DEAR DOCTOR K:
I’ve been feeling down and moody lately, but nothing out of the ordinary has happened in my life. And I’ve always been a happy and positive person. Could something other than depression be affecting my mood?
Depression is a common problem, and it often is not recognized by either the person suffering from it or that person’s doctor. In fact, I think undiagnosed and untreated depression is one of the most important health problems in the developed nations. It generates enormous emotional suffering — on the part of the depressed person, and that person’s family, friends and co-workers. It also leads to lost productivity.
But while under-diagnosed depression is a big problem, “over-diagnosed” depression also is a problem. Mood disturbances can be caused by a variety of medical conditions or medications. Indeed, this may be true in up to 15 percent of all cases of depressed mood. When the medical condition is treated, or the medication stopped, the mood disturbance goes away. Yet doctors sometimes misdiagnose such cases as “depression.”
Among the best-known medical conditions that can cause a depressed mood is a thyroid hormone imbalance. Too little thyroid hormone, called hypothyroidism, often leads to depression-like symptoms. Nutritional deficiencies, such as a lack of vitamin B12, can mimic depression. Heart disease has also been linked to depression.
The following medical conditions also are associated with mood disorders:
- multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, Huntington’s disease;
- certain hormone deficiencies, such as Addison’s disease;
- certain immune system diseases, such as lupus;
- some viruses and other infections, such as mononucleosis, hepatitis and HIV;
Sometimes, it’s hard to tell which came first, the medical condition or the mood changes. Each of the above conditions can cause a depressed mood, and the stress of a serious illness can trigger depression.
A doctor can help tease out whether mood changes occurred on their own, were caused by a medical illness or were the result of the medical illness. To do so, he or she will consider your medical history and the results of a physical exam and other tests.
If depression springs from an underlying medical problem, the mood changes should disappear after the medical condition is treated. But in many cases, though the episode may be triggered by the medical illness, the depression becomes an independent problem. Therefore, treatment must also address the depression directly.
Medications can also cause a depressed mood by directly impacting brain circuits that regulate mood. Here is a detailed list of the medicines that most often affect a person’s mood:
Medications that may cause depression
The following medications can affect mood in some people.
Antimicrobials, antibiotics, antifungals, and antivirals
Heart and blood pressure drugs
Your doctor can help sort out whether a new medication, a change in dose or drug interactions might be causing your problems. Or whether, like millions of other people, you are suffering from depression. Diagnosing depression is the first step to getting treatment, and the treatment is effective in the great majority of cases.