R hypothesis will boost interest and research in the prevention and management of bipolar symptoms by manipulation of ambient light.

The precipitants of manic/hypomanic episodes in the context of bipolar disorder: a review

BACKGROUND

Mania/hypomania is the hallmark feature of bipolar disorder. This paper aims to review the current evidence in relation to factors hypothesised to precipitate bipolar mania/hypomania, and suggest areas for future research.

METHODS

A selective review of original and review papers was conducted. The electronic databases 'PsycINFO' and 'PubMed' were searched using the following search strings: "bipolar disorder" or "mania" or "hypomania" or "manic-depression" with "triggers" or "precipitants" or "precedents" or "predictors".

RESULTS

There is evidence that goal attainment events, antidepressant medication, disrupted circadian rhythms, spring/summer seasonal conditions, and more tentatively, stressful life events and high emotional expression, may precipitate bipolar mania/hypomania in susceptible individuals. Evidence from case reports and clinical observations are also reported.

DISCUSSION

The pathways to bipolar mania/hypomania may be many and varied, and many of these pathways may be outside the awareness of individuals with bipolar disorder. Greater awareness of the broad number of precipitating factors is needed to inform self-management and psycho-educational programs to build resilience to further episodes. Future research is needed to explore what other factors may precipitate bipolar mania/hypomania, and to determine why some factors may precipitate mania/hypomania in some individuals with bipolar I or II disorder but not in others.

Insight in bipolar disorder: relationship to episode subtypes and symptom dimensions

BACKGROUND

The study of insight in bipolar disorder has received limited attention, despite its potential impact on treatment compliance and prognosis. In the current study we compare insight levels during different phases of bipolar disorder, and consider its relationship to symptoms dimensions and epidemiologic variables.

METHODS

Insight ratings obtained from 156 bipolar subjects in any phase of bipolar disorder were compared. A regression analysis was also conducted to identify symptom dimensions predictive of insight levels.

RESULTS

Greater impairments in insight were observed during pure manic episodes than during mixed or depressed episodes, or during euthymia. Depressive symptoms were associated with better insight. Improvements in insight with treatment were neither complete nor universal. Lack of insight was unrelated to age, years of illness, age of first psychiatric illness, or lifetime number of hospitalizations.

CONCLUSIONS

Although psychosis may be associated with impaired insight, other variables also impact on degree of impaired insight. Specifically, depressed mood appears to be associated with preservation of insight. That relationship may transcend strict syndromal diagnosis.

Further evidence of seasonality of mania in the tropics

BACKGROUND

Findings from various temperate regions have quite consistently shown a spring/summer peak for the occurrence of manic episodes, but inconsistencies can still be found in results from tropical regions. The present study was designed to investigate the seasonal distribution of mania and its correlations to climatic variables, in a large sample of patients visiting the emergency psychiatric room.

METHODS

A hospital registry of 5172 emergency psychiatric visits for mania, 2000-2007, at a public psychiatric hospital at Belo Horizonte, Brazil (latitude 19 degrees 55' S), was analyzed. Seasonality was assessed with Cosinor Analysis. Correlations of the rate of admissions for mania to climatic variables were performed, including lagged and differenced data.

RESULTS

A minor, but significant seasonal pattern was evidenced, with a late winter/spring peak and the nadir in February (late summer). The regression model including secular and seasonal components explained 44.4% of the variance of visits for mania. The rate of emergency visits for mania was negatively correlated to relative humidity and rainfall. Altogether, climatic variables explained 8.1% of the variance in the rate of emergency visits for mania.

LIMITATIONS

Using hospital registry data may have led to misclassification of diagnosis. The ecologic design does not account for seasonal evolution of individual cases.

CONCLUSION

Emergency psychiatric visits for mania were more frequent in late winter/spring, corresponding to the drier seasons of Belo Horizonte. Seasonality of mania in the tropics was corroborated by these results.

Anxiety as a symptom of mixed mania: implications for DSM-5

The recently released preliminary proposal for the DSM-5 diagnostic system includes modification of the mixed mania diagnosis symptom set. That definition includes the long-overdue exclusion of nonspecific signs and symptoms, as well as the inclusion of psychomotor retardation. Anxiety is specifically excluded from the definition. The current report reviews studies to establish that psychomotor retardation would have limited utility in the definition, in contrast to anxiety, which is a core symptom of the mixed manic subtype.

