The Kindling Model Revisited

by Kimberly Read

A Review of "Stressful Life Events, Bipolar Disorder, and the 'Kindling Model'," from the Journal of Abnormal Psychology.

In research relating to bipolar disorder, the "Kindling Model" is a theory that holds to the idea that "the first episode of bipolar disorder, whether manic or depressive, is more likely to be associated with major psychological stressors than are episodes occurring later in the course of the illness." In other words, initial depressive, manic or hypomanic episodes may be sparked by a stressful life event, but as the disorder progresses further episodes may occur without any outside triggers. This theory seems to be intuitive and explains the course of bipolar disorders rather reasonably.

However, a recent study published in The Journal of Abnormal Psychology suggests that this model does not fully explain this disorder. In this article entitled "Stressful Life Events, Bipolar Disorder, and the 'Kindling Model'," a group of researchers examined previous research that was specific to the theory of kindling and bipolar disorder. Of the seven research projects previously done, the results are rather conflicting: five support the theory of kindling, two do not and one was inconclusive.

Therefore, this study undertook to improve on previous designs and reach more conclusive results. The general purpose of this study was to "understand the factors related to good versus poor long-term outcomes" and specifically

1. to understand the "exact nature of the relationship between life events and bipolar episodes"
2. to understand "how this relationship changes over the course of the illness"
3. to determine if "major life events play a diminishing role in the onset of new episodes over the course of the illness"

All of the participants in this study had "a definite diagnosis of bipolar affective disorder, type I." This diagnosis was confirmed using the Schedule for Affective Disorders and Schizophrenia - Lifetime Version as well as the Structured Clinical Interview for DSM-IV. Additional criteria relating to the timing of episodes was also used to determine inclusion in the study, and exclusions were made if additional conditions or disorders conflicted with this study. Of the 64 participants ranging from 19-63 years in age, the average age was 36.5 years and 64.1% were female. Marital status as well as educational background varied greatly.

Using a battery of diagnostic and symptom assessment measures, the researchers evaluated the life events of the participants for a three-month period preceding their most recent episode and a three-month period in which the participant was episode-free. They expected to find that the number of episodes would allow them to predict if a participant was in a high, moderate, or low level of stress before the onset of the participant's latest episode. However, the research revealed that this just wasn't the case. "The number of episodes experienced does not appear to have a significant effect on bipolar I patients' reactivity to external stressors."

This study suggests that a "complex relationship probably occurs among age, stress, and the onset of new episodes than cannot be adequately explained by the kindling model." Bottom line is that the findings of this study do not support the kindling model as a theory for the progression of bipolar disorder over the course of a lifetime, but obviously more research is needed.

The above is a review of "Stressful Life Events, Bipolar Disorder, and the 'Kindling Model'," from the Journal of Abnormal Psychology

Authors:

• Stefanie A. Hlastala & Ellen Frank
  University of Pittsburgh School of Medicine
• Jeanne Kowalski
  Harvard School of Public Health
• Joel T. Sherrill
  University of Pittsburgh School of Medicine
• Xin M. Tu
  University of Pennsylvania Medical Center
• Barbara Anderson & David J. Kupfer
  University of Pittsburgh School of Medicine

For Further Study

• The "Kindling" Model
• Does Bipolar Disorder Get Worse Over Time?