Depression causes feelings of hopelessness, a lack of interest in things you used to enjoy, and an inability to take pleasure in much of anything at all. It can cause physical symptoms like body aches and fatigue, difficulty concentrating, insomnia, and reduced appetite. It can even cause excessive feelings of guilt and worthlessness, thoughts of suicide, anxiety, and perhaps most characteristically, feelings of sadness that just won’t seem to recede.
But depression isn’t the only medical condition that can cause these symptoms. There are also several medical conditions of a physical nature that can cause psychological symptoms similar to those of depression, like hypothyroidism, hypoglycemia, and even vitamin D deficiency. Other mental illnesses, like anxiety and bipolar disorder, can also cause symptoms similar to those of depression.
Hypothyroidism, a condition that affects about 10 million Americans, impairs the ability of the thyroid gland to produce the crucial hormones necessary for metabolic regulation. These hormones affect the way that cells use nutrients to make energy. When thyroid hormone levels are too low, it can have a profound impact on every part of the body, including the brain.
Many of the symptoms of hypothyroidism mimic those of depression, including low mood, weight gain, fatigue, impaired libido, and difficulty concentrating. If you’re also experiencing symptoms like muscle stiffness and cramps, chills, hoarseness, lowered heart rate, and dryness of the hair and skin, you might be suffering from hypothyroidism instead of depression. The good news is that treatment for hypothyroidism is relatively straightforward, and typically requires taking a daily dose of synthetic thyroid hormone.
Hypoglycemia, or low blood sugar, occurs when you’re hungry and can cause symptoms similar to those of depression, especially if you suffer from rapidly changing blood sugar levels on a regular basis. If your blood sugar is up and down every day, it could be a sign you’re developing insulin resistance and may be at risk for Type 2 diabetes.
However, a drop in blood sugar can cause moodiness, irritability, and other depressive symptoms because hunger triggers the stress response. If you think you might be having problems with your blood sugar, eat low-carb, high-protein meals every few hours and consider having a glucose tolerance test and a serum insulin test, also known as a fasting insulin test, to check your insulin resistance levels.
3. Vitamin D Deficiency
Up to 75 percent of Americans suffer from a vitamin D deficiency, and most don’t even know it. While it used to be thought that vitamin D deficiency mostly causes bone problems, it’s now understood that a deficiency of this key vitamin can cause symptoms similar to depression.
Vitamin D doesn’t occur naturally in very many foods, although most milk, orange juice, cereal, and some other foods in the United States are fortified with this vitamin. Your body can make its own vitamin D, but it needs adequate exposure to sunlight to do so. How much sun exposure you need depends on your skin color and where you live — the quality of the sunlight you receive will vary based on your latitude. If you wear sun block or other protective gear, you may not be getting all the sunlight you need. Ask your doctor to check your vitamin D level and make sure you get enough of the nutrient by eating fortified foods or taking a supplement. Aim for about 600 IU of vitamin D a day.
4. Bipolar Disorder
Bipolar disorder is often mistaken for depression because people with this disorder typically cycle through a depressive phase, as well as a manic phase and a period of normality. People experiencing the manic phase of bipolar disorder often don’t feel that they need help, but they might seek help during the depressive phase — and they might seek it from an overworked general practitioner who has little knowledge of psychiatric disorders and may be willing to write a prescription for antidepressants without referring the patient to a psychiatrist. Many people with bipolar disorder spend more time in a depressive state than they do in a manic one.
However, bipolar disorder is best treated with mood stabilizing and anti-manic drugs like Seroquel or Abilify. Antidepressants like Prozac can cause a person with bipolar disorder to go into a manic phase. That can be dangerous, because mania often causes risky behavior like gambling or unsafe sex. When combined with the right medication, however, certain antidepressants might be beneficial for people with bipolar disorder.
5. Anxiety Disorders
Anxiety disorders like PTSD, obsessive-compulsive disorder, social anxiety disorder, and generalized anxiety disorder can cause depression-like symptoms, just as depression can often be accompanied by anxiety. Many patients with an anxiety disorder also suffer from depression, and vice versa. While antidepressants can be used to treat anxiety disorders, many anxiety disorders can benefit from specialized psychotherapy — which can only be administered if an appropriate diagnosis is made.
Depression isn’t the only condition that can cause feelings of sadness, irritability, fatigue, and trouble concentrating. If you’re being treated for depression and your symptoms aren’t abating, it might be worth seeking a second opinion.