Can Trauma Cause Bipolar Disorder?

I was recently asked if trauma can cause bipolar disorder. This isn't the first time I have been asked this question. I think the question often comes from two types of people. The first type is people who have trauma in their past and want to know if it caused their own bipolar. The second type is of people who are concerned that trauma may cause or have caused bipolar in another. I can understand the concerns of these people, so let's dig into the question: can trauma cause bipolar disorder?

What Is Trauma in Bipolar Disorder?

Bipolar disorder is typically thought of as a bio-psycho-social illness.¹ This means that the onset of bipolar disorder is related to biological, psychological, and social (environmental) factors. Trauma in bipolar disorder is considered an environmental (or social) factor.

Environmental factors in bipolar disorder run the gamut from maternal smoking and infection, birth complications, and climate effects. But when looking at whether trauma causes bipolar disorder, we are specifically looking at adverse life effects that the person finds traumatic. Examples of possible trauma include loss of a parent, childhood adversities, or even job loss.² 

Does Trauma Cause Bipolar Disorder?

The thing is, no matter how devastating a trauma might be, some people undergo the trauma and do not develop bipolar disorder while others do. This tells us that trauma alone does not cause bipolar disorder.

However, that does not mean that trauma does not play a role in the development of bipolar disorder. A bio-psycho-social model of bipolar tells us that while trauma may be part of the equation, it's not the entire equation. In my opinion, it's the biological part that people possess that makes a difference between whether trauma helps to cause bipolar disorder or not. Keep in mind that "biological" doesn't just mean that it runs in the family (genetics). It might also mean that a person has a spontaneous mutation or a physical difference in the brain.

If Trauma Doesn't Cause Bipolar, What Does?

Basically, bipolar is so complicated that we don't know what exactly causes bipolar disorder for any individual. The cause of bipolar disorder is combinatorial. In other words, I could write down a list of 50 things that have been tied to bipolar disorder, like a menu, if you will. They could be put in three columns: bio, psycho, and social, and given a calorie count relating to its likelihood of causing bipolar disorder because some items are more closely linked to bipolar disorder than others. Any person could then pick items from the menu, and if those things added together had enough "calories," then the result would be bipolar disorder. Because there are 50 items on the menu, and because you never know how many of the menu items any one person will pick, there's no way to predict even how many permutations cause bipolar disorder, let alone what the permutations may be. (Of course, it's a bit more complicated than that as each menu item affects each individual differently, making even the "calorie count" variable.)

So, looking at things simply, trauma doesn't cause bipolar disorder, but trauma can add to the likelihood of a person developing bipolar disorder if they also have other risk factors. I know that's a bit of a mouthful, but it's the best science can do at the moment.

Sources

1. Bender, R. and Alloy, L., "Life Stress and Kindling in Bipolar Disorder: Review of the Evidence and Integration with Emerging Biopsychosocial Theories." Clinical Psychology Review, January 2011.
2. Aldinger, F. and Schulze, T., "Environmental Factors, Life Events, and Trauma in the Course of Bipolar Disorder." Psychiatry and Clinical Neurosciences, January 2017.