Relationship among latitude, climate, season and self-reported mood in bipolar disorder

OBJECTIVE

Many researchers have analyzed seasonal variation in hospital admissions for bipolar disorder with inconsistent results. We investigated if a seasonal pattern was present in daily self-reported daily mood ratings from patients living in five climate zones in the northern and southern hemispheres. We also investigated the influence of latitude and seasonal climate variables on mood.

METHOD

360 patients who were receiving treatment as usual recorded mood daily (59,422 total days of data). Both the percentage of days depressed and hypomanic/manic, and the episodes of depression and mania were determined. The observations were provided by patients from different geographic locations in North and South America, Europe and Australia. These data were analyzed for seasonality by climate zone using both a sinusoidal regression and the Gini index. Additionally, the influence of latitude and climate variables on mood was estimated using generalized linear models for each season and month.

RESULTS

No seasonality was found in any climate zone by either method. In spite of vastly different weather, neither latitude nor climate variables were associated with mood by season or month.

CONCLUSION

Daily self-reported mood ratings of most patients with bipolar disorder did not show a seasonal pattern. Neither climate nor latitude has a primary influence on the daily mood changes of most patients receiving medication for bipolar disorder.

Concordance of self-rated and observer-rated dysphoric symptoms in mania

OBJECTIVES

High rates of some depressive symptoms occur in both mixed and pure manic episodes. This study examined whether manic subjects identify these depressive symptoms by self-report consistently with observer ratings, whether dysphoric symptoms are self-rated differently in mixed compared to pure manic episodes, and whether discriminative self-rated dysphoric symptom sets agree with those established by observer ratings.

METHODS

Ninety-four inpatients meeting DSM-IV criteria for mania were classified as in pure or mixed episodes. Dysphoric symptoms were evaluated with the Hamilton Depression Rating Scale (HDRS) and the self-rated Carroll Depression Scale (CDS). Total scores and individual symptom scores on the two scales were compared, as were differences between the manic and mixed subtypes. Positive predictive values (PPV) of individual CDS statements for a diagnosis of a mixed bipolar episode were calculated. Those with a PPV of 0.5 or greater were summed across all subjects and the distributions within the bipolar manic and mixed groups inspected.

RESULTS

Self-rated depressive symptoms were highly concordant with observer-rated depressive symptoms in mania. Differences were demonstrated between mixed and pure manic subjects based on self-report, and these differences were similar to those observed with HDRS evaluations. A group of 8 dysphoric symptoms discriminated mixed from pure manic episodes on both scales. These symptoms were depressed mood, pathological guilt, suicidal tendency, anhedonia, psychomotor agitation, psychic and somatic anxiety, and general somatic symptoms (fatigue).

CONCLUSIONS

Manic patients report depressive symptoms consistently with observer ratings. Self-rated dysphoric symptoms differ significantly between mixed and pure manic episodes. Patient self-rating is another tool which may help in the diagnosis of mixed mania and the recognition of depressive symptoms during manic episodes.

LIMITATIONS

The current study included patients who were evaluated during inpatient hospitalization only. The study included only subjects capable and willing to give written informed consent. Generalizability to other bipolar patients is not established.

Early intervention in bipolar disorders: clinical, biochemical and neuroimaging imperatives

In the absence of clear targets for primary prevention of many psychiatric illnesses, secondary prevention becomes the most feasible therapeutic target, and is best encompassed by the concept of early intervention. This construct encompasses the goals of minimising diagnostic delay and the prompt initiation of clinically appropriate therapy. This paper develops the rationale for early intervention in bipolar disorder. Three interrelated themes are discussed; the clinical data supporting the value of prompt diagnosis and treatment in bipolar disorder, the putative biochemical mechanisms underlying the pathophysiological processes, and the parallel concept of neuroprotection, and the developing neuroimaging data that supports early intervention. Early initiation of appropriate therapy may potentially facilitate improved clinical outcomes, and further might allow the secondary prevention of the sequelae of untreated illness, which include the deleterious impact on family relationships, psychosexual and vocational development, identity and self-concept and self-stigma.

