Loading...

Follow A Psychiatry Blog by Justin Marley on Feedspot

Continue with Google
Continue with Facebook
or

Valid
Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

Following on from the previous posts, I’ve taken a look at the extant literature on the relationhip between mood and latitude. Doing a search of pubmed with the search term “mood and latitude” retrieved 500 results. I have included the results that I found of interest below. In the previous post, I have outlined a model of the relationship between one aspect of mood and latitude and this is relevant in terms of reviewing the studies.

The researchers in this 1991 New Zealand study across 9 degrees of latitude found a peak for admissions for mania during the Spring and Summer and found variation according to latitude.

This 2017 Japanese study found a relationship between latitude and hyperthymic temperament. This 2015 study by the same group found evidence that temperature mediates the above relationship. This 2014 study by the same group found evidence that daylight maintained hyperthymic temperament in a dose dependent way. The same group found an effect of lower latitude on inducing hyperthymic temperament in this 2012 study.

The researchers in this study postulate the secondary hypothesis mentioned in the previous post in a simplified form, namely that latitude modifies the course of Bipolar Disorder. They provide evidence of an increased prevalence of manic episodes compared to depressive episodes in 439 subjects in India. The results are intriguing but as per the previous post, it is likely that temperature is a confounding factor.

This 1995 Italian study looked at 543 self-reported surveys of seasonality in mood and did not find a relationship with latitude. The researchers in this 2009 Finnish study did not find a relationship between Beck Depression Inventory scores or Global Seasonality Score with latitude. The researchers in this 2003 Canadian study did not find an effect of latitude on seasonal variation in Bipolar Disorder.

There are a number of polar studies. This 1995 study looked at 119 people who stayed in Antarctica over the winter and found an increase in global depressive symptoms. The researchers suggested that social isolation played a role.  The researchers in this study looked at 91 people in Antarctic research stations. They found evidence that sleep was affected by daylight hours and this was linked to a delayed effect on mood. This 2014 study looked at 162 adults in Tromsø, Norway (at an Arctic latitude but also a coastal city warmed by the Gulf stream). The researchers found that Depressive symptoms modified the adaptation of the sleep cycle to the daylight conditions. Tromsø, Norway was compared with Accra, Ghana in this 2012 study. Daylight hours were linked to mood in the Norwegian city.

In this 2010 Plos One study, the researchers looked at Google searches across a large number of geographical locations. They found that higher latitudes were associated with a larger seasonal variation in searches. They found that seasonal changes in temperature were strongly correlated with mood-related search terms.

There are studies investigating secondary factors (a few of which could be potential confounders in studies investigating the primary relationship). Thus these researchers identified a relationship between sleep duration and latitude in Chile. Latitude was found to be associated with Vitamin D deficiency in this study. The authors of this 2012 paper look at the effects of residence in the Arctic or Antarctic, identifying the profound effects of prolonged or absence of daylight at these latitudes. These include cardiovascular and metabolic effects. The researchers in this 2014 GWA study looked at photoperiod adaptations according to latitude and suggest a link with neuropsychiatric conditions. The researchers in this 2007 study commented on the effects of latitude on comorbidity of Seasonal Affective Disorder with Schizophrenia. The authors here, note a latitude hypothesis for Seasonal Affective Disorder. The researchers in this 2000 Norwegian study found that seasonal variation in episodes of violence was modified by latitude.

Conclusions

Reiterating the primary hypothesis that at a higher temperature Bipolar Depression may switch to Mania, there is evidence for and against this hypothesis above. The conditions in the polar regions are atypical not just because of the temperature but also the daylight conditions, being at times considerably extended and at other times absent. In terms of mood, the polar conditions are likely to modify mood in a very different way to the primary hypothesis. In the poles, sleep is modified by the extreme daylight conditions with a possible secondary effect on mood. The primary hypothesis is likely to apply to much higher temperatures, perhaps 30 degrees Celsius and above and might also be dependent on the rate of increase in temperature. There are some interesting results above including the Japanese studies on temperament which may support the hypothesis. However, the hypothesis would benefit from a rigorous assessment, collecting data on all of the relevant variables.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

In the previous post, we looked at the hypothesis that increasing environmental temperature synchronises desynchronised circadian rhythms in Bipolar Depression. As a hypothesis, this would need to be investigated to accumulate the evidence to either confirm or refute this.

We know that maximum environmental temperature decreases on moving from the equator to the poles. Therefore a secondary hypothesis might be that the prevalence of Bipolar Depression might decrease on moving from the equator to the poles. There are a number of other factors however that would likely invalidate such a hypothesis or else would make it difficult to investigate which I will cover below.

Factors Interacting with Environmental Temperature and Latitude

There are two important factors that influence the environmental temperature at a given latitude – continentality and altitude.

