A person may recognize something that has triggered a shift in their mood, such as a stressful event at work. But it’s also not uncommon for mood swings to occur without an obvious cause. People may even experience changes in mood if they have an underlying mental health issue.

Common Causes of Mood Swings

Everyone experiences mood swings from time to time, but if you seem to get them frequently or they are so intense that they disrupt your daily life, including work and relationships, it may be a sign of an underlying condition that needs treatment. Internal changes that take place throughout our lives influence our mood, but it’s not just what’s happening inside that determines how we feel; we also respond to what’s happening around us. External changes to our lives and in our environments, such as increased stress at home, school, or work, also can influence our emotions.

Illness and Injury

Even though the term “mood swings” implies an emotional root, the shifts also can be associated with chronic diseases or acute injuries that affect the brain, such as dementia, concussion, or a stroke. Other medical conditions, particularly neurological conditions, also can cause mood swings, including:

DiabetesMultiple sclerosisParkinson’s diseaseSleep disordersThyroid disorders

Developmental Stages

Toddlers and young children often appear “moody” and may throw tantrums as they learn to regulate their emotions. While these changes are generally a normal part of emotional development, mood swings in children also can be a sign of an underlying mental health disorder, learning disability, or even a physical ailment. As kids get older, mood swings continue to be a normal part of their development. By the time they enter the preteen years, fluctuations in mood are primarily driven by hormonal changes. These shifts in mood tend to peak during adolescence and gradually stabilize by young adulthood. 

Allergies

If you have seasonal allergies, you may find that your mood is influenced by the time of year you tend to have symptoms. Constant sneezing, watery eyes, post-nasal drip, and itchiness also can lead to fatigue, especially if your allergies interfere with sleep.

Medications

Starting or stopping a prescription medication can affect a person’s mood. While medications such as antidepressants and mood stabilizers are expected to affect a person’s moods, medications prescribed for other reasons also may cause mood swings as a side effect. Even though mood changes can be a symptom of depression or another mental health condition, some medications used to treat these disorders can cause changes in mood. Sometimes, these mood shifts indicate that the medication isn’t the right choice for treatment, or that the diagnosis someone has been given may not be correct.  For example, a person who has bipolar disorder may be misdiagnosed with depression and prescribed medication. But, certain antidepressants may trigger a manic episode in someone with bipolar disorder. Likewise, people who take anabolic steroids can experience intense mood changes, including rage.

Hormones

Other possible causes of mood swings may stem from changes in hormone levels, particularly estrogen. Fluctuations in hormones are normal and are well known to impact mood, such as the periodic changes of the menstrual cycle. For the same reason, mood swings are also common in response to other causes of shifting levels of hormones, such as pregnancy and menopause. Certain forms of hormonal birth control, such as the Pill, may help ease mood swings associated with the menstrual cycle, but it also has been suggested that changes in mood could be a side effect of these medications. However, more research is needed, as other studies did not find a link between oral contraceptives and mood swings. 

Mood Swings and Mental Illness

While shifts in mood can be completely normal, triggered by stress, and/or part of dealing with a physical health condition, mood swings also can be a symptom of mental illness.  When characterizing and diagnosing mental health disorders, particularly bipolar disorder and borderline personality disorder, the constellation of intense, rapid, and frequent shifts in mood is sometimes referred to as “emotional lability.”  However, a labile mood is not unique to mental illness. It’s also seen in people with traumatic brain injury, stroke, and Alzheimer’s, as well as other medical conditions. 

Depression

Mood swings are also common with depression, especially if it is untreated. A person’s mood may fluctuate from irritability to extreme sadness to an angry outburst. People who are depressed also may have other symptoms, such as:

Feeling sad, hopeless, and worthless Failing to enjoy favorite activities Having trouble sleeping or sleeping too much Eating more than usual or not eating enough Feeling exhausted, tired, and fatigued Having difficulty concentrating and/or making decisions Experiencing thoughts of death or suicide

Bipolar Disorder

Mood swings are a hallmark symptom of bipolar disorder. There are two main types of bipolar disorder: bipolar I and bipolar II. Both are characterized by periods of mania or hypomania that alternate with depression. Some people experience both sets of symptoms at the same time, which is known as mixed episodes.  The mood swings for people with bipolar disorder may contain some or all of the symptoms of a depressive or manic/hypomanic episode. A person experiencing an episode of mania may:

