If you’re on this page, you, or someone you love, may have been diagnosed with bipolar disorder. That can be scary, as bipolar is a serious mental condition that short-circuits the brain’s ability to think clearly and causes states of extreme ups and extreme downs, called mania and depression. Your mind is probably reeling, and you’re chock full of questions. One of the first you’re probably asking is: Where did this come from? Did I do something to cause this? Many people with bipolar wonder the same thing. We’ve the answers you need.
What is Bipolar Disorder, Exactly?
Everybody goes through mood ups and downs, but in bipolar disorder, a person experiences pronounced episodes of lows (depression) and highs (mania).
These mood swings can interfere with day-to-day life, making it hard to do right by your relationships, function efficiently at your job, and take care of your own everyday needs—getting the laundry or grocery shopping done, getting enough sleep, that sort of thing.
The good news is that treatment can make a huge difference.
In order to be diagnosed with bipolar, you must have experienced at least one episode of mania or hypomania, a milder form of mania. If that’s the case, then docs can delve deeper to find out which of the four types of bipolar you have:
Bipolar I: This is the most severe type. People with bipolar I typically experience severe cycles of mania and depression.
Bipolar II: Bipolar II comes with that milder form of mania, hypomania, as well as the typical depressive episodes.
Cyclothymic Bipolar: Both the depression and mania are on the mild side.
Unspecified Bipolar: Here, the symptoms are like bipolar, but they’re not frequent or lengthy enough to warrant the diagnosis of one of the other types of bipolar.
Is There One Cause of Bipolar Disorder?
That’s a very common question, and the short answer is no. There is no one thing that causes or leads to bipolar disorder.
Genetic, psychological, environmental, and social factors are at play, though experts presume that bipolar disorder can primarily be blamed on biology — more specifically, the pre-frontal cortex, the part of the brain that’s in charge of processing emotions, learning and memory, reasoning, and judgment.
Let’s look a little deeper into the probable causes of bipolar disorder.
Genetics almost undoubtedly plays a part in bipolar disorder. While an exact gene or combo of genes has yet to be identified (if it even exists), research has shown that two genes, CACNA1 and ANK3, may make you more susceptible to developing the disorder.
But not everyone with bipolar disorder has these two genes, so they’re unlikely to be the primary cause of the disorder.
In addition to those genes, researchers suspect there could be various other small variations in genes that are involved as opposed to a large variation in a single gene. Also, this could not be the case—experts just don't know yet. Lots to still learn!
What we do know with some certainty is that genes are somehow involved, since bipolar tends to run in families. Research shows:
- The lifetime risk of the average person developing bipolar is 2%.
- If you have a first-degree relative who has the condition (mother, father, brother, or sister), your risk is now 5-10% , which is more than double the average person.
- If you have an identical twin who has the condition, your risk of developing it as well jumps to between 40% and 70%.
Bipolar affects men and women in equal numbers. There are some differences:
- Women are more likely to experience rapid cycling, which means they’ll go through many mood ups and downs in a given year.
- Women experience mixed episodes, when mania and depression happen at the same time or in quick succession without a stretch of time in between, more often than men.
- Women are more likely to suffer from bipolar II than men.
- While the average age of developing the disorder is around 25, men often develop the disorder at a younger age than women.
- Though not absolute, men often show more symptoms of a manic episode first, while women usually experience a depressive episode initially.
Through brain scans like functional MRIs, experts have found subtle differences in the brains of people with bipolar. It’s unclear whether these changes are the reason why people develop the disorder, or the changes are because of the disorder.
Here are the key differences:
- Overactive in people with bipolar disorder: the amygdala, which is crucial for processing emotions
- Underactive in people with bipolar disorder: the hippocampus, which plays a crucial role in learning and memory, as well as other vital neurons in the prefrontal cortex that relate to planning complex cognitive behavior, personality expression, decision making, and moderating social behavior
This overactive/underactive situation may be why, during a manic episode, the executive function is impaired while emotions are heightened and uninhibited.
Other imaging tests have led experts to theorize that in people with bipolar, it’s possible that something may have happened to the brain in its early development that results in decreased connections among prefrontal networks and limbic structures, especially the amygdala.
In other words, the fine-level connections in parts of the brain are disrupted and somehow those circuits are misaligned or misfiring.
Age of Father at Conception
It sounds wild, we know, but stay with us here. In one study of over 6,800 people with bipolar disorder, after adjusting for several possible contributing factors (such as parental education, income, and history of psychiatric hospitalization, as well as maternal age), fathers who were in their mid 50s and older were six times more likely to have a child with bipolar disorder than men who were in their early 20s.
Any Other Factors That May Contribute to Developing Bipolar?
As we described earlier, experts have good reason to believe that biology is mainly to blame for bipolar disorder—in particular, specific areas in the brain that over- or under-produce particular brain chemicals. However, it’s possible that certain environmental factors may trigger the disease in those who were already susceptible. That’s not to say that you’d get the disease if you weren’t predisposed to it in the first place. But it’s conceivable that bipolar could lie idle, only activating if certain factors arise. These may include:
- Stressful events. Highly disturbing happenings like divorce, experiencing a death of a family member, or losing a job can set off a bipolar incident. Also, people who’ve experienced a traumatic event like sexual or physical abuse, neglect, or death of a parent early in life have an increased risk of bipolar later.
- Sleep disturbances. Research found that 25% to 65% of people with bipolar had experienced a “social rhythm disruption”—science speak for daily routines that can impact the sleep/wake cycle—before an episode of mania.
- Drugs and alcohol. More than 60% of people with bipolar disorder abuse alcohol or drugs. The classic chicken/egg questions arises here (“which came first?”), and the answer is, it’s likely bidirectional. That is, people with bipolar take more risks, which allows for more alcohol and substance abuse, which may lead to brain and social stressors that increase the likelihood of the disorder.
Suffice it to say, there is a lot we still don't know about the causes of bipolar disorder. But that doesn’t make it any less real for the people experiencing it. If you think you or someone you know might be suffering from bipolar, check out our Bipolar Symptoms page to learn more about what this illness looks like.