And yet fatigue is common in people with a history of depression (it occurs in up to 10% of the general population and is much more common in women, who have a higher rate of depression).
And symptoms of fatigue may last well beyond the other symptoms of depression.
A thoughtful assessment begins with an assessment of the nature of the symptoms. Are we talking about trouble initiating any activity (generalized weakness), or trouble concentrating (mental fatigue) or a reduction in the capacity for sustained physical activity (easy fatiguability)? Some people have a mixture of these, but figuring out what type of fatigue is most prominent can be helpful in determining what the cause of the fatigue is.
A careful evaluation for physical causes is in order.
Among causes to rule out are –
- Medications (especially high blood pressure medicines, medicines for sleep, and some antidepressants and mood stabilizers)
- Thyroid disease
- Low cortisol (adrenal insufficiency)
- Chronic kidney or liver failure
- Heart or lung diseases (associated with shortness of breath)
- Cancer (if there is significant unexplained weight loss)
- Infections (mononucleosis, CMV, hepatitis, HIV, parasites, especially if you have been traveling recently)
- Sleep disturbances (obstructive sleep apnea, restless legs, severe allergies)
- Chronic fatigue syndrome (a relatively rare condition with specific criteria)
- Fibromyalgia (associated with tender points on the body)
- Idiopathic (or “Other”)
After a careful history, lab studies and appropriate physical examination, a fair number of people will end up with “Idiopathic Fatigue.”
What can or should be done for them.
A thoughtful evaluation of diet is in order. And assessment of their level of physical activity as well (fatigue can be caused by chronic inactivity, but it can also occur when someone starts overtraining, graduated physical activity is the best approach).
And then it may be time to consider stimulants. A recent review of this topic (“The use of stimulant medications for non-core aspects of ADHD and in other disorders” in Neuropharmacology 2014 [in press]) concluded that the evidence was reasonably strong and consistent that some patients with recurrent depression, and perhaps even some patients with bipolar, might benefit from a trial of methylphenidate or lisdexamfetamine.
Needless to say, this is an experimental treatment that would require thoughtful assessment of the risks and benefits and careful monitoring.