Researchers and mental health experts speculate that several risk factors, including genetics and environment, affect someone’s chance of developing bipolar disorder. However, they cannot pinpoint a single cause that leads to its development. While people with bipolar disorder cannot inherently control the development of their symptoms, seeking treatment can provide significant relief and help with living a fulfilling life.
What Causes Bipolar Disorder?
Bipolar disorder can be induced in multiple ways, including substance-induced, medical-related, and unspecified. Bipolar disorder is a mental health condition characterized by episodes of major depression and mania (in the case of bipolar I disorder) or hypomania (in the case of bipolar II disorder). Although people often associate bipolar disorder with ongoing mood swings, many people with this condition do not experience such rapid cycling.1
The average onset for bipolar disorder is around age 25, and although teenagers often exhibit some initial symptoms, 90% of people experience onset before 50.2
Genetic Causes of Bipolar Disorder
Research suggests that genetics and bipolar disorder are closely linked, with some studies suggesting that heritability accounts for 60-80% of all cases.3 People with bipolar disorder are significantly more likely to have a first-degree relative who also has the condition. However, if a family member has bipolar disorder, that doesn’t automatically mean someone else will develop it.
Bipolar & Co-Occurring Disorders
There are high levels of comorbidity between bipolar disorder and other mental health conditions, particularly with panic disorder, obsessive-compulsive disorder, eating disorders, ADHD, and personality disorders. In addition, there is a strong relationship between bipolar disorder and addiction.4
Imbalances in Brain Structure & Chemistry in Bipolar Disorder
Abnormalities in brain chemistry may predispose someone to develop bipolar disorder. Scientists continue to study specific interactions within the glutamatergic system, central nervous system (CNS) energy, and gray matter within the brain. Bipolar disorder medications are considered front-line treatment methods, as these drugs aim to enhance the brain’s neurotransmitter balance.5
Loss of Brain Cells
Although there isn’t much research on the topic, one study found that blood in people with bipolar disorder can be toxic to brain cells. This toxicity impacts neuron connectivity. The more bipolar episodes the individual experiences, the more structural stress the brain undergoes.6
Neurotransmission pathways seem to coincide closely with mental health. Several transmission pathways, including the serotonin, norepinephrine, dopamine, γ-Aminobutyric acid (GABA), and glutamate systems, have been evaluated for their potential roles in bipolar disorder.7
Research has also shown a correlation between mitochondrial dysfunction and mood disorders, including bipolar disorder. Mitochondria provide energy, and they generate power for biochemical reactions. Impairment can result in higher levels of metabolic changes and oxidative damage.8
Childhood Trauma & Bipolar Disorder
While people likely have genetic predispositions for bipolar disorder, environmental factors, including childhood trauma, can profoundly affect how the brain develops. If someone is genetically vulnerable to mental health issues, trauma may exacerbate the initial symptoms.
Research shows that people with bipolar disorder who indicate childhood trauma tend to have more severe clinical presentations over time. They tend to exhibit symptoms earlier, and they are at a heightened risk for substance abuse and suicide attempts. In addition, people with bipolar disorder are more likely to report a history of childhood trauma than control groups.9
Experiences of childhood trauma that can lead to developing bipolar disorder include:
- Sexual/physical/emotional abuse
- Witnessing violence in the home
- Growing up with a relative with a mental illness
- Losing close loved ones
- Surviving a natural disaster
- Financial insecurity or poverty
- Terrorism or war
Environmental & Lifestyle Causes of Bipolar Disorder
Some data show relationships between environment and lifestyle factors and bipolar disorder. For example, climate can affect mood, and mania seems to have peaks in spring and summer, whereas depressive symptoms tend to be more common in the winter. Another study found that maternal smoking and maternal infections may increase the risk of various mental illnesses during fetal neurodevelopment.10
Chronic stress can affect brain functioning and development, especially in young children. Stress can also worsen mental health symptoms and complicate treatment efforts. Research shows that interpersonal stress may trigger more depressive or manic episodes and intensify the longitudinal course of bipolar disorder.11
Experiences of stress that can lead to developing bipolar disorder include:
- Relationship stress
- Financial stress
- Isolation and loneliness
- Work-related anxiety and stress
- Losing someone
- Physical illness
- Life transitions
- Birth of a child
- School-related stress
- Getting married
- Separation or divorce
- Being incarcerated
Alcohol & Substance Use
Substance use and bipolar disorder can be closely connected. Certain drugs, like stimulants, can mimic manic symptoms. Similarly, withdrawal symptoms often look like depressive symptoms. Many people with substance use disorders self-medicate mental health symptoms to temporarily cope with their distress.
