Seasonality of mania in New Zealand

Converging evidence that short-active photoperiod increases acetylcholine signaling in the hippocampus

Seasonal variations in environmental light influence switches between moods in seasonal affective disorder (SAD) and bipolar disorder (BD), with depression arising during short active (SA) winter periods. Light-induced changes in behavior are also seen in healthy animals and are intensified in mice with reduced dopamine transporter expression. Specifically, decreasing the nocturnal active period (SA) of mice increases punishment perseveration and forced swim test (FST) immobility. Elevating acetylcholine with the acetylcholinesterase inhibitor physostigmine induces depression symptoms in people and increases FST immobility in mice. We used SA photoperiods and physostigmine to elevate acetylcholine prior to testing in a probabilistic learning task and the FST, including reversing subsequent deficits with nicotinic and scopolamine antagonists and targeted hippocampal adeno-associated viral administration. We confirmed that physostigmine also increases punishment sensitivity in a probabilistic learning paradigm. In addition, muscarinic and nicotinic receptor blockade attenuated both physostigmine-induced and SA-induced phenotypes. Finally, viral-mediated hippocampal expression of human AChE used to lower ACh levels blocked SA-induced elevation of FST immobility. These results indicate that increased hippocampal acetylcholine neurotransmission is necessary for the expression of SA exposure-induced behaviors. Furthermore, these studies support the potential for cholinergic treatments in depression. Taken together, these results provide evidence for hippocampal cholinergic mechanisms in contributing to seasonally depressed affective states induced by short day lengths.

Seasonal and temperature effect on serum lithium concentrations

BACKGROUND

Lithium remains the gold standard treatment for bipolar disorder. However, it has a very narrow therapeutic index (0.6-0.8 mmol/L). It has been suggested that high environmental temperature can lead to dehydration, elevated plasma lithium concentration and then lithium toxicity.

OBJECTIVES

We aimed to investigate the effect of seasonal and short-term changes in temperature on serum lithium concentrations in Sydney, Australia.

METHODS

We retrospectively analysed data from all patients who had serum lithium concentrations taken from the Prince of Wales and Sutherland Hospitals between 2008 and 2018. Temperature data came from the Bureau of Meteorology. We examined correlations between lithium concentrations and the preceding 5 days maximum temperatures, month and season. We also performed a longitudinal analysis of the effect of temperature and seasons within selected patients who had repeated levels.

RESULTS

A total of 11,912 serum lithium concentrations from 2493 patients were analysed. There was no significant association between higher lithium concentration and preceding higher temperatures (r = -0.008, p = 0.399). There was also no important seasonal or monthly variation, across all patients or in the smaller cohort with longitudinal data (n = 123, r = 0.008, 95% confidence interval: [-0.04, 0.06]).

CONCLUSION

There were no clinically important differences in serum lithium concentration related to seasons, months or temperatures, which suggests that patients on lithium are able to adequately maintain hydration during hot weather in Sydney.

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.

Mice with reduced DAT levels recreate seasonal-induced switching between states in bipolar disorder

Developing novel therapeutics for bipolar disorder (BD) has been hampered by limited mechanistic knowledge how sufferers switch between mania and depression-how the same brain can switch between extreme states-described as the "holy grail" of BD research. Strong evidence implicates seasonally-induced switching between states, with mania associated with summer-onset, depression with winter-onset. Determining mechanisms of and sensitivity to such switching is required. C57BL/6J and dopamine transporter hypomorphic (DAT-HY 50% expression) mice performed a battery of psychiatry-relevant behavioral tasks following 2-week housing in chambers under seasonally relevant photoperiod extremes. Summer-like and winter-like photoperiod exposure induced mania-relevant and depression-relevant behaviors respectively in mice. This behavioral switch paralleled neurotransmitter switching from dopamine to somatostatin in hypothalamic neurons (receiving direct input from the photoperiod-processing center, the suprachiasmatic nucleus). Mice with reduced DAT expression exhibited hypersensitivity to these summer-like and winter-like photoperiods, including more extreme mania-relevant (including reward sensitivity during reinforcement learning), and depression-relevant (including punishment-sensitivity and loss-sensitivity during reinforcement learning) behaviors. DAT mRNA levels switched in wildtype littermate mice across photoperiods, an effect not replicated in DAT hypomorphic mice. This inability to adjust DAT levels to match photoperiod-induced neurotransmitter switching as a homeostatic control likely contributes to the susceptibility of DAT hypormophic mice to these switching photoperiods. These data reveal the potential contribution of photoperiod-induced neuroplasticity within an identified circuit of the hypothalamus, linked with reduced DAT function, underlying switching between states in BD. Further investigations of the circuit will likely identify novel therapeutic targets to block switching between states.