Pure and mixed manic subtypes: a review of diagnostic classification and validation

OBJECTIVE

To review issues surrounding the diagnosis and validity of bipolar manic states.

METHODS

Studies of the manic syndrome and its diagnostic subtypes were reviewed emphasizing historical development, conceptualizations, formal diagnostic proposals, and validation.

RESULTS

Definitions delineating mixed and pure manic states derive some validity from external measures. DSM-IV and ICD-10 diagnosis of bipolar mixed states are too rigid and less restrictive definitions can be validated. Anxiety is a symptom often overlooked in diagnosis of manic subtypes and may be relevant to the mixed manic state. The boundary for separation of mixed mania and depression remains unclear. A 'pure' non-psychotic manic state similar to Kraepelin's 'hypomania' has been observed in several independent studies.

CONCLUSIONS

Issues surrounding diagnostic subtyping of manic states remain complex and the debates surrounding categorical versus dimensional approaches continue. To the extent that categorical approaches for mixed mania diagnosis are adopted, both DSM-IV and ICD-10 are too rigid. Inclusion of non-specific symptoms in definitions of mixed mania, such as psychomotor agitation, does not facilitate and may hinder the diagnostic separation of pure and mixed mania. The inclusion of a diagnostic seasonal specifier for DSM-IV, which is currently based on seasonal patterns for depression might be expanded to include seasonal patterns for mania. Boundaries between subtypes may be 'fuzzy' rather than crisp, and graded approaches could be considered. With the continued development of new tools, such as imaging and genetics, alternative approaches to diagnosis other than the purely symptom-centric paradigms might be considered.

Clinical and prognostic implications of seasonal pattern in bipolar disorder: a 10-year follow-up of 302 patients

BACKGROUND

More than 20% of bipolar patients may present with seasonal pattern (SP). Seasonality can alter the course of bipolar disorder. However, to date, long-term follow-up studies of bipolar patients presenting with SP are scarce. We present a 10-year follow-up study comparing clinical and demographic features of bipolar patients with and without SP.

METHOD

Three hundred and twenty-five bipolar I and II patients were followed up for at least 10 years. SP was defined according to DSM-IV criteria. Clinical variables were obtained from structured interviews with the patients and their relatives. Patients with and without SP were compared regarding clinical and sociodemographic variables and a stepwise logistic regression was performed.

RESULTS

Seventy-seven patients (25.5%) were classified as presenting with SP, while 225 (74.5%) were considered as presenting with no significant seasonal variation. Twenty-three patients (7%) were excluded from the study because it was unclear whether they had seasonality or not. There were no differences between groups regarding demographic variables. Patients with SP predominantly presented with bipolar II disorder, depressive onset, and depressive predominant polarity. The greater burden of depression did not correlate with indirect indicators of severity, such as suicidality, hospitalizations or psychotic symptoms.

CONCLUSIONS

Our study links the presence of SP with both bipolar II disorder and predominant depressive component. However, we could not find any difference regarding functionality or hospitalization rates. Modifications in the criteria to define SP are suggested for a better understanding of bipolar disorder.

The impact of environmental temperature on lithium serum levels

OBJECTIVES

Three studies have reported a seasonal variation in lithium serum levels, with higher levels during summer. Our objective was to investigate the impact of actual environmental temperature on lithium serum levels.

METHODS

A retrospective study was conducted using available records of lithium serum levels for the period between January 1995 and July 2004, obtained from three large teaching hospitals in The Netherlands. Lithium serum levels were linked to season and average daily temperature data obtained from the Royal Netherlands Meteorological Institute. An analysis was performed on all lithium serum levels not accounting for the intra-individual dependency of lithium serum levels. The association between season, temperature and both absolute lithium serum level and the frequency of potentially toxic serum levels was investigated. A mixed model analysis, accounting for intra-individual dependency of lithium serum levels, was performed.

RESULTS

A total of 41,102 lithium serum levels (3,054 patients) were included. A significant difference in mean lithium serum levels across seasons (p < 0.001) and temperature categories (p = 0.001) was found, peaking in summer [0.761 mmol/L, +/- standard error of the mean (SEM) 0.002] and at temperatures of 15-20 degrees C [0.762 mmol/L (+/- SEM 0.005)], and at a minimum in winter [0.748 mmol/L (+/- SEM 0.002)] and at <0 degrees C [0.741 mmol/L (+/- SEM 0.005)]. The relative frequency of potentially toxic serum levels significantly differed between seasons (p = 0.023, highest in winter), but not between temperature categories (p = 0.481). A significant positive association for intra-individual lithium serum level and season (p < 0.001) and temperature (p < 0.001) was established.