The term continentality refers to the effects of a continent on climate – specifically exemplified by temperature variation. The sea stabilises environmental temperature (evaporation being an effective method of dispersing heat). Moving away from coastal areas, further inland will be associated with an increasing variation in environmental temperature. Continentality was initially characterised by Alexander Von Humboldt. There are other factors that influence this relationship including the presence of mountain ranges between the land and sea.

Another important factor is altitude again characterised by Alexander Von Humboldt. The higher the altitude, the lower the temperature. This is a little bit of a simplification as there are a number of other factors that influence this relationship. Here is a neat post outlining a simple model of the relationship between altitude and temperature along with a description of modifying factors.

Modification of the Environment

People adapt to their environment – the ability to adapt to the environment is an important evolutionary driver. It should therefore come as no surprise that people are very good at stabilising (indoor) environmental temperatures.  If we take a step back and look at whether latitude influences mood via environmental temperature, air conditioning and other environmental modifications are likely to confound this. The effects of changes in temperature will still be experienced even with these adaptations in most cases as the modifications are not perfectly efficient. Nevertheless measuring the external temperature will give a potentially misleading picture of the environmental temperature for indoor workers. Therefore in terms of selecting populations to explore these phenomenon, outdoor workers may be more likely to experience the effects of changes in environmental temperature.

From Biology to Hospital Admission

A number of registry studies often include hospital admissions with diagnosis. I mention registry studies as they are a good way to obtain big data sets to support an examination of the relationship between variables.

However, if we are looking at a simple biological relationship – between mood and environmental temperature, a simple measure such as hospital admission is many steps removed from biology.

Firstly let us consider the biology. Returning to the hypothesis that in Bipolar Depression a switch to Bipolar Mania is more probable with a higher environmental temperature. If this phenomenon exists, then let us suppose that there are X instances of this at any given time.

In order for us to be able to identify this, we then need the biological phenomenon to be translated into a clinical interpretation. This would require that the person comes to the attention of services, that the episode is promptly identified and correctly diagnosed. Let us suppose that Y cases come to the attention of services and receive a diagnosis.

Y = aX

where a is a clinical identification coefficient

The clinical identification coefficient would vary between different regions according to factors such as the configuration of local services, health seeking behaviour and factors affecting health seeking behaviour (e.g. the prominence of the symptoms).

Once identified clinically, there may be a large number of factors determining whether hospital admission is required. Let us say that Z is the number of admissions, then

Z = bY

where b is the admission coefficient

The admission coefficient would be influenced by the number of hospital beds, configuration of local community services, clinical evaluation of severity and a number of other factors.

On moving from biology to clinical identification to hospital admission, there are a number of transformations of the population size which are determined by various factors. By simply looking at hospital admissions, the transformations may prevent us from clearly seeing the effects on biology.

Cyclical Patterns

The primary hypothesis results from a consideration of circadian rhythms but we should also consider the cycles of environmental temperature. The pattern of morning stability of temperature with an increase later in the day and decrease at night reflects the circadian rhythm. During the daytime, the sun heats the ground increasing the surface temperature and the heat is radiated back from the ground with a cooling through the night. There is a diurnal temperature variation. By simply taking single snapshots of environmental temperature and another variable (e.g. body temperature), we will miss the nuances of this relationship and potentially the phenomenon under investigation.

Human Limits

If we are looking at the effects of extremes of temperature, we should factor in whether these are likely to be realistic. Take polar research stations for instance. The temperatures at the poles are so cold that human survival is not possible unless the person is shielded from the environmental temperature by extreme environmental modifications. Under these circumstances, the results may be unexpected. A very low  temperature of -89.2 degree Celsius was recorded in Antarctica. This is significantly below the average body temperature (approximately 125.7 degrees Celsius below). On the other hand, the highest recorded temperatures on Earth are between 50 and 70 degrees Celsius although higher values are possible theoretically. These values differ from the average body temperature by between approximately 13.5 and 33.5 degrees Celsius. This is a much smaller difference than that recorded in Antarctica.

Summarising – for cold conditions, the coldest places in the world are so cold that humans can survive there only by creating completely artificial environments. These environments prevent us from seeing the effects of environmental temperature on the human body. On the other hand, the hottest places on Earth are not so different from the average body temperature although they are still sufficient to make them almost uninhabitable. Thus if we were to select regions of interest for such a study we would have to exclude a number of the very coldest areas on the planet and some of the hottest places.

Towards a Final Model

So if we were to investigate the primary hypothesis that higher environmental temperatures are likely to synchronise desynchronised circadian rhythms in Bipolar Depression and how this links in with latitude we would have to restrict the variables. We would need to select populations of outdoor workers and if there are outdoor workers then it would mean that the conditions are suitable for outdoor working although we should be careful to select for suitable environmental temperature limits. We would need to select locations according to latitude, continentality and altitude.

