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The role of the immune system in developing schizophrenia.

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firemonkee57

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Mar 23, 2009
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8,224
Mental disorders arise from a wide variety of causes, and recently researchers have been increasingly interested in the role of the immune system in causing neurological disorders such as depression and schizophrenia. This field of research, historically known as psychoneuroimmunology, is now referred to as immunopsychiatry, reflecting the understanding that it is not your moodiness that means you will get flu, but the fact that your flu may lead to disruptions in affect and cognition.

Whilst there are many unanswered questions regarding the exact role of the immune system in mental disorders, recent epidemiological and immunological evidence has increased confidence in the importance of this role. Doctor Khandakar and colleagues have elaborately reviewed existing evidence in an article published in this month’s edition of The Lancet Psychiatry. Here they also discuss the mechanisms by which immune responses may contribute to conditions such as schizophrenia, and the implications this has for further research and treatment possibilities.


According to Dr Khandakar: “the article brings together some disparate elements in immunopsychiatry into the possibility of an overarching approach. This approach might contribute to a better understanding of neuropsychiatric disorders both in terms of disease mechanisms and therapeutics”.

So, what does the review tell us?

Epidemiological studies have long noted the link between schizophrenia childhood infections, both in the prenatal period and later on in childhood. A recent example of this cited in Dr Khandakar’s review are findings from the Avon birth cohort study (ALSPAC), where Dr Khandakar and colleagues demonstrated that increased levels of inflammatory markers at age 9 were associated with an increased risk of first-episode psychosis at age 18. Furthermore, other studies have shown that first-degree relatives of individuals with schizophrenia also experience increased rates of autoimmune conditions and that there is a linear relationship between the number of severe infections and risk of developing schizophrenia in individuals with autoimmune disorders.

Taken together, this epidemiological evidence suggests a common pathway between schizophrenia and autoimmunity, probably involving the inflammatory immune response. This is also supported by genetic studies of schizophrenia, which have found robust associations with immune-related genes.

On a more biological level, the review finds that evidence for the link with schizophrenia comes from studies of both the innate and adaptive immune system. The former is the body’s first line of defense, which often acts quickly and in a more general way. The adaptive immune system is able to form memories, and responds to specific threats (for instance, this is how most vaccines work).

The findings from the ALSPAC study are concerned with the innate immune system, as the study looks at the production of markers of inflammation called cytokines. The specific inflammatory marker studied (interleukin 6) is also associated with depression, pointing towards a potential ‘common cause’ for both disorders. Studies in mice have shown the brain effects of raised cytokine levels. This could potentially explain a variety of symptoms in schizophrenia, as well as impaired mood, cognition and perception in other disorders.

A second component of the innate immune system is microglia, which are essentially the resident immune cells of the brain. In healthy individuals they’re not particularly active, but they develop a more active phenotype in response to systemic inflammation. This may lead to the increased expression of certain proteins such as TSPO. This has been confirmed by PET-scanning in patients with a recent onset of psychosis, as well as in patients with acute symptomatic exacerbations. Previously activated microglia can respond more strongly to stimuli, and this is a possible partial explanation for the link between childhood infection and development of schizophrenia.

The role of the immune system in developing schizophrenia. - Department of Psychiatry
 
BillFish

BillFish

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Joined
Sep 12, 2009
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2,388
Mental disorders arise from a wide variety of causes, and recently researchers have been increasingly interested in the role of the immune system in causing neurological disorders such as depression and schizophrenia. This field of research, historically known as psychoneuroimmunology, is now referred to as immunopsychiatry, reflecting the understanding that it is not your moodiness that means you will get flu, but the fact that your flu may lead to disruptions in affect and cognition.

Whilst there are many unanswered questions regarding the exact role of the immune system in mental disorders, recent epidemiological and immunological evidence has increased confidence in the importance of this role. Doctor Khandakar and colleagues have elaborately reviewed existing evidence in an article published in this month’s edition of The Lancet Psychiatry. Here they also discuss the mechanisms by which immune responses may contribute to conditions such as schizophrenia, and the implications this has for further research and treatment possibilities.


According to Dr Khandakar: “the article brings together some disparate elements in immunopsychiatry into the possibility of an overarching approach. This approach might contribute to a better understanding of neuropsychiatric disorders both in terms of disease mechanisms and therapeutics”.

So, what does the review tell us?

Epidemiological studies have long noted the link between schizophrenia childhood infections, both in the prenatal period and later on in childhood. A recent example of this cited in Dr Khandakar’s review are findings from the Avon birth cohort study (ALSPAC), where Dr Khandakar and colleagues demonstrated that increased levels of inflammatory markers at age 9 were associated with an increased risk of first-episode psychosis at age 18. Furthermore, other studies have shown that first-degree relatives of individuals with schizophrenia also experience increased rates of autoimmune conditions and that there is a linear relationship between the number of severe infections and risk of developing schizophrenia in individuals with autoimmune disorders.

Taken together, this epidemiological evidence suggests a common pathway between schizophrenia and autoimmunity, probably involving the inflammatory immune response. This is also supported by genetic studies of schizophrenia, which have found robust associations with immune-related genes.

On a more biological level, the review finds that evidence for the link with schizophrenia comes from studies of both the innate and adaptive immune system. The former is the body’s first line of defense, which often acts quickly and in a more general way. The adaptive immune system is able to form memories, and responds to specific threats (for instance, this is how most vaccines work).

The findings from the ALSPAC study are concerned with the innate immune system, as the study looks at the production of markers of inflammation called cytokines. The specific inflammatory marker studied (interleukin 6) is also associated with depression, pointing towards a potential ‘common cause’ for both disorders. Studies in mice have shown the brain effects of raised cytokine levels. This could potentially explain a variety of symptoms in schizophrenia, as well as impaired mood, cognition and perception in other disorders.

A second component of the innate immune system is microglia, which are essentially the resident immune cells of the brain. In healthy individuals they’re not particularly active, but they develop a more active phenotype in response to systemic inflammation. This may lead to the increased expression of certain proteins such as TSPO. This has been confirmed by PET-scanning in patients with a recent onset of psychosis, as well as in patients with acute symptomatic exacerbations. Previously activated microglia can respond more strongly to stimuli, and this is a possible partial explanation for the link between childhood infection and development of schizophrenia.

The role of the immune system in developing schizophrenia. - Department of Psychiatry
I've read your articles for about 10 years firemonkey, you've posted articles that have suggested it may be anything from a feline virus, to the mother have flu affecting the child in the womb, to an enzyme in the brain.Looking forward to ten more years of potential causes:meanie:
 
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firemonkee57

Well-known member
Joined
Mar 23, 2009
Messages
8,224
For some reason Bill has never liked me.
 
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firemonkee57

Well-known member
Joined
Mar 23, 2009
Messages
8,224
Bill's real name is Alec.
 
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