Emotional Instability: Causes and What Helps

What emotional instability looks like

Emotional instability is a pattern, not a single bad day. Signs include:

• moods that shift within hours, often triggered by small events
• emotions that feel overwhelming and out of proportion
• difficulty calming down once upset
• sudden anger, tearfulness or panic
• acting on emotions in ways you later regret, such as outbursts, impulsive decisions or self-harm
• feeling empty or unsure who you are between emotional storms

How long each swing lasts is an important clue. Shifts over minutes to hours suggest emotional dysregulation, as in borderline personality disorder or ADHD. Distinct episodes lasting days to weeks suggest a mood disorder such as bipolar disorder.

Common causes

Borderline personality disorder

Borderline personality disorder (BPD) is one of the personality disorders and was formerly called emotionally unstable personality disorder. Emotional instability is its core feature. Other features include intense fear of rejection, unstable relationships, an unstable sense of self, impulsive behavior, chronic emptiness, intense anger, self-harm and brief stress-related paranoia. It usually begins in adolescence or early adulthood and responds well to specialized therapy.

Hormonal changes

Mood swings are common around puberty, before periods, in pregnancy, after birth and during perimenopause. PMDD is a severe form of premenstrual syndrome that causes marked anger, sadness or anxiety in the luteal phase of the cycle.

Medical and physical causes

• Traumatic brain injury, stroke, multiple sclerosis and dementia: can cause irritability or pseudobulbar affect, sudden uncontrollable laughing or crying that does not match how the person feels.
• Thyroid disease: an overactive thyroid causes anxiety and irritability; an underactive thyroid causes low mood.
• Alcohol and drugs: intoxication, withdrawal and long-term use, including cannabis and stimulants.
• Medicines: steroids, some acne treatments, hormonal contraception in some people, and stopping antidepressants abruptly.
• Low blood sugar: irritability when hungry, more marked in diabetes.
• Chronic pain and sleep disorders.

How it is assessed

A primary care doctor, psychiatrist or psychologist will ask about the pattern and duration of mood changes, triggers, sleep, relationships, substance use, trauma, menstrual timing, family history and any thoughts of self-harm. Keeping a mood diary for 2 to 3 months is particularly useful, especially to identify PMDD or bipolar patterns.

Blood tests may check thyroid function, blood count and other causes. A neurological exam or brain scan is considered if mood changes are new, sudden or come with other neurological symptoms.

Treatment

Psychological therapies

• Dialectical behavior therapy (DBT): teaches skills in emotion regulation, distress tolerance, mindfulness and relationships. It is the best-studied treatment for BPD and reduces self-harm.
• Mentalization-based therapy: another effective approach for BPD.
• Cognitive behavioral therapy (CBT): helps with depression, anxiety and anger.
• Family and couples work: for patterns affecting relationships.

Treating underlying conditions

• antidepressants for depression, anxiety and PMDD
• mood stabilizers for bipolar disorder
• ADHD medicine, which often improves emotional control in ADHD
• treating thyroid problems, sleep disorders and substance use

There is no specific medicine for BPD, but medicines may help with related symptoms.

Self-help that makes a difference

• Regular sleep and wake times: sleep loss strongly increases emotional reactivity.
• Reduce or stop alcohol and recreational drugs.
• Regular exercise, which helps mood and stress.
• Learn to name emotions and pause before acting: for example, cold water on the face or paced breathing can reduce intense arousal quickly.
• Plan ahead for known triggers, including the premenstrual phase.

Frequently asked questions

What causes emotional instability?

Common causes include stress, poor sleep, depression, anxiety, ADHD, premenstrual dysphoric disorder, bipolar disorder and borderline personality disorder. Brain injury, dementia, thyroid problems, alcohol, drugs and some medicines can also cause it. A doctor can help work out which applies.

Is emotional instability a mental illness?

Not always. It is a symptom, and short periods of it are common under stress. When it is frequent, long-lasting and affects your life, it may be part of a condition such as borderline personality disorder, bipolar disorder, ADHD or depression, all of which can be treated.

What is the difference between emotional instability and bipolar disorder?

Emotional instability usually involves rapid shifts over minutes or hours in response to events. Bipolar disorder causes distinct episodes of high or low mood that last days to weeks, with changes in sleep, energy and activity, and can occur without obvious triggers.

Can emotional instability be treated?

Yes. Dialectical behavior therapy and other talking therapies teach practical skills to manage intense emotions. Treating underlying depression, ADHD, PMDD or bipolar disorder also helps. Many people with borderline personality disorder improve substantially over time.