Brain fog is a term for the "woolly" sensation of a physical obstruction to clear thinking in the brain, often extended to apply in general to neurocognitive symptoms experienced by many people who suffer from diseases such as ME/CFS, fibromyalgia, amongst others. Brain fog is thought to represent a psychological response to stress.
It can be symptom manifest of psychiatric disorders such as schizophrenia, bipolar disorder, or clinical depression.
The term brain fog is also often used to describe the relevant symptom or symptoms of inattentive ADHD or resulting from chemotherapy..
Brain fog involves persistent or episodic cognitive dysfunction, and may be associated with forgetfulness, confusion, slowed thinking, distractability, depersonalization, the inability to remember the correct words when speaking or writing (dysphasia or aphasia).
Brain fog is so named because the sufferer can feel like a cloud literally surrounds him or her that reduces the speed at which things can be recognized or clearly seen. Brain fog may promote feelings of detachment (depersonalization), discouragement and depression.
Brain fog can be brought on by upregulated cytokines, neurotransmitter misregulation, or psychological trauma amongst others. Hence it shares common etiology with some mental disorders like depression, bipolar disorder, etc.
There have been no studies to explore the causes of brain fog, but since it shares so many of it's symptoms with mental disorders it's reasonable to assume that brain fog may be due to frontal lobe hypometabolism, or temporal lobe dysfunction which occur in unipolar depression.
Brain fog is not recognized by medical science, and there have been no clinical studies to prove its existence. Some clinicans maintain that brain fog is a form of conversion or somatization disorder.
Since brain fog is very similar to symptoms of mental illness, it's possible that persons who report brain fog are actually suffering from mental disorder including depression, schizophrenia, or bipolar disorder.
In particular brain fog is very similar to the decrease in concentration in depression and the depressive phase of bipolar disorder and thought blocking which occurs in schizophrenia.
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