Stress

Stress, particularly chronic stress, is considered a potential trigger for ME/CFS. It is also thought to worsen ME/CFS symptoms. ME patients are usually advised to avoid stress wherever possible.

Notable studies
Several studies found it is not uncommon to experience major psychological chronic stress (from events such as divorce, bereavement or serious financial worries) in the year prior to developing ME/CFS.

Chronic psychological stress elevates cortisol which suppresses the Th1 antiviral/intracellular immune response and the T-cell response. Chronic stress has also been shown to greatly increase susceptibility to viral infection. This increased susceptibility is not observed after short-term acute stress (periods of stress of less than 1 month duration).

As ME/CFS normally appears after acute viral infection, the presence of chronic stress may weaken immunity and allow a normally mild virus to trigger the serious disease of ME/CFS.