CONCLUSIONS

Season and environmental temperature have a statistically significant but therapeutically irrelevant effect on lithium serum levels.

Seasonal variations in bipolar disorder admissions and the association with climate: a population-based study

OBJECTIVE

Although seasonal influences on bipolar disorder admissions have long been observed, the issues of seasonality on different subtypes of mood episodes and the effects of associated climatic parameters remain controversial. This study sets out to examine seasonal variations in bipolar disorder admissions and the association with climate in Taiwan, a subtropical area with fairly constant weather conditions.

METHODS

This retrospective population-based study uses the Taiwan National Health Insurance Research Database for 1999-2003, identifying 15,060 admissions for bipolar disorder, comprising of 8631 manic, 2078 depressive and 4351 mixed/unspecified episodes. The auto-regressive integrated moving average model was applied to examine the presence of seasonality and the association with climate in each subtype of mood episodes.

RESULTS

Admission peaks were noted during spring/summer, early winter and early spring, for manic, depressive and mixed/unspecified episodes, respectively, while the associations with climatic parameters varied between the subtypes of mood episodes.

CONCLUSIONS

Seasonality in bipolar disorder does exist for all subtypes of mood episodes. The distinct seasonal patterns and various associations with the climatic parameters imply different underlying mechanisms for the onset of each subtype of mood episodes. The association between admission rates and certain climatic variables found in this study is informative and could pave the way for future studies aimed at exploring the influence of climate on the psychopathology of bipolar patients as well as the underlying mechanisms.

Seasonal influences on first-episode admission in affective and non-affective psychosis

BACKGROUND

Since bipolar affective disorder has been recorded, clinicians treating patients with this disorder have noted the cyclic nature of episodes, particularly an increase in mania in the spring and summer months and depression during winter.

OBJECTIVE

The aim of this study was to investigate seasonality in symptom onset and service admissions over a period of 10 years in a group of patients (n= 359) with first-episode (FE) mania (n= 133), FE schizoaffective disorder (n= 49) and FE schizophrenia (n= 177).

METHOD

Patients were recruited if they were between 15 and 28 years of age and if they resided in the geographical mental health service catchment area. The number of patients experiencing symptom onset and service admission over each month and season was recorded.

RESULTS

In terms of seasonality of time of service admission, the results indicate a high overall seasonality (particularly in men), which was observed in both the schizoaffective and the bipolar groups. In terms of seasonality of symptom onset, the results indicate that seasonality remains in the male bipolar group, but other groups have no seasonal trend.

CONCLUSIONS

This provides further evidence that systems mediating the entrainment of biological rhythms to the environment may be more pronounced in BPAD than in schizoaffective disorder and schizophrenia. These results may help facilitate the preparedness of mental heath services for patients at different times of the year.

Seasonal variation of sexual abuse in Santiago de Chile

BACKGROUND

Seasonal variations of sexual crime have been seldom studied in the world. Santiago, a city situated at 33 degrees south latitude with a well defined four season climate, has a reliable forensic registry, providing a good opportunity for the assessment of seasonality in this type of crime.

MATERIALS AND METHODS

After studying monthly records of sexual abuse from the registry of the Servicio Médico Legal of Santiago between 1990 and 2001, a ratio of observed to expected monthly frequency was obtained, allowing the assessment of the seasonal character of the phenomenon.

RESULTS

A total number of 11,844 cases of sexual abuse were recorded during 12 years of the study. Statistically significant differences could be demonstrated between spring and autumn, with a peak in November and a nadir in June.

CONCLUSIONS

A distinct seasonal pattern can be set forth for sexual abuse in Santiago, Chile.

Distinct seasonality of depressive episodes differentiates unipolar depressive patients with and without depressive mixed states

BACKGROUND

The bipolar nature of unipolar depression with depressive mixed states (DMX) needs further validation studies. The seasonality of depressive episodes is indicated to be different between unipolar and bipolar depressions. We therefore explored the seasonal pattern of depressive episodes in unipolar depressive patients with DMX.

