What are the causes of bipolar disorder? There’s no single known cause of bipolar disorder, but most experts agree that genetics are the primary causal factor. That said, chromosomes and DNA aren’t the only probable causes to consider. The full picture is complicated, and likely involves multiple factors.  

Keep reading to learn about various social, biological, and environmental factors that are thought to contribute to, or exacerbate, this serious but treatable mental health condition.

Genetic Factors

Researchers have found that there’s overwhelming evidence to support the idea that bipolar disorder is often inherited. In fact, there’s a high likelihood that genetic vulnerability is a big contributor to someone’s risk in developing the condition. 

Having first relatives with Bipolar Disorder

According to researchers at the National Institutes of Health (NIH), bipolar disorder is an extremely heritable mental condition — perhaps one of the most — but it’s been incredibly difficult to fully understand in what capacity genetic influence plays a role.

That means people with children, siblings, or parents who have bipolar disorder are more likely to develop it themselves. The same is true with twins. Despite our clear understanding that heredity is involved, scientists haven’t yet been able to discover any specific genetic code that could be responsible for bipolar disorder.

Having another condition that mimics Bipolar Disorder

It’s estimated that 50 million people globally might be affected by bipolar disorder. While we don’t know exactly how heredity plays a role, we do know that it’s polygenic, with incredible potential for overlap in symptoms, with other conditions. 

It’s quite clear that bipolar affective disorder is common, and that it shares certain symptoms with other mental health conditions, which can make an accurate diagnosis more challenging. Some other conditions that can present similarly to bipolar disorder include:

Now, let’s look at some of the biological factors that may contribute to or exacerbate bipolar disorder.

Biological Factors

Research from the National Institute of Mental Health (NIMH) focuses on the neurobiological factors that could potentially cause or worsen symptoms of bipolar disorder. Much of this research is focused on neurotransmitters in the brain, which are chemical messengers that transmit messages from neurons to muscles or between neurons.

Neurotransmitter imbalance

Multiple brain and body chemicals affect mood regulation, and thereby are thought to potentially cause or worsen BD symptoms. Some of these might include: 

In many cases, pharmaceuticals are used to slightly alter these neurotransmitters with hopes of improving bipolar symptoms. However, the mechanisms of action of these medications are not well understood.

Sometimes, they can do more damage than good, exacerbating pre-existing bipolar disorder symptoms, or causing new symptoms all together. Unfortunately, there hasn’t been enough research done for us to fully understand these concepts. Needless to say, much more research is needed in large-scale, randomized human trials.

HPA-axis hyperactivity

So, what causes bipolar disorder? How is HPA-axis hyperactivity connected? According to researchers, depression in bipolar disorder is likely linked, at least in part, to hyperactivity in the hypothalamic-pituitary-adrenal-axis (HPA-axis). Some research has targeted the effects of chronic stress and elevated cortisol on unipolar and bipolar disorders. 

This is a novel area of research, and much more research is needed if we’re to truly understand how the HPA-axis may cause and/or affect BD.

Environmental Factors

Various environmental factors can cause or worsen BD symptoms. Some are more likely to cause depression relative to mania, and others act the opposite way.

“Environmental factors such as life changes, stressful events, homelessness, or where and how a person grows up can trigger or exacerbate this disorder. Although environmental factors are not considered the sole cause of BD, they contribute to it.”

Talkspace therapist Cynthia V. Catchings, LCSW-S

Depression triggers

Some common stressors that might trigger depressive mood episodes in someone who has bipolar disorder could include:

  • Sleep interruptions
  • Everyday stress
  • Illness or injury
  • Sedentary lifestyle
  • Menstruation

Mania and hypomania triggers

Some of the triggers for a depressive episode can also cause a hypomanic or manic episode. However, certain triggers seem unique in their ability to cause mood episodes marked by mania, but not depression, including:

  • Staying up all night 
  • Using recreational drugs
  • Listening to loud music
  • Expressing creativity
  • Romantic interludes
  • Going on vacation

Further, use of antidepressants after giving birth may also trigger a hypomanic episode or manic episode.

Societal Factors

“Societal factors can accelerate the onset or increase the symptoms. Fortunately, these factors can be prevented or eliminated. Therapy can help to accomplish that so the person lives a better life. These societal factors may include adverse life events such as family difficulties, domestic violence, abandonment, or sexual assault.”

Talkspace therapist Cynthia V. Catchings, LCSW-S

Unmanaged stress

Not all mood swings in bipolar disorder are caused by stressful events, but many are. Scientists don’t yet totally understand how stress triggers bipolar episodes, but most believe a stress hormone called cortisol is at least partially to blame.

When we get stressed out, our bodies release more cortisol, which is a steroid hormone produced in the adrenal glands, that alters how the brain communicates and functions.

High cortisol levels

According to researchers, cortisol plays many different roles. It’s important in stress response, inflammatory response, metabolism regulation, and immune function. In small doses, cortisol affects different brain areas — like the amygdala — that control fear, mood, and motivation to protect us. It’s like an internal, autonomic alarm system, and its effects are often referred to as “fight-or-flight” responses to danger.

Periodic small doses of cortisol are natural and healthy, and can, in fact, save our lives. However, when cortisol levels remain elevated, it can cause an array of adverse effects, including:

  • Inability to focus
  • Poor memory
  • Poor digestion
  • Weight gain
  • Depression
  • Headache
  • Anxiety

Stressful events in life and high cortisol levels may contribute to the onset of bipolar disorder symptoms. Once the symptoms are triggered, they may progress. If the bipolar cycle is initiated, then certain biological or psychological processes might act to keep the condition in an active state.

Research about stress and cortisol, and other environmental, social, and societal factors that may cause or exacerbate bipolar disorder symptoms continues.

Understanding More About Bipolar Disorder

Regardless of what causes bipolar disorder, it’s generally considered a lifelong mental health condition. While currently there’s no known cause or cure, with proper diagnosis, online therapy or treatment, and symptom management, it’s very possible to live a happy, productive, life with excellent interpersonal relationships.

If you’ve been diagnosed with bipolar I disorder or bipolar II disorder, become an expert on the subject. Do some deep research so you can begin to understand the nuances of this common yet treatable mental health condition.

Consider scheduling a consultation with a therapist who specializes in bipolar affective disorder. They’ll be able to answer your questions and offer professional advice about effective ways to lessen the frequency and severity of your symptoms.

Your therapist can also teach you various holistic techniques and skills you can use for the rest of your life to better predict, recognize, and manage bipolar symptoms. These may include deep breathing exercises, mindfulness meditation, eating a balanced diet, staying hydrated, exercising regularly, and other easy-to-implement self care techniques.

What are the causes of bipolar disorder? As we’re able to better understand what causes bipolar disorder, there are numerous effective coping strategies — from therapy for bipolar disorder to bipolar disorder medication to self help practices and bipolar disorder natural treatment — that can decrease symptoms and greatly enhance your quality of life. Don’t hesitate to reach out and ask for the help you need dealing with this serious yet manageable condition. You can learn to live with bipolar disorder.