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Fatigue and cognitive function

Disrupted sleep or poor quality of sleep and pain in themselves contribute to fatigue and impaired cognitive function. The ability to study sleep patterns, but also other brain activity patterns, has helped researchers see other deficits in these illnesses.

Many clinicians working with ME/CFS and FM patients will prescribe medications which can increase alertness and concentration. On the other hand, some doctors don't support their use at all because they say increased firing of certain neurons, over time, may actually damage brain cells.

Therefore, patients and their physicians need to take into account the effect of their fatigue and difficulty with concentration on their daily functioning, ability to work and overall quality of life versus the risks of these types of medications. They should also consider alternative options as there are a variety of supplements used to help promote mitochondrial energy production—these are covered in the Supplements article and Mitochondrial Dysfunction, Post-exertional Malaise and ME/CFS.

Though antidepressants are usually prescribed to help with sleep and pain, some can also provide an energizing/activating effect and improve mental clarity. This is accomplished according to how certain neurotransmitters are inhibited or increased, especially by a group of medications called, selective serotonin reuptake inhibitors (SSRI's) which primarily increase serotonin to the nerves.

Some examples of commonly prescribed SSRIs include Prozac (fluoxetine), Paxil (paroxetine), Lexapro (escitalopram) and Zoloft (sertraline). Weight gain, sexual dysfunction, anxiety and/or sleep disturbance are some of the more frequently reported side effects of these medications. Patients should be closely monitored for worsening symptoms of depression or mood and/ or suicidal thoughts during first weeks of treatment.

One of the older medications used for its activating properties is Wellbutrin (bupropion)—it is defined as a norepinephrine and dopamine reuptake inhibitor and is chemically different from tricylic antidepressants and SSRIs. A higher incidence of seizures has been reported in some patients using Wellbutrin than with other antidepressants.

Another medication in its own class is Provigil (modifinil) originally intended to treat daytime sleepiness found in narcolepsy. It is used to help relieve MS-related fatigue and more recently, to improve mental clarity in ME/CFS and FM. Its mechanism differs from most other stimulants as it primarily targets the part of the brain which keeps people awake. It may disturb sleep in some patients, even though this medication is taken during the early part of the day. The FDA issued a warning in 2007 that Provigil has been linked to serious skin rashes and psychiatric symptoms (i.e. anxiety, mania, or hallucinations) and urged caution if used for patients with a history of psychosis, depression, or mania.

Other stimulating medications are borrowed from Attention Deficit Disorder (ADD), such as Ritalin (methylphenidate) or Cylert (pemoline). Straterra (atomoxetine) is also in this category but is found not to be as stimulating as the older formulas. While they might help some people with concentration, they can also negatively affect mood and raise blood pressure.  Sometimes amphetamines (like Adderall and Dexedrine) are prescribed to patients with ME/CFS and FM to improve concentration, even though initially these type of medications were used to suppress appetite, treat ADD and drowsiness in narcolepsy.

Other medical causes of fatigue

Two potential, underlying sources of fatigue may be an underactive thyroid and/or underactive adrenal glands. The thyroid gland in a number of individuals with ME/CFS and FM may either fail to produce sufficient amounts of thyroid hormones or their bodies make poor use of the hormones that are being produced. This, in turn, can cause fatigue, sluggishness, slowed metabolism and increased risk of iron and B12 deficiency. 

Some doctors will try to improve thyroid function by prescribing  Synthroid, but it is important to realize there are various treatment approaches and interpretations of thyroid tests.

About two-thirds of ME/CFS and FM patients are thought to have low adrenal function which can also cause fatigue, poor response to stress and predispose individuals to recurring infections. Some doctors will prescribe low-dose Cortef (hydrocortisone) to help support adrenal function, but others will regard this treatment as being controversial.

Doctors practicing holistic or integrative medicine may be more familiar and receptive to the newer treatment approaches as well as offer additional ways to help improve fatigue and energy production.  Some commonly used alternative products are reviewed in the Supplements article.