The International College of Neuropsychopharmacology (CINP) Treatment Guidelines for Bipolar Disorder in Adults (CINP-BD-2017), Part 1: Background and Methods of the Development of Guidelines

BACKGROUND

This paper includes a short description of the important clinical aspects of Bipolar Disorder with emphasis on issues that are important for the therapeutic considerations, including mixed and psychotic features, predominant polarity, and rapid cycling as well as comorbidity.

METHODS

The workgroup performed a review and critical analysis of the literature concerning grading methods and methods for the development of guidelines.

RESULTS

The workgroup arrived at a consensus to base the development of the guideline on randomized controlled trials and related meta-analyses alone in order to follow a strict evidence-based approach. A critical analysis of the existing methods for the grading of treatment options was followed by the development of a new grading method to arrive at efficacy and recommendation levels after the analysis of 32 distinct scenarios of available data for a given treatment option.

CONCLUSION

The current paper reports details on the design, method, and process for the development of CINP guidelines for the treatment of Bipolar Disorder. The rationale and the method with which all data and opinions are combined in order to produce an evidence-based operationalized but also user-friendly guideline and a specific algorithm are described in detail in this paper.

Examining for any impact of climate change on the association between seasonality and hospitalization for mania

BACKGROUND

Studies have established higher rates of hospitalization for mania in spring and summer and posit various explanatory climatic variables. As the earth's climate is changing, we pursue whether this is reflected in the yearly seasonal variation in hospitalizations for mania. This would be indicated by the presence of secular changes in both the hospitalization seasonal pattern and climatic variables, and associations between both variable sets.

METHODS

Data were obtained for 21,882 individuals hospitalized to psychiatric hospitals in the Australian state of New South Wales (NSW) over a 14-year period (2000-2014) with ICD-diagnosed mania - and with NSW population figures and salient climatic variables collected for the same period. Regression analyses were conducted to examine the predictive value of climate variables on hospital admissions.

RESULTS

Data quantified a peak for manic admissions in spring of the southern hemisphere, in the months of October and November. There was a significant linear increase in manic admissions (0.5%/year) over the 14-year time period, with significant variation across years. In terms of climatic variables, there was a significant linear trend over the interval for solar radiation, although the trend indicated a decrease rather than an increase. Seasonal variation in admissions was most closely associated with two climate variables - evaporation in the current month and temperature in the previous month.

LIMITATIONS

Hospitalization rates do not necessarily provide an accurate estimate of the onset of manic episodes and findings may be limited to the southern hemisphere, or New South Wales.

CONCLUSIONS

While overall findings do not support the hypothesis that climate change is leading to a higher seasonal impact for manic hospital admissions in the southern hemisphere, analyses identified two climate/weather variables - evaporation and temperature - that may account for the yearly spring excess.

Seasonality of hospital admissions for mental disorders in Hanoi, Vietnam

BACKGROUND

Some studies have shown a relationship between seasonality in weather patterns and depressive and behavioural disorders, especially in temperate climate regions. However, there is a lack of studies describing the seasonal patterns of hospital admissions for a variety of mental disorders in tropical and subtropical nations. The aim of this study has been to examine the relationship between seasons and daily hospital admissions for mental disorders in Hanoi, Vietnam.

DESIGNS

A 5-year database (2008-2012) compiled by Hanoi Mental Hospital covering mental disorder admissions diagnosed by the International Classification of Diseases 10 was analysed. A negative binominal regression model was applied to estimate the associations between seasonality and daily hospital admissions for mental disorders, for all causes and for specific diagnoses.

RESULTS

The summer season indicated the highest relative risk (RR=1.24, confidence interval (CI)=1.1-1.39) of hospital admission for mental disorders, with a peak in these cases in June (RR=1.46, CI=1.19-1.7). Compared to other demographic groups, males and the elderly (aged over 60 years) were more sensitive to seasonal risk changes. In the summer season, the RR of hospital visits among men increased by 26% (RR=1.26, CI=1.12-1.41) and among the elderly by 23% (RR=1.23, CI=1.03-1.48). Furthermore, when temperatures including minimum, mean, and maximum increased 1°C, the number of cases for mental disorders increased by 1.7%, 2%, and 2.1%, respectively.

