13 Mood Changes That Could Signal Something Serious

Irritability, mood swings, and depression can all be signs of significant health issues.

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When we think of serious illnesses and medical conditions, we often assume that the earliest and most pronounced symptoms will be physical in nature. And although we should never ignore physical changes in our bodies, it's equally important to take emotional changes seriously. Though it's easy to dismiss symptoms like nervousness and irritability as the response to a bad day at work or an argument with a friend, mood swings and mood changes can be hallmark signs of illnesses, including Parkinson's, diabetes, and heart disease. Here are some mood changes that could be symptoms of something more serious.

1
Short Temper: Hypothyroidism

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If you notice that you've become uncharacteristically short-tempered lately, it could be a sign of hypothyroidism, or an underactive thyroid gland. According to the British Thyroid Foundation, rapid changes in thyroid hormone levels can cause both irritability and snappiness.

Hormone changes aren't the only reason why people with hypothyroidism can be short-tempered. Stephen B. Hill, DC, who frequently treats thyroid disorders at Hill Functional Medicine in Arizona, explains that other symptoms of hypothyroidism include unexplained weight gain, sleep problems, hair thinning, and sweating. "All of these symptoms are likely to make even the happiest of people moody, anxious, or even depressed," he explains. "Nobody feels good on the outside if they are in pain and don't feel well on the inside."

2
Nervousness: Hyperthyroidism

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Thyroid hormones like triiodothyronine (T3) and thyroxine (T4) stimulate the nervous system. Therefore, when you have an overactive thyroid, the nervous system becomes overwhelmed, Baltimore-based endocrinologist Marie Bellantoni, MD, notes. "That's why many people with hyperthyroidism feel nervous, jittery, and anxious, sometimes with problems focusing and a pounding heart," she explains. "It's like having your 'fight or flight' system turned on all the time."

Though anxiety, stress, and consuming too much caffeine can result in similar symptoms that aren't related to your thyroid, Bellantoni says it's better to be safe than sorry. "Fortunately the blood tests for thyroid disease are very sensitive and accurate, and we can use those to tell who has hyperthyroidism," she notes.

3
Euphoria: Multiple Sclerosis

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According to The National Multiple Sclerosis Society, mood changes are a symptom of multiple sclerosis (MS). And though sadness, fear, anxiety, and depression are the most common emotional symptoms of the illness, euphoria can also occur.

The National Multiple Sclerosis Society explains that this surprising expression of happiness is the result of cognitive impairment caused by the disease. Patients who experience euphoria are unrealistically happy and appear unconcerned about problems.

4
Irritability: Diabetes

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Irritability is one of the presenting symptoms of diabetes. According to endocrinologist Anis Rehman, MD, this is due to the changes in blood sugar levels that diabetes causes. "Paying attention to subtle signs [like irritability] can help diagnose and treat diabetes to prevent diabetic complications," he says.

5
Feelings of Impending Doom: Heart Disease

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A feeling of impending doom can be a sign of heart disease or a heart attack. Laurence Gerlis, MB, CEO and founder of Same Day Doctor in the U.K., explains that this symptom is the result of a loss of oxygen to the brain. And women need to be especially careful: According to the Duke University Health System, women are more likely to experience a feeling of impending doom when they have heart disease or are at risk of a heart attack.

6
Mood Swings: Parkinson's Disease

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Mood swings are a common sign of Parkinson's disease. According to a comprehensive mood changes guide created by The Parkinson's Foundation, that's because the disease is linked to a lack of dopamine, a neurotransmitter that makes us feel good.

When dopamine-producing cells in the brain die, it affects both a patient's movement and mood. In the case of Parkinson's disease, mood swings are a symptom of the illness—not a reaction to the diagnosis.

7
Depression: Parkinson's Disease

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That same dopamine damage that causes mood swings in Parkinson's patients can also cause depression, according to Gerlis. What's more, the Parkinson's Foundation guide notes that depression can occur at any stage of the disease—even before a diagnosis. Many people experience the symptom years before they begin to exhibit the motor issues more commonly associated with Parkinson's.

8
Mood Changes: Digestive Disorders

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According to Heather Hagen, LMFT, clinical director at Newport Academy, digestive disorders that affect your body's ability to absorb necessary nutrients—conditions like celiac disease and inflammatory bowel disease (IBD)—can cause mood changes and even depression. That's because, as Johns Hopkins Medicine explains, the brain and the gut interact extremely closely. When digestive disorders cause irritation in the GI tract, this "send[s] signals to the central nervous system that trigger mood changes."

9
Anxiety: Menopause

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Jordanna Quinn, DO, medical director at Kore Regenerative Medicine in Colorado, says that when middle-aged women begin to experience anxiety, it may be a sign of looming menopause—even if they continue to have regular menstrual cycles. "Often, women will experience changes in their mood prior to their cycle changing," she explains. According to Cleveland Clinic, this anxiety is caused by the changes in hormone levels—specifically in estrogen and progesterone—that occur during perimenopause and menopause.

10
Disorientation: Lung Disease

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"Patients with chronic lung disease are at an increased risk of confusion and disorientation," says pulmonologist Ragheb Assaly, MD. "For example, when patients with chronic obstructive pulmonary disease (COPD) get pneumonia or infections, they develop worsening oxygen levels in the blood," he explains. "This is a known cause of confusion."

11
Apathy: Alzheimer's Disease

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"Apathy, or loss of motivation, is arguably the most common change in behavior in Alzheimer's disease but is underrecognized," note Kent State University researchers in a pivotal 2001 paper published in the Journal of the American Geriatrics Society. This mood change goes hand in hand with the cognitive changes Alzheimer's patients experience, and it's caused by the same neurological issues.

12
Irritability: Huntington's Disease

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According to December 2012 research published in Psychiatry Research, irritability is a common symptom of Huntington's disease. Huntington's causes the deterioration and death of cells in certain areas of the brain. Damage to one brain region in particular—the caudate nucleus—can affect a person's ability to control their emotions, thereby making both irritability and emotional outbursts common among Huntington's disease patients.

13
Extreme Happiness and Sadness: Bipolar Disorder

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Bipolar disorder is characterized by extreme mood swings. Emin Gharibian, PsyD, founder and director of Verdugo Psychological Associates, explains that bipolar patients have an imbalance in several neurotransmitters, which causes them to experience mood fluctuations.

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