What Is Bipolar Disorder?
Bipolar disorder (formerly known as manic-depressive illness) is a chronic mental health condition characterised by significant fluctuations in mood, energy, activity levels, and the ability to carry out day-to-day tasks. These fluctuations go far beyond the ordinary ups and downs that most people experience — they are extreme, often unpredictable, and can have profound effects on a person's life, relationships, and functioning.
The condition is defined by the presence of mood episodes — discrete periods of abnormal mood that differ markedly from the person's usual state. These episodes fall into two broad categories: elevated mood states (mania and hypomania) and depressed mood states (depressive episodes).
Between episodes, many people with bipolar disorder function well, though some experience residual symptoms or ongoing difficulties with mood regulation.
Types of Bipolar Disorder
Bipolar I Disorder
Bipolar I is defined by the occurrence of at least one manic episode. Manic episodes may be preceded or followed by hypomanic or major depressive episodes, but these are not required for the diagnosis. Manic episodes in Bipolar I are severe enough to cause marked impairment in social or occupational functioning, may require hospitalisation, and may include psychotic features.
Bipolar II Disorder
Bipolar II is characterised by a pattern of hypomanic episodes and major depressive episodes, but no full manic episodes. Hypomania is a less severe form of mania that does not cause the same level of functional impairment. Bipolar II is often misdiagnosed as unipolar depression because the hypomanic episodes may not be recognised as problematic — or may even feel positive — while the depressive episodes are the primary source of distress.
Cyclothymic Disorder (Cyclothymia)
Cyclothymia involves numerous periods of hypomanic symptoms and depressive symptoms over at least two years (one year in children and adolescents) that do not meet the full criteria for hypomanic or major depressive episodes. It represents a milder but chronic form of mood instability.
Other Specified and Unspecified Bipolar Disorders
These categories cover presentations that do not fit neatly into the above categories but involve clinically significant bipolar-spectrum features.
Symptoms of Bipolar Disorder
Manic Episode Symptoms
A manic episode involves a distinct period of abnormally elevated, expansive, or irritable mood and increased goal-directed activity or energy, lasting at least one week. During this period, three or more of the following are present:
- Inflated self-esteem or grandiosity
- Decreased need for sleep (feeling rested after only a few hours)
- More talkative than usual or pressure to keep talking
- Racing thoughts or flight of ideas
- Distractibility
- Increased goal-directed activity or psychomotor agitation
- Excessive involvement in activities that have a high potential for painful consequences (reckless spending, sexual indiscretions, unwise business investments)
Hypomanic Episode Symptoms
Hypomanic episodes involve the same symptom profile as manic episodes but are less severe, last at least four consecutive days, and do not cause the marked impairment or require hospitalisation. The mood change is observable by others but the person may function reasonably well.
Depressive Episode Symptoms
Depressive episodes in bipolar disorder are clinically indistinguishable from major depressive episodes and involve persistent low mood, loss of interest, fatigue, sleep and appetite changes, cognitive difficulties, feelings of worthlessness, and potentially suicidal ideation. Depressive episodes are typically longer in duration than manic or hypomanic episodes and are often the primary source of disability in bipolar disorder.
Causes and Risk Factors
Genetic Factors
Bipolar disorder has one of the strongest genetic components of any psychiatric condition. Twin studies suggest heritability of approximately 70–80%. Having a first-degree relative with bipolar disorder increases risk substantially, though many people with a family history never develop the condition.
Neurobiological Factors
Research has identified abnormalities in brain structure and function in bipolar disorder, particularly in regions involved in emotional regulation, including the prefrontal cortex, amygdala, and hippocampus. Dysregulation of circadian rhythms — the body's internal clock — is thought to play an important role, which explains why sleep disruption is both a trigger for and a symptom of mood episodes.
Environmental Triggers
While genetic factors create vulnerability, environmental factors often trigger the onset of episodes. Common triggers include sleep disruption, significant life stressors (positive or negative), substance use, and major life transitions. Identifying and managing personal triggers is an important aspect of living with bipolar disorder.
Bipolar Disorder and Suicide Risk
Bipolar disorder is associated with significantly elevated suicide risk. Studies suggest that 25–50% of people with bipolar disorder attempt suicide at least once, and the condition accounts for a disproportionate share of suicide deaths. Risk is highest during depressive episodes and mixed states (when depressive and manic symptoms occur simultaneously). Recognising warning signs and having a safety plan are important aspects of managing the condition.
When to Seek Professional Help
Seek professional assessment if:
- You experience episodes of unusually elevated mood, energy, or decreased need for sleep
- You have periods of depression alternating with periods of elevated or irritable mood
- Mood changes are severe enough to affect your work, relationships, or safety
- You are having thoughts of self-harm or suicide
- You have a family history of bipolar disorder and are experiencing mood instability
Accurate diagnosis of bipolar disorder requires a thorough clinical assessment. A GP can provide an initial assessment and refer you to a psychiatrist for specialist evaluation. Under the National Health Act (Section 6), you have the right to be informed about your condition and to participate in decisions about your care.