CONCLUSION

The study results showed a correlation between hospital admission for mental disorders and season.

Seasonal variations in rates of hospitalisation for mania and hypomania in psychiatric hospitals in NSW

BACKGROUND

A number of studies have established that manic patients have higher rates of hospitalization in spring. There appears to be no data evaluating whether there is any seasonal variation in hospitalization for those with hypomania.

METHODS

Data were obtained for 27,255 individuals hospitalized in NSW psychiatric hospitals over a 14-year period (2000-2014) for ICD-10 diagnosed mania or hypomania. Graphical analyzes examined rates of hospitalisation for hypomania and mania separately, using monthly and seasonal averages.

RESULTS

Admission rates were higher for mania compared to hypomania and there was a similar pattern across seasons - with admissions being at their lowest in autumn, increasing in winter, and at their highest for spring. Monthly percentage scores were similar for mania and hypomania and indicated lower admission rates in the first six months of the year (January-June), with a sudden increase in July, and followed by a more gradual increase until December.

LIMITATIONS

Hospitalization rates do not necessarily provide an accurate estimate of the onset of hypo/manic episodes, while the validity of those assigned a diagnosis of hypomania could not be established, allowing the possibility that many may have had manic episodes.

CONCLUSIONS

Findings indicate that hypomania shows a similar seasonal pattern to mania.

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.

Comparison of precipitating factors for mania and partial seizures: Indicative of shared pathophysiology?

OBJECTIVES

Mania in bipolar disorder (BD) and partial (focal) seizures (PS) arising from the temporal lobes, have a number of similarities. Typically, a chronic course of the disorders is punctuated by acute illness episodes. Common features of episodes may include sensory, perceptual, cognitive and affective changes. Both respond to anticonvulsant treatment. Common mechanisms imputed include neurotransmitters and kindling processes. Further investigation may improve understanding of the occurrence of both mania and PS, casting light on the relevance of temporal lobe mediated processes and pathology. One avenue of investigation is to compare aetiological factors and determine the extent of overlap which may indicate shared brain localization or pathophysiology. Aetiology includes predisposing, precipitating or perpetuating factors. This paper examines the literature on precipitating factors of mania, first or subsequent episode, and of PS in diagnosed epilepsy, which is the second or subsequent seizure, to identify the extent and nature of their overlap.

METHOD

Narrative review based on a literature search of PubMed and Google Scholar.

RESULTS

Precipitating factors for both mania and PS were stress, sleep deprivation, antidepressant medication and, tentatively, emotion. For mania alone, goal-attainment events, spring and summer season, postpartum, and drugs include steroids and stimulants. For PS alone, winter season, menstruation and specific triggers in complex reflex epilepsies. Those not substantiated include lunar phase and menopause. A wide range of chemicals may provoke isolated seizures but by definition epilepsy requires at least two seizures.

CONCLUSIONS

The overlap of precipitating factors in mania and PS imply that common brain processes may contribute to both, consistent with findings from neuroscience research.

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.

Investigating the mechanism(s) underlying switching between states in bipolar disorder

Bipolar disorder (BD) is a unique disorder that transcends domains of function since the same patient can exhibit depression or mania, states with polar opposite mood symptoms. During depression, people feel helplessness, reduced energy, and risk aversion, while with mania behaviors include grandiosity, increased energy, less sleep, and risk preference. The neural mechanism(s) underlying each state are gaining clarity, with catecholaminergic disruption seen during mania, and cholinergic dysfunction during depression. The fact that the same patient cycles/switches between these states is the defining characteristic of BD however. Of greater importance therefore, is the mechanism(s) underlying cycling from one state - and its associated neural changes - to another, considered the 'holy grail' of BD research. Herein, we review studies investigating triggers that induce switching to these states. By identifying such triggers, researchers can study neural mechanisms underlying each state and importantly how such mechanistic changes can occur in the same subject. Current animal models of this switch are also discussed, from submissive- and dominant-behaviors to kindling effects. Focus however, is placed on how seasonal changes can induce manic and depressive states in BD sufferers. Importantly, changing photoperiod lengths can induce local switches in neurotransmitter expression in normal animals, from increased catecholaminergic expression during periods of high activity, to increased somatostatin and corticotrophin releasing factor during periods of low activity. Identifying susceptibilities to this switch would enable the development of targeted animal models. From animal models, targeted treatments could be developed and tested that would minimize the likelihood of switching.

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.

