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Bipolar disorder
This condition involves episodes of both elevated mood (mania or hypomania) and depression, which can significantly impact daily life. It typically emerges in late adolescence or early adulthood, affecting approximately 1% of the population.
Overview
Bipolar disorder is a long-term mental health condition that causes significant changes in a person's mood, energy, and activity levels. These changes go beyond typical mood swings and can range from periods of extreme high mood and energy, known as mania or hypomania, to periods of deep low mood and lack of energy, known as depression [PMID:33678794]. The precise causes of bipolar disorder are not fully understood, but it is believed to result from a combination of genetic, biological, and environmental factors.
Living with bipolar disorder can be challenging, as the unpredictable nature of mood episodes can affect personal relationships, work, and overall quality of life. However, with appropriate care and management strategies, individuals can learn to manage their symptoms effectively and lead fulfilling lives. Early diagnosis and intervention are important for improving long-term outcomes.
Symptoms & clinical features
The symptoms of bipolar disorder fluctuate, presenting as distinct episodes of mania (or hypomania) and depression. During a manic episode, individuals may experience an elevated or irritable mood, increased energy, reduced need for sleep, rapid speech, racing thoughts, and engaging in risky behaviours [PMID:33678794]. Hypomania is a milder form of mania with similar symptoms, but they are less severe and do not typically lead to significant disruption in daily life or require hospitalisation.
Depressive episodes in bipolar disorder share many features with major depression. Symptoms can include persistent sadness, loss of interest in activities, fatigue, changes in appetite or sleep patterns, feelings of worthlessness or guilt, and difficulty concentrating [PMID:33678794]. These episodes can be debilitating, profoundly affecting a person's ability to function. The pattern and severity of these mood shifts vary considerably between individuals.
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Affected organs
Bipolar disorder is primarily a condition affecting the brain and mental health. It does not directly affect specific organs in the same way a physical illness might damage the heart or kidneys. Instead, it impacts brain function, affecting the neural circuits responsible for mood regulation, executive function, and impulse control. While the disorder itself is brain-based, its chronic nature and associated lifestyle factors can indirectly influence physical health over time.
Risks & severity
Bipolar disorder typically presents in late adolescence or early adulthood, although it can manifest at any age [PMID:33678794]. The severity of the condition varies widely; some individuals experience infrequent episodes, while others have rapid cycling, meaning they experience four or more mood episodes within a year. Prognosis is very individual and depends on factors such as adherence to treatment, lifestyle choices, and co-occurring conditions.
The lifetime risk for bipolar disorder is estimated to be around 1% of the general population. Factors that may increase the risk of developing bipolar disorder include having a first-degree relative with the condition, experiencing significant stress, or trauma. There is no cure for bipolar disorder, but it is a manageable condition, and many people live stable lives with effective treatment plans.
Genetic causes
Bipolar disorder is considered a complex or polygenic condition, meaning it is influenced by multiple genes acting together, alongside environmental factors. Research suggests that several genes contribute to an individual's susceptibility. For example, variations in genes such as ANK3 (ankyrin 3), CACNA1C (calcium voltage-gated channel subunit alpha1 C), and ODZ4 (teneurin transmembrane protein 4) have been associated with an increased risk of bipolar disorder [PMID:33678794].
These genes play roles in brain development and function. ANK3 is involved in the function of ion channels in neurons, which are crucial for electrical signalling in the brain. CACNA1C codes for a subunit of a voltage-gated calcium channel, also important for neuronal communication and plasticity. ODZ4 is involved in neuronal connectivity and synapse formation. Changes in these genes may alter brain circuitry and neurochemical balance, contributing to the development of mood dysregulation seen in bipolar disorder.
Inheritance pattern
Bipolar disorder has a complex inheritance pattern, which means it is not inherited in a simple dominant or recessive manner. Instead, it is considered a polygenic or multifactorial condition. This means that multiple genetic variations, each with a small effect, combine to increase a person's susceptibility to the condition. These genetic factors interact with environmental influences to determine whether an individual develops bipolar disorder.
If one parent has bipolar disorder, the risk for their children is increased compared to the general population, though most children will not develop the condition. inheriting a predisposed genetic profile does not guarantee that someone will develop bipolar disorder; rather, it increases their vulnerability. Family members who wish to understand their personal risk can benefit from speaking with a genetic counsellor.
