What Causes Bipolar Disorder?
Early intervention is important for people with a family history
Medically reviewed by Elle Markman, PsyD, MPH
There isn’t a single or exact known cause of bipolar disorder. However, research has identified several suspected causes and risk factors that help explain why someone may develop bipolar disorder. These include genetics or family history of bipolar disorder, environmental factors, and brain structural and functioning differences.
This article details the suspected causes of bipolar disorder, risk factors to be aware of, and known brain differences. It also covers what causes worsening symptoms in people with bipolar disorder and other variables that can cause complications.
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Bipolar Disorder Causes
Bipolar disorder is a brain disorder, or mental illness said to be caused by a combination of factors triggering changes in a person’s mood, energy levels, and overall functionality.
Genetics Plays a Role
Bipolar disorder can be considered a high degree of genetic heritability, meaning it is often passed down from parent to child. While several different factors influence someone’s likelihood of developing bipolar disorder, research indicates the lifetime risk of developing bipolar disorder is eight times more likely if you have an immediate family member (first-degree) with the disorder. The risk increases further if you have two parents with bipolar disorder.
Takeaway
Many genes are involved in bipolar disorder, and no single gene is the cause.
Childhood Trauma Contributes to Risk
Childhood trauma or maltreatment in childhood is an environmental risk factor linked to the later development of mental illness, including bipolar disorder. Research has shown a significant association between bipolar disorder and previous physical, sexual, and emotional abuse, as well as physical and emotional neglect.
Does Childhood Trauma Cause Bipolar Disorder?
While there is a link between childhood trauma or maltreatment and bipolar disorder, the exact nature of how or why this happens is still unclear and is the focus of ongoing research.
Related: The Path to Healing After Relational Trauma
Stressful Life Events Affect the Course of Bipolar Disorder
Stressful life events such as job loss, parental loss, divorce, disability, and losing a relative to suicide play their part in the onset and course of bipolar disorder. Research has shown a relationship between recent stressful life events (i.e., within the last six months) and the onset of bipolar disorder manic or depressive episodes in at-risk persons.
Takeaway
There are many reasons why stressful life events occur and whether or not they lead to mental illness. Experiencing negative life events does not mean someone will develop bipolar disorder.
Related: What Is a Manic Episode?
Substance Misuse May Trigger Episodes
Bipolar disorder and substance use disorders are often found together in clinical settings. Research has shown there is a two-way relationship between cannabis, cocaine, opioid, sedative, and alcohol misuse and bipolar disorder. In other words, using substances can trigger manic or depressive episodes or relapse in people with susceptibility to bipolar disorder, and bipolar disorder can increase the risk of developing substance use disorders. Substance use can also lead to misdiagnosis of bipolar disorder rather than be a causative factor, though.
Related: 9 Common Depression Triggers (and How to Manage Them)
Risk Factors for Bipolar Disorder
We know more about risk factors for bipolar disorder than direct causes. Risk factors like genetics, childhood maltreatment, stressful life events, and substance misuse, for example, do not directly cause bipolar disorder. Rather, they contribute to someone’s overall likelihood of developing bipolar disorder.
Risk factors also offer insight into bipolar disorder predictability, so early interventions can be made to reduce the risk of bipolar disorder where possible. Having several risk factors for bipolar disorder does not mean someone will inevitably develop bipolar disorder.
Co-Morbid Conditions
A small number of studies have identified the following medical conditions associated with bipolar disorder. These conditions may be linked to bipolar disorder because they share similar inflammatory and stress-related causes:
Irritable bowel syndrome (IBS)
Asthma
Obesity
Migraine headaches
Traumatic brain injury
Related: List of Mental Illnesses
Bipolar Disorder Brain Differences
Brain structure and function may differ in people with bipolar disorder compared to people without bipolar disorder and to people with other mental illnesses, according to the National Institute of Mental Health.
Specific brain differences are seen in the following areas:
Prefrontal cortex: Responsible for cognitive controls like impulse control and problem-solving,
Subcortical structures: Responsible for hormone production, mood and emotion regulation, and memory.
Medial temporal structures: Responsible for memory.
Difference Between Bipolar I and Bipolar II
Bipolar disorder has subtypes, Bipolar I and Bipolar II. The difference between Bipolar I and Bipolar II is the severity of symptoms, including the severity of mania. People living with Bipolar II are said to experience less severe and shorter episodes of mania, known as hypomania.
Related: The Anatomy of the Brain
What Causes Worsening Bipolar Disorder Symptoms?
Worsening bipolar disorder symptoms can be caused by risk factors for developing bipolar disorder or the onset of a manic or depressive episode. Other causes include:
Environmental factors like stress and sleep disruption
Not taking bipolar medications as directed
Drug and alcohol use
The Role of Medication for Bipolar Disorder
Being unmedicated or stopping pharmaceutical treatment is another cause of symptom relapse and worsening bipolar symptoms. Preventing future mood episodes comes down to taking mood stabilizers like lithium on an ongoing basis and adhering to medication plans. Bipolar disorder will not go away on its own, but with the right treatment, symptoms can be effectively managed.
Other Causes of Bipolar Disorder Complications
Psychological and social factors can cause bipolar disorder complications. These include a lack of social support and family dysfunction. In other words, not having adequate support and understanding from loved ones and caregivers can cause bipolar disorder complications.
Getting Help
If you or a loved one needs help with bipolar disorder or the associated signs and symptoms, contact the SAMHSA National Hotline for treatment and support group referrals at 1-800-662-HELP (4357). If you are having suicidal thoughts, dial 988 to contact the 988 Suicide & Crisis Lifeline and connect with a trained counselor. If you or a loved one are in immediate danger, call 911.
Related: Why Bipolar Disorder Stigma Exists
Summary
There isn’t a single known cause for bipolar disorder. Rather, research suggests a combination of factors contribute to someone’s likelihood of developing this mental illness. Contributing risk factors include genetics, childhood maltreatment or trauma, and substance misuse, along with stressful life events, other medical conditions, brain differences, and social variables, all play some role. Risk factors are not fate.
Related: What It’s Like Living With a Bipolar Spouse
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