Allostatic load in bipolar disorder: implications for pathophysiology and treatment.

Current literature on the effects of chronic stress in general health converges to the concept of allostatic load (AL). AL is the bodily 'wear and tear' that emerges with sustained allostatic states. In the field of bipolar disorder (BD), AL offers an important clue as to why patients who undergo recurrent mood episodes are clinically perceived as less resilient. In addition, AL helps explaining the cumulative disruptive health effects of intermittent episodes and stressors. Stress- and episode-induced changes in brain regions involved in the emotional circuitry may lead to dysfunctional processing of information, which would render BD patients more vulnerable to subsequent environmental stressors, episodes, and drugs of abuse. Mood stabilizing agents exert opposite effects than chronic stress in neurons, increasing neuroprotective factors what may help to quench the cycle of affective episode recurrence and neural and bodily deterioration. Therefore, AL provides an explanatory link to apparently unrelated findings such as cognitive impairment and higher rates of physical comorbidity and mortality that are observed in the course of BD and further highlight the importance of effective long-term prophylaxis.