A genome-wide association study of seasonal pattern mania identifies NF1A as a possible susceptibility gene for bipolar disorder

OBJECTIVE

The use of subphenotypes may be an effective approach for genetic studies of complex diseases. Manic episodes with a seasonal pattern may distinguish phenotypic subgroups of bipolar subjects that may also differ genetically.

METHOD

We have performed a genome-wide association study using GAIN genotype data from the Bipolar Genome Study (BiGS) and bipolar subjects that were categorized as having either seasonal or non-seasonal patterned manic episodes.

RESULTS

A bipolar case-only analysis identified three genomic regions that differed between seasonal and non-seasonal patterned manic episodes of bipolar subjects. The most significant association was for rs41350144, which lies within an intron of NF1A gene on 1p31 (P=3.08×10(-7), OR=2.27). Haplotype construction using flanking three SNPs (rs41453448, rs1125777, and rs12568010) spanning 7549bp showed a more significant association (P=2.12×10(-7), OR=0.4).

CONCLUSIONS

These data suggest that genetic variants in the NF1A gene region may predispose to seasonal patterned of mania in bipolar disorder.

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.

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.

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.

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.

A significant correlation between ward temperature and the severity of symptoms in schizophrenia inpatients--a longitudinal study

BACKGROUND

Preliminary data suggest that schizophrenia outpatients' mental status might be affected, at least to some extent, by environmental temperature. To further substantiate the potential role of environmental temperature and schizophrenic symptoms we examined, in a naturalistic design, the relationship between environmental temperature of schizophrenia inpatients (i.e., ward temperature) and their mental status.

METHODS

Mean daily temperature of a closed psychiatric ward was monitored for 32 consecutive weeks. Temperature assessments were performed at 3 different locations within the ward at the same hour daily. Mean daily temperature was defined as the average of the 3 values. During each of the 32 weeks of the study, the inpatients were divided into two sub-groups: schizophrenia patients (n=22-34 patients/week) and non-schizophrenia psychotic patients (n=5-12 patients/week). The mental status of all participants was evaluated weekly using the positive and negative syndrome scale (PANSS). All participants were treated with antipsychotics during the entire study period.

RESULTS

Schizophrenia patients' total PANSS score, as well as each of the PANSS' subscales (positive, negative, general psychopathology, depression) were positively and significantly correlated with ward temperature (r=0.52-0.64; p=0.002-0.0001). No correlation was found between ward temperature and any of the PANSS' subscales in the non-schizophrenia psychotic subjects.

CONCLUSION

Our results suggest that schizophrenia inpatients' mental status might be modulated, at least to some extent, by environmental (i.e., ward) temperature and that this phenomenon is specific to schizophrenia patients. Our findings imply the need for optimally adjusting ward temperature (e.g., about 19 degrees C in this study) for the management of patients with acute psychotic exacerbation of schizophrenia.

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.

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.

Treatment of seasonal affective disorder: unipolar versus bipolar differences

Evidence-based treatments for seasonal affective disorder (SAD) include light therapy and pharmacotherapy. We briefly review the diagnosis and treatment of SAD, focusing on clinical and treatment differences between patients with unipolar and bipolar illness. Special considerations for the management of SAD in patients with bipolar disorder are discussed, including the need to monitor for emergence of manic and hypomanic mood switches, to use mood stabilizers in patients with bipolar I disorder, and to be aware of potential interactions between bright light and medications used in treating bipolar disorder. Chronobiological treatments such as bright light therapy may be combined with pharmacotherapy to enhance therapeutic effects, reduce adverse side effects, and optimize treatment in patients with seasonal and nonseasonal bipolar disorder.

Influence of season and latitude in a community sample of subjects with bipolar disorder

OBJECTIVE

To report on the prevalence of seasonal bipolar disorder (BD) and the impact of latitude in a community sample in the province of Ontario.

METHOD

This study used the telephone-administered Depression and Seasonality Interview. Exact latitude was determined for each participant.

RESULTS

Overall, 14 of 62 (22.6%) subjects with BD had the seasonal subtype of BD. Latitude did not appear to influence the proportion of subjects with the seasonal subtype.

CONCLUSIONS

We identified a seasonal pattern of illness in a proportion of subjects with BD.

Seasonal variation of mixed and pure episodes of bipolar disorder

BACKGROUND

Although seasonal patterns of manic episodes have been reported, the seasonal variation of mixed states of bipolar disorder has received little attention. In the current report we address that concern as well as the overall seasonality of manic episodes.