METHODS

The subjects were 958 consecutive depressive inpatients for a 6-year period. For defining DMX, previously validated operational criteria were used (2 or more of 8 manic or mania-related symptoms: flight of idea, logorrhea, aggression, excessive social contact, increased drive, irritability, racing thoughts, and distractibility). Onsets of the index depressive episodes during each of the 12 calendar months were summed up over the 6-year for bipolar depressive patients (N = 95), and unipolar depressive patients with (N = 77) and without DMX (N = 786) separately. An appropriate statistic was used for testing seasonality.

RESULTS

A significant seasonal variation with a large peak in spring was recognized in unipolar depression without DMX, while both bipolar depression and unipolar depression with DMX had a significant fall peak. The monthly distribution of depressive episodes was significantly different between unipolar depression without DMX and other 2 diagnostic categories. Similar results were obtained in separate analyses for each gender.

LIMITATIONS

Further replication study using an epidemiological or outpatient sample is needed. Bipolar I and II patients were combined due to a small number of bipolar II patients in this sample.

CONCLUSION

Unipolar depression with DMX has a seasonal pattern similar to bipolar depression. The finding provides further evidence of the bipolar nature of unipolar depression with DMX.

Effect of sodium valproate on nocturnal melatonin sensitivity to light in healthy volunteers

Sensitivity of the pineal hormone melatonin to bright light at night has been proposed as a putative marker of bipolar affective disorder. Patients with bipolar disorder have a super-sensitive melatonin response to light. No studies have investigated whether super-sensitivity is due to agents used to treat the illness or is associated with the disorder per se. We investigated the effect of valproate on this phenomenon. Melatonin sensitivity to light was determined on two nights in 12 healthy volunteers (5M, 7F). Between testing nights participants received 200 mg of valproate b.d. for 5 days. Valproate significantly decreased the sensitivity of melatonin to light. On the other hand, valproate had no effect on overall melatonin secretion or dim light melatonin onset. The ability of valproate to decrease the sensitivity of melatonin to light may relate to its therapeutic effect in bipolar disorder--an ability to lengthen circadian period similar to that of lithium.

Seasonality in a community sample of bipolar, unipolar and control subjects

BACKGROUND

This study examined seasonality in a community sample of five diagnostic groups: normal subjects, those with non-seasonal depression (NSD), seasonal depression (SD), non-seasonal bipolar disorder (NSBD) and seasonal bipolar disorder (SBD).

METHODS

Telephone interviews were conducted across the Province of Ontario. Seasonal changes in mood and behaviour were determined using the Seasonal Pattern Assessment Questionnaire (SPAQ). Five additional seasonality items consisting of depressive symptoms were included in the interview. The mean global severity of seasonality (GSS) scores were obtained and the entire inventory of 11 seasonality items were compared across the identified groups.

RESULTS

The mean GSS score for the controls was 5.2 (S.D. = 4.0), 8.0 (S.D. = 4.9) for NSD, 10.5 (S.D. = 3.9) for SD, 10.5 (S.D. = 5.4) for NSBD and 13.4 (S.D. = 5.4) for SBD. These scores differed significantly (F = 61.68, df = 4, p < 0.001). For the majority of the individual items, the SBD group rated the highest degree of seasonal fluctuation, while the NSBD and SD groups had nearly identical item scores.

LIMITATIONS

Limitations in this study include the relatively small number of subjects in the NSBD and SBD groups, and the inherent limitations in a telephone interview.

CONCLUSIONS

Individuals with bipolar disorder experience greater seasonality than those with depression or healthy controls. Even the non-seasonal bipolar group had as much seasonal fluctuation as the seasonal depression group, which has important implications for the management of bipolar illness.

[Diagnosis and treatment of mixed states]

Mixed States are described in the literature using based on different definitions resulting in different descriptions of the clinical and demographic characteristics, of these episodes, but although they are always asdeemed a severe form of Bipolar disorder with worse prognosis and more prevalent than previously described. The aim of this article is to present a review of these different definitions and their impact on the study of mixed states. Pharmacological treatment is also discussed.