While it remains unclear whether certain medications can provoke bipolar disorder or just symptoms of the condition, drug-induced bipolar disorder indicates that certain substances can impact brain chemistry. In some cases, stopping a medication suddenly can trigger manic or depressive episodes while the brain stabilizes. In others, the medication itself can stimulate these reactions.
Medications that can cause drug-induced bipolar disorder or mania symptoms include:
- Benzodiazepines: The sedative properties of benzodiazepines may exaggerate depressive symptoms and can prematurely trigger manic or hypomanic episodes.
- Antidepressants: Medication for depression might increase the likelihood of mania in someone with major depressive disorder.
- Nasal decongestants: Nasal decongestants with ephedrine may induce or exaggerate manic symptoms.
- Opioids: Opioid analgesics, such as hydrocodone, may induce mania, and lifetime exposure to opioids is associated with mood disorders.
People with bipolar disorder tend to have more physical health problems than control groups. They have higher rates of asthma, migraines, and higher cholesterol levels. They’re also more likely to have osteoarthritis, thyroid disease, and hypertension.12
Untreated physical health issues may exacerbate bipolar symptoms.
Other Risk Factors for Developing Bipolar Disorder
Approximately 2.8% of the US adult population reports experiencing bipolar disorder within the past year. About one in every 100 adults will be diagnosed during their lifetime. These numbers tend to be relatively equal among men and women. However, the diagnostic rates of bipolar disorder are higher for adolescent girls than adolescent boys.
Some additional risk factors that can play a role in someone’s chances of developing bipolar disorder include:
- Being young: The median age for bipolar disorder is about 25, and it’s rare for symptoms to emerge after age 40
- Being a woman: Although bipolar disorder statistics are mostly equal, women tend to experience more periods of rapid cycling, and they often have more depressive episodes.
- Having a history of depression as an adolescent: Up to 20% of teens with major depression develop bipolar disorder within five years.
- Having a parent with bipolar disorder: One parent with bipolar disorder increases the child’s risk of developing bipolar disorder by 15-30%. Having two parents increases the risk by 50-75%.13
Triggers That Can Worsen Bipolar Symptoms
There are several common triggers stemming from environmental factors, lifestyle choices or occurrences that can increase bipolar symptoms’ severity. It’s important to be mindful of the various triggers that may worsen bipolar symptoms. Some triggers are obvious, but others may be more subtle. As you become more aware of your condition, you will likely cultivate greater insight into your specific triggers.
Triggers that can cause increased symptoms of bipolar disorder include:
- Stressful life events: Both acute and chronic stress can negatively impact your mental health.
- Overstimulation: Sensory overload can induce mania.
- Substance use: Substance use can induce either manic or depressive symptoms, and it may also temporarily mask symptoms (although it doesn’t make them go away).
- Untreated physical illness: Untreated physical illness can go hand-in-hand with depression.
- Poor sleep: Issues with sleep and sleep deprivation are common triggers for manic episodes.
- Changes in routine: Changes in routine or a general lack of structure can affect mood and be associated with adjustment disorders.10
When to Seek Professional Help
A qualified medical doctor, psychiatrist, or mental health professional can diagnose bipolar disorder. Once you’re properly diagnosed, you will be given a treatment plan with goals and objectives relative to your care.
Although there isn’t a cure for bipolar disorder, many bipolar disorder treatments can help you live a meaningful and enjoyable life. Improvement in symptoms will depend on adherence to your treatment. Most people benefit from a combination of therapy, medication, and lifestyle changes. You can find a therapist specializing in bipolar and related disorders using an online therapist directory, and medication services are easily accessible through online psychiatry options.
There isn’t a single cause for bipolar disorder. However, a combination of risk factors plays a role in developing mental illnesses, such as bipolar disorder. If you suspect you or a loved one is experiencing depressive, manic, or hypomanic symptoms, it’s important to seek support.