METHODS

The seasonal pattern of 304 psychiatric hospital admissions for treatment of mixed or manic bipolar episodes over a 3-year period were analyzed employing two definitions of mixed manic states: DSM-III-R and an ROC derived definition.

RESULTS

The frequency of all manic episodes combined peaked in early spring, with a nadir in late fall. Pure manic admissions showed a similar pattern. Mixed manic admissions had a significantly different pattern, with a peak in late summer and a nadir in November. The differences between pure and mixed manic admissions were demonstrated with the use of the ROC definition for mixed states.

LIMITATIONS

Effects of medications and medication non-compliance may dampen natural seasonal patterns of episodes.

CONCLUSIONS

The different seasonal pattern of mixed and pure manic episodes support the separation of mixed episodes as a distinct clinical subtype.

Does the weather influence dementia admissions?

BACKGROUND

There is currently no literature on the relationship between weather parameters and admissions of organic brain syndromes such as dementias. In this present study we aimed to examine the effect of weather parameters such as relative humidity, sunshine hours, diurnal variations in temperature and rainfall on dementia admissions in North Cheshire.

METHOD

Daily number of hospital admissions of dementias and other diagnoses in North Cheshire was analysed in relation to meteorological data, which were measured at the nearest meterological office to the study population.

RESULTS

The study found no evidence of any statistically significant association between weather parameters and dementia admissions. There was a weak, lagged inverse relationship between dementia admissions and relative humidity and a positive association with diurnal variations in temperature within a week of admission. However, neither finding achieved statistical significance.

CONCLUSION

The study is the first in currently available literature on the subject and may therefore provide a base reference for future studies. The interesting observation relating to relative humidity and diurnal variations in temperature is unexpected and may suggest further research.

Seasonality of manic depressive illness in Canada

OBJECTIVE

The objective of the study was to determine if a seasonal pattern existed for hospital admissions of manic depressive illness to a Ontario provincial psychiatric hospital.

METHOD

Admission records were reviewed for the 75 year period of the study. In the analysis factors including: mood state on admission, gender and the influence of psychotropic medications were considered.

RESULTS

For mania and depression there was no statistically significant seasonal pattern of admissions. For mixed state admissions peaked in the summer.

CONCLUSIONS

The results of this study contradict the seasonal pattern traditionally reported in the literature. The limitations of this study, which include changes in diagnostic criteria over time and admission date not identical to onset of affective episode, need to be acknowledged.

Seasonal influences on admissions for affective disorder and schizophrenia in Ireland: a comparison of first and readmissions

Although genetic and environmental factors operating before or around the time of birth have been demonstrated to be relevant to the aetiology of the major psychoses, a seasonal variation in the rates of admission of such patients has long been recognised. Few studies have compared first and readmissions. This study examined for seasonal variation of admission in the major psychoses, and compared diagnostic categories by admission status. Patients admitted to Irish psychiatric inpatient facilities between 1989 and 1994 with an ICD-9/10 diagnosis of schizophrenia or affective disorder were identified from the National Psychiatric Inpatient Reporting System (NPIRS). The data were analysed using a hierarchical log linear model, the chi-square test, a Kolmogorov-Smirnov (KS) type statistic, and the method of Walter and Elwood. The hierarchical log linear model demonstrated significant interactions between the month of admission and admission order (change in scaled deviance 28.77, df = 11, P < 0.003). Both first admissions with mania, and readmissions with bipolar affective disorder exhibited significant seasonality. In contrast, only first admissions with schizophrenia showed significant seasonal effects. Although first admissions with mania and readmissions with bipolar disorder both show seasonality, seasonal influences appear to be more relevant to onset of schizophrenia than subsequent relapse.

Seasonal influences on admissions in schizophrenia and affective disorder in Ireland

Although the seasonal patterns of admissions of affective disorder have been extensively studied, less attention has been given to the seasonal admission patterns of schizophrenia. The traditional method of aggregating the data over a study period, rather than analysing by year of admission may obscure potentially relevant fluctuations in the seasonal pattern. We examined the year-to-year variation in the admission patterns of schizophrenia and affective disorder in Ireland. Using the National Psychiatric Inpatient Reporting System (NPIRS), individuals admitted with an ICD-9/10 diagnosis of a first episode of schizophrenia or affective disorder during the 6-year period 1989-1994 were identified. Seasonal variations in their admission patterns were examined statistically and graphically. There was a significant seasonal variation in the monthly admission patterns of both schizophrenia and affective disorder. This pattern was more marked for individuals with affective disorder. However, the seasonal pattern was not constant from year to year, particularly for schizophrenia.