Talk a lot or very fastHave excess energy Engage in risky behaviorAppear “on edge” or irritableFeel like sleeping less than they normally do and don’t feel tiredBe more active or goal-oriented than usual (e.g., taking on new projects, working more or harder, and starting new hobbies)

During a period of depression, a person with bipolar disorder may: 

Feel worthless or hopelessStop feeling like doing things they used to enjoySeem sad, cry often, or be tearfulHave no energy, feel exhausted, or are “wiped out”Feel like they can’t focus or concentrate or thoughts/tasksSleep more than usual or be unable to fall/stay asleepEat more or less than they usually do (weight loss or gain)Have thoughts of dying or death; planning/attempting suicide

How long it takes for the episodes to change a person’s mood to the other end of the spectrum can vary from person to person. People who have “rapid-cycling” symptoms may experience shifts daily or weekly, while others may stay in one type of episode for months or years. For more mental health resources, see our National Helpline Database. Medications used to treat bipolar disorder may help manage these intense shifts. Of note, researchers are getting better at predicting the mood shifts in people with bipolar disorder, which may help doctors diagnose and treat the condition. 

Borderline Personality Disorder

Borderline personality disorder (BPD) is another mental health disorder that can cause persistent mood swings. These mood shifts are typically intense and variable and can last from a few hours to a few days. Other symptoms of BPD include:

Impulsive and risky behavior such as unprotected sex, reckless driving, and substance use Extreme reactions, such as rage or panic, to abandonment (real or imagined) Feeling empty or restless Self-harming, threatening, or attempting suicide Emotional and intense relationships with others Anger issues such as outbursts, inappropriate anger, and an inability to control temper Dissociative symptoms such as a loss of time or feeling “outside” one’s own body

Lifestyle Risk Factors for Mood Swings

When it comes to risk factors for mood swings, a number of factors may come into play. However, the biggest contributors to mood swings include diet, sleep, and substance abuse. Here’s a closer look at how these risk factors can increase the likelihood of mood swings.

Diet

A person who is eating a diet that’s nutritionally inadequate or not getting enough to eat may experience mood changes in response to fluctuating blood sugar levels and malnourishment. For example, if you notice your grouchy coworker has more spring in their step after they have breakfast and a cup of coffee, their bad morning mood may have been stemming from caffeine withdrawal or low blood sugar known as hypoglycemia.  Digestive disorders that affect the body’s ability to absorb nutrients, such as celiac disease and inflammatory bowel disease (IBD), have also been associated with mood swings. These conditions also have been linked to specific mental health conditions, such as depression.

Sleep

A person’s mood also can be heavily influenced by the amount and quality of sleep they get. A person who is sleep-deprived, especially when chronic, may experience intense mood fluctuations, as well as other psychiatric symptoms. Maybe your colleague just isn’t much of a morning person, but their mood naturally lifts as they wake up and they feel more prepared for the day ahead. The body’s circadian rhythm, which is known for influencing when we sleep, also drives our mood throughout the day to a certain extent. 

Substance Abuse

People who are dealing with substance use disorders also may be more prone to experiencing extreme shifts in mood, especially when they are unable to get or use a substance. They also may experience mood swings when they are trying to quit a drug and experiencing withdrawal. When misused, medications known to cause mood changes can have especially severe effects. For example, symptoms may be erratic and even life-threatening if a person, such as an athlete, misuses steroid medications. 

Coping With Mood Swings

Mood swings can be challenging to deal with, especially if they interfere with your day-to-day life, school or work, and your relationships. Changes in mood that are frequent and intense should be discussed with your doctor, as you will need to figure out the underlying medical and/or mental health cause before you can effectively treat them. You may be able to manage less frequent, mild, or occasional mood swings on your own, especially if you have a good sense of what triggers them. The first step is identifying factors in your life and environment, such as stress, poor sleep, or skipping your morning coffee, that precede or cause your mood swings.  To better manage and cope with these changes in mood, you may want to experiment with different approaches, such as:

Getting regular exercise Making changes to your diet Learning stress management techniques Adjusting your nightly routine to improve sleep Addressing any substance use issues in your life

A Word From Verywell

While some degree of variation in mood is normal part of life, changes in mood shouldn’t interfere with the quality of your life. If your mood swings don’t improve or get worse, be sure to let your doctor know. Together, you can identify what may be causing your fluctuations in mood.