Diagnosis & testing
Diagnosing bipolar disorder typically involves a comprehensive evaluation by a mental health professional, such as a psychiatrist. This usually includes a detailed clinical interview, assessment of symptoms, medical history, and may involve input from family members or close contacts [PMID:33678794]. There are no specific laboratory tests or brain scans that can definitively diagnose bipolar disorder. Diagnosis relies on clinically recognised criteria outlined in diagnostic manuals.
In the UK, if bipolar disorder is suspected, a general practitioner (GP) will typically make a referral to NHS mental health services for a specialist assessment. Genetic testing for bipolar disorder is currently not part of routine clinical diagnosis within the NHS, as the condition is polygenic and environmental factors play a significant role. The clinical diagnosis focuses on symptom presentation and course of illness.
Management & lifestyle
Management of bipolar disorder typically involves a combination of medication, psychological therapies, and lifestyle adjustments. Mood stabilisers, such as lithium, and certain anti-epileptic drugs, are often prescribed to help prevent mood swings [PMID:33678794]. Antipsychotics and antidepressants may also be used, depending on the specific symptoms and phase of the illness. Psychological therapies, like cognitive behavioural therapy (CBT) and psychoeducation, can help individuals understand their condition, develop coping strategies, and manage stress.
Living with bipolar disorder can also benefit from developing a consistent routine, managing stress, ensuring adequate sleep, maintaining a healthy diet, and avoiding substances like alcohol and recreational drugs. Regular monitoring by a mental health team is crucial to adjust treatments and provide ongoing support. Individuals should discuss all their treatment options and concerns with their healthcare professionals.
UK care pathway
In the UK, individuals suspected of having bipolar disorder will typically be referred by their GP to specialist NHS mental health services. These services are accessed via local trusts and can include assessment and ongoing care from psychiatrists, specialist nurses, and other mental health professionals. While there isn't a specific NHS R-code for genetic testing for common, polygenic mental health conditions like bipolar disorder, clinical genetic services may be accessed for families with unusual presentation or a very strong family history, particularly if there are other rare genetic conditions present.
Genetic counsellors are available within NHS clinical genetics departments to discuss inheritance patterns, recurrence risks, and address any concerns family members may have about genetic predisposition. They can help navigate complex genetic information in a sensitive and understandable way.
Frequently asked questions
What is the difference between bipolar I and bipolar II disorder?
Bipolar I disorder involves at least one manic episode, which may or may not be followed by a depressive episode. Bipolar II disorder involves at least one hypomanic episode and at least one major depressive episode, but never a full manic episode.
Can bipolar disorder be cured?
There is currently no cure for bipolar disorder, as it is a chronic, lifelong condition. However, it is highly manageable with a combination of medication, therapy, and lifestyle adjustments. Many people with bipolar disorder can lead stable and fulfilling lives.
Is bipolar disorder always inherited?
Bipolar disorder does have a strong genetic component, meaning it can run in families. However, it's a complex condition influenced by multiple genes and environmental factors, so inheriting a genetic predisposition does not guarantee someone will develop it.
What should I do if I think someone I know has bipolar disorder?
If you are concerned about someone, encourage them to speak to their GP or another healthcare professional. They can provide an initial assessment and refer to specialist mental health services if needed. Support and understanding are very helpful.
Are there different types of medication for bipolar disorder?
Yes, common medications include mood stabilisers like lithium, and certain antipsychotics. Sometimes antidepressants are also used, typically with a mood stabiliser. The choice of medication depends on the individual's specific symptoms and the phase of their illness.
References
- Lane NM, Smith DJ. Bipolar disorder: Diagnosis, treatment and future directions. The journal of the Royal College of Physicians of Edinburgh. 2023. PMID: 37649414
- Malhi GS, Jadidi M, Bell E. The diagnosis of bipolar disorder in children and adolescents: Past, present and future. Bipolar disorders. 2023. PMID: 37433682
- Carvalho AF, Firth J, Vieta E. Bipolar Disorder. The New England journal of medicine. 2020. PMID: 32609982
- Dilsaver SC. Bipolar disorder. American family physician. 1989. PMID: 2672748
- Miller TH. Bipolar Disorder. Primary care. 2016. PMID: 27262007
- Strejilevich SA, Quiroz D, Bitran JA. Bipolar Disorder. The New England journal of medicine. 2020. PMID: 32997928
- Shakespeare J, Dixon S, Marwaha S. Primary care and bipolar disorder. The British journal of general practice : the journal of the Royal College of General Practitioners. 2023. PMID: 36823056
- Anderson IM, Haddad PM, Scott J. Bipolar disorder. BMJ (Clinical research ed.). 2012. PMID: 23271744