For the brain to function well, the body needs to function well. If your body operates at a less-than-optimal level, your brain (and your mood) can be affected.
- Medical Illness
- Drug Treatment
Brain diseases. Some illnesses affect the brain directly. Diseases such as Alzheimer’s disease and Parkinson’s disease affect brain function in ways that increase the risk of depression.
Other medical illnesses. Depression can occur as part of a medical problem, forexample, hormonal problems (such as low thyroid hormone), nutritional deficiencies, immune-system diseases (such as lupus), cancer and infections (such as hepatitis). These illnesses may have a direct effect on the brain, or may cause depression because of the stress associated with the disease. Fortunately, most people with these illnesses do not become clinically depressed.
Depression as the first sign of illness. Depression may be the first symptom of a medical illness. When evaluating someone for depression, doctors routinely check whether a medical illness is influencing the mood change. By asking about your medical history, doing a thorough physical exam and sending you for routine laboratory tests, doctors can exclude major medical causes of depression. In some cases, doctors must monitor your symptoms over time to make a diagnosis.
Drugs can affect the brain and the organs that support the brain. Which drugs? Because of the connection between hormones and mood, the following drugs that change hormone levels can also change mood:
- Corticosteroids are related to the hormone cortisol, and are prescribed for a variety of illnesses, such as arthritis, neurological illnesses, cancer and allergic reactions.
- Anabolic steroids are used by some athletes and body builders to improve performance or power. These potentially dangerous drugs can cause changes in mental state. Common changes are depressed mood or irritability (often called “roid rage”).
- Tranquilizers and sedatives can cause depression.
Other drugs, such as blood-pressure medications and antibiotics, occasionally lead to depression, though this is not very common. Be sure to tell your doctor if notice any signs of depression that appear after starting any new drug.
Recreational drugs. Drugs used for “recreation” or as part of an addiction may cause or aggravate depression. For example:
- Alcohol can cause depression, especially if used in excess.
- Stimulants, such as cocaine and amphetamines, can lead to depression when the user stops taking them.
- Excessive marijuana use can cause apathy (laziness, boredom), poor physical and mental functioning and depression.
The cycle of addiction often contributes to depression. Depression commonly accompanies drug and alcohol abuse or dependence for a number of reasons:
- Because of the effect of the substance being abused
- Because of the lifestyle and behavior that surrounds drug-seeking
- Because an underlying depression leads a person to use a substance in the first place