Affective instability is a psychophysiological symptom observed in some psychopathologies. It is a complex construct that encompasses (1) primary emotions, or affects, and secondary emotions, with each category having its own characteristics, amplitude, and duration, (2) rapid shifting from neutral or valenced affect to intense affect, and (3) dysfunctional modulation of emotions. Affective instability is often confused with mood lability, as in bipolar disorders, as well as with other terms. To clarify the concept, we searched databases for the termaffective instabilityand read related articles on the topic. In this article we situate the term within the current affective nomenclature and human emotional experience, explore its psychophysiological features, and place it within the context of psychopathology. We explain why the term can potentially be confused with mood pathology and then define affective instability as an inherited temperamental trait modulated by developmental experience.
1From the THAI Clinic (Dr. Renaud) and Department of Psychology, Douglas Institute, Montreal, Quebec, Canada.
Original manuscript received 2 February 2011; revised manuscript received 15 July 2011, accepted for publication subject to revision 21 February 2012; final manuscript received 6 March 2012.
Correspondence: Suzane M. Renaud, MD, Douglas Institute–THAI, 6875 boulevard Lasalle, Pavillion Newman, Montreal, Quebec H4H 1R3, Canada. Email:smrenaud@aei.ca