High prevalence of mental disorders in primary care

OBJECTIVE

To determine the prevalence of common mental disorders in an adult primary care population.

DESIGN

Cross-sectional survey in randomly selected subjects, using the PRIME-MD questionnaire.

SETTING

Eighty-six general practices in Belgium.

SUBJECTS

A total of 2316 randomly selected patients, aged 18 years or older and consulting their general practitioner for other than administrative reasons alone, with slightly more women (58.1%) than men (41.3%). MAIN OUTCOME RESULT: Prevalence rates of mental disorders most commonly seen in primary care practice (mood, anxiety, somatoform, eating and alcohol disorders).

METHODS

To facilitate data collection and processing, the entire PRIME-MD questionnaire was programmed on a handheld computer. Patient answers and physician assessments were immediately electronically recorded during the interview. All investigators were trained on the use of the PRIME-MD. The recruitment period lasted 6 weeks: from 15 February to 25 March 1999, and patients were randomly selected for the interview based on a computerized procedure.

RESULTS

Although only 5.4% of all patients consulted for a psychiatric reason, a threshold/subthreshold psychiatric disorder was detected in 42.5% of all patients. Most commonly detected disorders were mood disorders in 31.0% (major depressive disorder, 13.9% and dysthymia, 12.6%), anxiety disorders in 19.0% (generalized anxiety disorder, 10.3%), somatoform disorders in 18.0% and probable alcohol abuse/dependence in 10.1%. The results also showed the important rate of comorbidity between these disorders.

CONCLUSION

The present study confirms the high prevalence of mental disorders in a general practice setting, and their frequent association. Prevalence rates of our study are even higher than those obtained in previously conducted trials. Our study also demonstrates the utility of the PRIME-MD as a screening tool for mental disorders in primary care. In addition the use of the handheld computer software version of the PRIME-MD allowed us to screen for mental disorders in patients who are unable to attend the GP office and are seen during 'home' visits.

Thyroid function in mixed and pure manic episodes

OBJECTIVES

Associations of both overt thyroid disease as well as subclinical thyroid abnormalities with affective disorders have been well established. Similar associations have been reported with mixed mania and rapid cycling bipolar disorder. We tested for differences in overt and subclinical thyroid disease and subclinical differences in a large series of bipolar patients examined during mixed or pure manic episodes.

METHODS

Rates of previously diagnosed thyroid disease were compared by sex, race and manic subtype (mixed versus pure) in 443 patients. Serum thyroid stimulating hormone (TSH) and free thyroxine (FT4) concentrations obtained from patients with no clinical thyroid disease collected during manic and mixed bipolar episodes were compared using ANOVA statistics. Race was also included in the model and age was covaried.

RESULTS

Rates of thyroid disease, in particular hypothyroidism, were higher in females and white people, and increased with advancing age. No differences were noted between subjects sampled during mixed or pure manic episodes. In patients with no history of thyroid disease, serum TSH and FT4 concentrations did not differ between manic subtypes or between sexes. TSH levels however, were significantly lower in African Americans.

CONCLUSIONS

We did not confirm past reports of associations of overt or subclinical thyroid disease with mixed manic episodes. African Americans had significantly lower serum TSH concentrations than white people, while FT4 levels did not differ.

A prospective study of inter-episode consistency of manic and mixed subtypes of bipolar disorder

BACKGROUND

Few studies have compared symptom presentations across manic or mixed episodes in manic-depressive patients.

METHODS

In the current study we report on symptom presentations of 68 prospectively-evaluated subjects diagnosed with Bipolar Disorder during two discrete manic or mixed episodes. Each episode was categorized using DSM-IIIR criteria for Bipolar Disorder, manic or mixed, as well as a less restrictive definition for manic and mixed states derived from receiver operating characteristic (ROC) analysis of symptoms.

RESULTS

The occurrence of mixed bipolar episodes was not random using either the DSM-IIIR or ROC-derived definitions of mixed episodes.

LIMITATIONS

Subjects were not all fully medication-free at the time of evaluation which may have altered symptom presentation. The total duration of the study was limited, with the longest inter-episode interval under 6 years.

CONCLUSIONS

Although there was variability in mixed symptomatology between episodes, the occurrence of mixed episodes was not random. Manic and mixed episodes tend to recur true to type.