Then importantly we would need to measure variables which are as close to the biology as possible whilst being clinically relevant. Self-rating measures of mood would be needed, clinically validated diagnoses and identification of Depression and Mania. There should be good datasets on daily body temperature measured through the course of the day for all days of interest. We should also have climate data for all the days of interest. Such an investigation would not be well suited to retrospective collection of demographic data but would need to be prospective, multicentre albeit with small numbers and recording many variables several times on a daily basis.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

Mare Lõhmus has written an interesting paper on the biological links between mental illness and heat. The paper covers a broad range of topics relevant to this central relationship. Lõhmus looks at neurotransmitters as well as neuroimaging studies and the link with sleep. In terms of sleep, Lõhmus cites hot chamber studies revealing a reduction in slow wave and REM sleep with high temperatures and also suggests there may be a distinction between the effects of the timing of heat on sleep. Lõhmus also looks at the historical record including the European heatwave of 2003 and research looking at the New York State Psychiatric Hospital between 1950 and 1983.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

This paper by Nikitopoulou and Crammer was published in the BMJ in 1976. This is a very nice, simple study involving ‘six manic-depressive patients‘. The body temperature was measured with ‘clinical thermometers, which were left for at least three minutes in the axilla‘. The researchers examined changes in body temperature in the patients, who experienced a spontaneous switch from one state to another. Thus the patients acted as their own controls. The researchers analysed the diurnal variation in body temperature in both manic and depressive phases.

What they found was very interesting. The normal course of temperature change is for some stability in the morning with a gradual increase in the afternoon. This was observed in the manic phase. However in the depressed phase, ‘the temperature dropped when the patient got up‘. The researchers therefore distinguish between the circadian rhythm for temperature in depression and mania.

They interpret this in terms of two circadian rhythms in mammals, one entrained to dawn and the other to dusk. The researchers also comment earlier in the paper on the role of Sertraline and Noradrenaline in the circadian rhythms. The researchers hypothesise that there is a desynchronisation of these two circadian rhythms may result in some of the experiences in Depression.

Looking at the previous paper covered in this post, it is interesting to speculate on whether a high maximum environmental temperature is sufficient to synchronise two circadian rhythms (bearing in mind that the previous paper showed some evidence for a transition from depressed to elevated mood with high maximum environmental temperature). If this were the case, it would imply the converse – that lowering the maximum environmental temperature would increase the probability of a desynchronisation of the circadian rhythms.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

According to one study, mood in people with Bipolar Disorder is affected by temperature. Bullock and colleagues published an open access paper in PLOS One. The authors note that various studies have examined seasonal changes in mood and note a seasonal descriptor in DSM-V for Bipolar disorder. The authors note that there have been conflicting results.

On the basis of their study, they suggest that it temperature is an important variable that influences mood. They included people with Bipolar I without significant comorbidity using a self-reported measure of mood – the Chrono record and correlating data with metereological records.

In terms of the Chrono record, a self-reported measure would be a proxy for switches in mood as this would require a clinical evaluation. Nevertheless it is a useful proxy measure in terms of generating hypotheses.

The authors note that

A 1° increase in the maximum temperature was associated with a 17.5% increase in the odds of a transition from depressed to manic mood on average

The authors did not find a similar relationship for switching from ‘normal’ mood to what they term ‘manic’ mood although just to reemphasise the self-reported measure may not be the same as a manic episode.

Other findings related to switching from elevated to depressed mood, the effects of sea-level pressure and sleep. Hours of sunshine didn’t seem to play a significatn role

The temperature hypothesis is a simple and elegant finding. As there were a large number of variables that were being investigated due caution should be exercised and replication would be important. If this holds, it is a very important finding.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

In the previous post, we looked at a study by Åström and colleagues. The researchers found an excess of mortality in many subpopulations during heatwaves and this included psychiatric subpopulations. There are a number of factors which play a role in how these findings might be interpreted although the authors discuss how this can information can help to prepare for heatwaves. The factors that may play a role include how populations adapt to heatwaves over time, the average temperature (compared to the temperature in a heatwave), the temperature during the heatwave, the humidity, the response of the health economy, the utilisation of health services as well as the structure of the health economy.  The other point to consider is that there are different definitions of heatwaves.

Looking at humidity (albeit in relation to cardiovascular mortality), these researchers combined temperature with humidity to create a heat index. They found that

‘females, elderly people, and outdoor workers have higher vulnerability levels in regard to a high heat index’

One UK study found an increased number of mental health related A&E visits together with admissions when looking both at heatwaves and high ambient temperatures. The same authors did not find an increase in utilisation of community mental health services. The authors of this study note that there are current knowledge gaps and that

Mental health impacts should be incorporated into plans for the public health response to high temperatures, and as evidence evolves, psychological morbidity and mortality temperature thresholds should be incorporated into hot weather-warning systems

One study examined heat associated excess mortality (although distinct from heatwaves) from 1900 to 1948 and 1973 to 2006 in New York City. The researchers found that the excess mortality decreased in the second period. The authors suggested that the population had adapted over time.