Seasonality of mania: a Tasmanian study

OBJECTIVE

The aim of the study was to examine the seasonal incidence of mania in a new Southern Hemisphere location.

METHOD

Using the Tasmanian psychiatric database, monthly admission rates were compared with expected admission rates for mania for the period 1983 to 1989. ICD-9 criteria for mania single episode (296.0) and mania recurrent episodes (296.1) were used, excluding individuals with a bipolar disorder (296.4 to 296.89).

RESULTS

One thousand three hundred and twenty-eight persons were admitted during this period. There was a significant monthly variation with admissions occurring most commonly in the summer, but this was not consistent during the seven year period.

CONCLUSIONS

There was a statistically significant but inconstant summer excess. The inconstancy of the finding suggests that the phenomenon is not a simple consequence of light duration, and closer examination of these inconsistencies may lead to further elucidation of the phenomenon.

Is there a seasonal pattern of relapse in bipolar affective disorders? A dual northern and southern hemisphere cohort study

BACKGROUND

Admission statistics for mania frequently show an increase in the summer. The present two-centre study was designed to test the hypothesis, in a representative sample of bipolar patients, that manic and depressive relapses show a seasonal pattern.

METHOD

Two cohorts of bipolar I patients, one in London, England (n = 86), the other in Dunedin, New Zealand (n = 58), were tracked retrospectively during 1985-88 and prospectively during 1989-91, with the onset of all relapses being carefully dated.

RESULTS

In the London cohort there were 221 episodes of mania and 76 of depression; in the Dunedin cohort there were 201 of mania and 61 of depression. No consistent seasonal pattern of mania was detected in either centre. There was an autumn preponderance of depressive episodes in both centres.

CONCLUSIONS

Relapse of bipolar depression, but not of mania, appears to be determined in part by seasonal factors.

Circannual and menstrual rhythm characteristics in manic episodes and body temperature

Most reports in the literature deal with groups when summarizing the timing of affective disorders along the scale of the year and the menstrual cycle. In order to look for any regularity in timing of manic episodes in a single individual along these two time scales, a woman with a history of mania only, caused by schizoaffective disorder and on maintenance therapy with thioridazine hydrochloride self-measured basal body temperature daily and recorded onset and duration of manic episodes for 11 years. Statistically significant rhythms were found in body temperature with periods equal to the menstrual cycle and the year, with acrophase (highest values) during the luteal phase and winter, respectively. The timing of 11 manic episodes was not random but occurred during distinct portions of the menstrual cycle and the year. Most manic days occurred near menstruation or during the follicular phase of the menstrual cycle (up to ovulation) and between December and May (winter-spring). A temporal schedule for psychopharmacological treatment designed from individualized, longitudinal records that adjusts daily dosages according to both time of year and stage of menstrual cycle might alleviate or minimize the occurrence, magnitude and/or duration of mania and possibly other affective disorders that are found to be associated with underlying biological periodicities.

Seasonality of admissions in the psychoses: effect of diagnosis, sex, and age at onset

A summer peak was found in first admissions to hospitals in England and Wales between 1976 and 1986 for both affective psychoses and schizophrenia, but not for neurotic conditions or personality disorders. There was no significant relationship between age at first admission and season of admission. The summer peak was most prominent for mania, where it was present in both sexes; for schizophrenia, it was present only in females. These findings suggest that schizophrenia in females, and mania in both sexes, have some aetiological or precipitating factor in common.

Season and manic relapse

The episodes of mania occurring in a cohort of 86 patients with bipolar affective disorder were recorded over a 6-year period. Of the 54 patients who had at least 2 episodes, 8 (15%) met our criteria for a seasonal pattern of relapse. There was no particular season in which these relapses clustered. Overall, the time of year of the first recorded episode during the 6-year period did not predict the timing of subsequent episodes.

Mania and seasonality in the southern hemisphere

Admissions for mania over a 9-year period in New Zealand were analysed, including data from four separate regions spanning nine degrees in latitude. A spring/summer peak of admissions for mania was found. The four regions showed marked, unexpected variability in seasonality. Regression analyses were performed to test the association of admissions for mania, in the month of admission and the previous month, with mean daily temperature, day length, hours of bright sunshine and mean relative humidity plus the rate of change of each of these variables.