Mood swings refer to sudden and intense fluctuations in emotional states that can range from feelings of euphoria and irritability to sadness and anxiety.

While occasional mood changes are a natural part of human experience, frequent or severe mood swings can signal underlying medical, psychological, or environmental issues.

Hormonal Influences on Mood Swings

Hormones play a pivotal role in regulating mood states by influencing brain chemistry and physiological responses. Several hormonal changes throughout life are notably linked to mood fluctuations:

Puberty: The surge in hormones such as estrogen and testosterone during adolescence creates emotional instability and can intensify mood swings.

Pregnancy and Postpartum: Hormonal shifts before and after childbirth may induce mood swings and contribute to postpartum depression.

Menopause: Declining hormone levels, particularly estrogen, in menopause often lead to mood instability, irritability, and depressive symptoms.

Psychological and Psychiatric Causes

Several mental health conditions are fundamentally associated with significant mood swings:

Bipolar Disorder: Characterized by alternating episodes of mania or hypomania and depression, this condition exemplifies extreme mood variability and requires medical intervention.

Borderline Personality Disorder (BPD): Rapid and intense mood swings triggered by interpersonal stressors and emotional dysregulation are hallmark features.

Depression and Anxiety Disorders: These disorders commonly involve erratic mood changes, including irritability and heightened emotional reactivity.

Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorders: Individuals with these neurodevelopmental conditions often display mood instability linked to sensory sensitivities or frustration tolerance.

Neurological and Medical Conditions

Underlying physical illnesses and neurological disorders can significantly affect mood regulation:

Thyroid Dysfunction: Both hyperthyroidism and hypothyroidism alter energy levels and brain function, leading to irritability, depression, or anxiety.

Chronic Illness:Chronic illnesses and autoimmune conditions may also contribute to sustained emotional distress. The burden of long‑term disease, inflammation, and treatment demands can impair mood regulation, weaken resilience, and increase vulnerability to depression or anxiety.

Central Nervous System Disorders: For example, Multiple Sclerosis (MS), neurodegenerative diseases, or other neurological conditions — frequently involve changes to brain circuits that regulate mood, cognition, and behaviour. Patients with such disorders often experience elevated rates of depression, mood instability, emotional blunting or mood lability, and other psychiatric or cognitive symptoms.

Biochemical and Neurochemical Factors

Mood regulation depends on balanced neurotransmitter activity in the brain. Imbalances or disruptions in serotonin, dopamine, norepinephrine, and gamma-aminobutyric acid (GABA) pathways can precipitate erratic mood states. For example, serotonin deficits are linked to depression and irritability, while dopamine dysregulation may influence mood elevation or agitation.

Lifestyle and Environmental Triggers

Non-medical factors also contribute to mood swings:

Sleep Deprivation: Lack of restorative sleep impairs emotional control and heightens mood reactivity.

Stress: Psychological stress from work, relationships, or trauma can destabilize mood.

Dietary Factors: Fluctuations in blood sugar due to irregular eating or excessive sugar intake provoke mood changes.

Substance Withdrawal or Use: Cessation from or use of caffeine, nicotine, or drugs impacts mood stability.

According to Dr. Nassir Ghaemi, mood disorders should be understood as emerging from complex interactions among biological, psychological, and environmental factors. He argues that effective treatment depends on carefully identifying the root causes rather than relying solely on symptomatic classification.

Mood swings arise from an intricate interplay of hormonal shifts, psychiatric conditions, medical illnesses, neurochemical imbalances, and lifestyle factors. Medical and neurological diseases impact brain function, contributing to erratic moods.