The effects of heat alerts in 20 US Cities between 2001 and 2006 was examined in this paper where the authors recommended an exploration of interventions and communication strategies in addition to heat alerts.

In Gujarat, India in 2010 there was a heatwave with a peak temperature of 46.8 degrees Celsius. The researchers found excess deaths in the population (a 43% increase) but particularly in women during this period.

NHS choices have provided useful information resources here.

Appendix

What is the Effect of Heatwaves on Psychiatric Populations ?

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

At the moment there is a heatwave in the UK. The UK government has announced an Amber alert. A natural question for a Psychiatrist to ask, is what is the relationship between heatwaves and mental illness?

I came across this paper by Oudin Åström and colleagues. The researchers look at the effects of a heatwave in Rome, Italy and Stockholm, Sweden on the mortality of the population aged 50+ and then analyse this according to the subgroups.

In terms of heatwaves, the authors define this as

a heat wave as two consecutive days with temperatures exceeding the 95th percentile of the MAT

where MAT is the Maximum Apparent Temperature.

The researchers used population registers and looked at the diagnosis on admission in order to classify subpopulations.

There was found to be an increase in mortality across different subpopulations during heatwaves.

What I found particularly interesting were the mortality rates for psychiatric subpopulations. In Rome, the relative risk of mortality (heat wave days v non heat-wave days) in the Psychiatric subpopulation was 1.21 (95% CI 1.06-1.38) and 1.28 in women. In Stockholm the relative risk was 1.33 (95% CI of 1.1-1.61) and in women was 1.40.

Whilst the authors emphasise the importance of using these results to prepare for future heatwaves, the aetiology for the increase is unclear.

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

(14 June 1864 – 19 December 1915)

Alois Alzheimer was a Psychiatrist who identified Alzheimer’s Disease, the pathology that leads to Alzheimer’s Type Dementia. His findings were instrumental in transforming the understanding of Dementia. To put this in a historical context, the interested reader is directed to this paper outlining how the understanding of cognition in older adulthood has changed over the past two thousand years.

Alzheimer was born in Marktbreit in Germany (the house where he was born is now a museum).  He studied medicine in Berlin and then at the Würzburg University and his lecturers had included Westphal, Corti, Leydig and Waldeyer. Alzheimer qualified in 1887 and then worked as both a Psychiatrist and Pathologist in Frankfurt. Alzheimer worked with Nissl (who had developed Nissl staining) and Sioli. Together they transformed the practice in the Institute in which they were working, avoiding restrictive practices and engaging patients in bath therapy and dialogue. Alzheimer later moved to  Heidelberg where he was mentored by Emil Kraeplin, a prominent Psychiatrist of the nineteenth century.

One of Alzheimer’s patients was a 51-year old lady with young-onset Dementia. When she died, Alzheimer undertook a post-mortem study. Alzheimer presented his findings at Tübingen and the following year published his seminal paper.

In summary Alzheimer studied with many noted psychiatrists and pathologists and had developed significant expertise in both areas. He gained significant clinical experience and innovated in service delivery. His histopathological studies extended to many neurological and psychiatric conditions and he integrated clinical and histopathological findings.

Previous Posts in the Series

John Cade

Jean-Martin Charcot

William Cullen

Eleanor Fleury

Anna Freud

Sigmund Freud

Alfred Garrod

Karen Horney

Karl Jaspers

Carl Jung

John Locke

Franz Mesmer

Nossrat Peseschkian

Johann Reil

The Complex Interplay Between Past Psychiatrists

Professor Pariante on Psychiatry

Index: There are indices for the TAWOP site here and here

Twitter: You can follow ‘The Amazing World of Psychiatry’ Twitter by clicking on this link.

TAWOP Channel: You can follow the TAWOP Channel on YouTube by clicking on this link.

Responses: If you have any comments, you can leave them below or alternatively e-mail justinmarley17@yahoo.co.uk.

Disclaimer: The comments made here represent the opinions of the author and do not represent the profession or any body/organisation. The comments made here are not meant as a source of medical advice and those seeking medical advice are advised to consult with their own doctor. The author is not responsible for the contents of any external sites that are linked to in this blog.

Conflicts of Interest: *For potential conflicts of interest please see the About section

Read Full Article
  • Show original
  • .
  • Share
  • .
  • Favorite
  • .
  • Email
  • .
  • Add Tags 

Separate tags by commas
To access this feature, please upgrade your account.
Start your free month
Free Preview