What bipolar disorder is
Bipolar disorder is a mood disorder with episodes of depression and episodes of mania (bipolar I) or hypomania, a milder form (bipolar II). During mania, a person may feel very happy, energetic or irritable, need little sleep, talk quickly, have racing thoughts, make impulsive decisions and, in severe cases, lose touch with reality.
Episodes last days to weeks or longer, and between episodes many people have periods of stable mood.
What borderline personality disorder is
- Intense emotions that change quickly, often within hours.
- Strong fear of abandonment and efforts to avoid it.
- Unstable, intense relationships that swing between idealising and devaluing others.
- An unstable sense of identity.
- Impulsive behaviours, such as spending, substance use or risky sex.
- Self-harm or suicidal behaviour.
- Chronic feelings of emptiness and intense anger.
BPD is also called emotionally unstable personality disorder (EUPD). See fear of abandonment.
Key differences
- Duration of mood changes: bipolar episodes last days to weeks; BPD mood shifts typically last hours.
- Triggers: bipolar episodes can occur without obvious triggers; BPD emotions are often triggered by interpersonal events.
- Pattern: bipolar disorder is episodic; BPD is a more constant pattern of instability.
- Sleep: reduced need for sleep without tiredness is typical of mania, not BPD.
- Sense of self and relationships: central difficulties in BPD.
- Treatment: medication is central in bipolar disorder; specialist therapy is central in BPD.
Why they are confused
Both involve intense emotions, impulsivity, depression and risk of self-harm. Rapid-cycling bipolar disorder, with four or more episodes a year, can resemble BPD. Some people have both conditions. Misdiagnosis can lead to treatments that do not help, so a careful history of mood patterns over time is essential.
Causes and risk factors
- Bipolar disorder: strong genetic component; triggers can include stress, sleep disruption and substance use.
- BPD: combination of temperament, genetics and environment, often including childhood trauma, neglect or invalidating environments.
- Both can be worsened by substance misuse and stress.
How they are diagnosed
A psychiatrist or psychologist makes the diagnosis through a detailed interview about current and past symptoms, the duration and triggers of mood changes, relationships, family history and functioning. Mood diaries and information from family members can help. There are no blood tests or scans for either condition.
Treatment of bipolar disorder
- Mood stabilisers such as lithium, and some anticonvulsant or antipsychotic medicines.
- Psychological therapy, including psychoeducation and CBT.
- Regular routines, sleep and recognising early warning signs.
- Support for family and carers.
Treatment of BPD
- Dialectical behaviour therapy (DBT): skills for emotional regulation, distress tolerance and relationships.
- Mentalisation-based therapy (MBT).
- Schema therapy and other structured approaches.
- Medication is not the main treatment but may help coexisting conditions.
Many people with BPD improve significantly over time with treatment.
Living with either condition
- Regular sleep, exercise and routines.
- Avoiding alcohol and drugs.
- Building a support network.
- Creating a crisis plan with professionals.
- Learning about the condition with family and friends; see how to help someone with depression.
Reducing stigma
Both conditions are often misunderstood. People with bipolar disorder or BPD are not “dramatic” or “manipulative”; they are experiencing real, often painful symptoms. With the right diagnosis and treatment, many people live fulfilling lives, maintain relationships and work.
Two examples
- Bipolar disorder: for ten days, a person sleeps three hours a night without feeling tired, starts several big projects, spends heavily and talks rapidly; weeks later, they fall into a deep depression lasting a month.
- BPD: after a friend cancels plans, a person feels intense rejection and anger within minutes, sends many messages, then feels empty and ashamed; by evening, the mood has shifted again.
When to seek urgent help
- Thoughts of suicide or self-harm: contact emergency services or a crisis line.
- Severe mania with risky behaviour, no sleep for days or losing touch with reality.
- Severe depression with inability to care for yourself.
- Feeling unsafe or overwhelmed.
Key points to remember
- Bipolar disorder involves mood episodes lasting days to weeks.
- BPD involves rapid, reactive emotional shifts and relationship difficulties.
- They can overlap and coexist; careful diagnosis matters.
- Bipolar is mainly treated with medication and therapy; BPD with specialist therapy.
Questions about bipolar disorder and BPD
These answers are general information and do not replace an examination or individual medical advice.
Is BPD a type of bipolar disorder?
No. BPD is a personality disorder; bipolar disorder is a mood disorder.
What is the main difference between bipolar and BPD?
Bipolar mood episodes last days to weeks; BPD mood shifts usually last hours and are triggered by events.
Can you have both bipolar and BPD?
Yes. Some people have both.
Is manic depression the same as bipolar disorder?
Yes. Manic depression is an older name for bipolar disorder.
Can BPD be cured?
Many people improve significantly with therapy and no longer meet the criteria over time.
Does medication help BPD?
It is not the main treatment, but it can help coexisting symptoms.
How do I know which one I have?
Only a mental health professional can make an accurate diagnosis.
Sources
- NHS · Bipolar disorder
- NHS · Borderline personality disorder
- NIMH · Bipolar disorder
- NIMH · Borderline personality disorder
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.