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Is Bipolar Disorder an Inflammatory Disorder?
Bipolar disorder is a complex disorder that interacts with many systems in the body.
For decades, bipolar disorder and other psychiatric disorders were thought to be caused by issues with monoamines (neurotransmitters and neuromodulators like serotonin and dopamine). And while research has been focused in this area, no overall picture of psychiatric disorders has been provided by this approach. This doesn’t mean that monoamines don’t play a role in these disorders—maybe even a big role—but it likely means there are other systems at work as well.
One of models being considered for further research is that of inflammation. Inflammation is known to interact with the immune system and is implicated in allergic reactions.
Disorders currently associated with inflammation include:
- celiac disease
- rheumatoid arthritis
- autoimmune disease
- and many others
Support for the Inflammatory Model in Psychiatric Disorders
There are common comorbidities in bipolar disorder, such as cardiovascular disease, obesity, and autoimmune diseases that are known inflammatory diseases, suggesting that inflammation may be involved with psychiatric disorders. The reverse is also true: populations with some inflammatory diseases have a greater rate of psychiatric disorders.
The symptoms associated with nonspecific reaction to inflammation are common to depression as well. These symptoms include decrease in appetite, a lack of motivation, cognitive impairment, and neurovegetative symptoms. (Neurovegetative symptoms include sleep disorder, anhedonia, guilt, lack of energy, lack of concentration, psychomotor changes and suicidality.)
Also, inflammatory cytokines (a basic cellular protein communication molecule) have been shown to be abnormal in those with bipolar disorder, major depressive disorder and schizophrenia. (More technical details on research support can be found here.) Additionally, “studies show levels of inflammatory cytokines and interleukins rise during a depressive episode and decline when the depression remits.”
All this support is encouraging, but, of course, it’s still early days in this line of research.
Inflammatory Model Effects on Bipolar Disorder Treatment
This is all to say that medications that affect the inflammatory system in the body may be useful in treating bipolar disorder and other psychiatric disorders. In fact, the inflammatory model may help explain why some of the existing treatments work.
For example, take n-acetylcysteine (NAC), an over-the-counter supplement that has been shown to treat bipolar depression (and other things). NAC both modulates the precursor to glutamate (a monoamine) and reduces oxidative stress on cells. Inflammation increases oxidative stress and so reducing it may be part of how NAC works.
Additionally, a small study found that adding aspirin (a non-steroidal anti-inflammatory, NSAID) to fluoxetine in depression treatment-resistant rats created an antidepressant effect. Another study showed that an NSAID coupled with an antipsychotic or mood stabilizer for people with bipolar depression decreased the time to effectiveness.
According to a Psychiatric Times article, other anti-inflammatory agents have also been shown to treat psychiatric symptoms:
- Adding celecoxib has been shown to exert antidepressant effects in major depression and bipolar disorder as well as treat the symptoms of schizophrenia
- Minocycline, a tetracycline antibiotic with anti-inflammatory properties, has also been shown to mitigate negative symptoms and improve cognitive function in patients with schizophrenia
- Minocycline may also exert antidepressant effects
Now, I’m not suggesting you change up your treatment regimen based on this early science but I am suggesting it’s an area of hope and an area to watch.
Are Psychiatric Disorders Inflammatory-Based Conditions? By Joanna K. Soczynska, Lucia Zhang, Sidney H. Kennedy and Roger S. McIntyre