Patients with depression often tell me that they can't be depressed, because they have nothing to be sad or feel down about. Of course, one of the most troubling aspects of depression is exactly that—it can make people feel blue or otherwise alter their happier disposition for no apparent reason.
The changes in brain chemistry responsible for what we call depression, anxiety, and related syndromes are still not completely understood. But several recognizable triggers for depression, sadness, and low mood have been identified.
Let's start with factors that generally are not easily controlled, although they can often be managed or treated:
Short days with reduced sun exposure. Most people have heard of seasonal affective disorder, or SAD. "Affect" refers to mood, and SAD refers to the low mood that afflicts many people during the winter months. SAD appears to be directly due to reduced exposure to sunlight during the shorter days of winter. Technically, a diagnosis of SAD applies to patients who experience symptoms of depression only during the winter months. In reality, though, many patients with year-round chronic depression feel worse in the winter, too, and even people without depression or SAD tend to have lower mood over the cold, dark, wintry days.
Stress. This is an obvious one, but needs to be mentioned to make the list more complete. There are many possible sources of stress, all of which can cause or worsen depression, anxiety, and even panic. A partial list includes issues related to work, school, family, friends, other relationships, money, sex, moving, and holidays. A longstanding myth suggested that the December holidays were a common time for suicide. That turns out to be untrue, but the stresses of the season can certainly pile up for many people.
Trauma. Intense physical or emotional trauma or abuse can lead to years and years of depression and other psychological problems, a condition called post-traumatic stress disorder, or PTSD. This was first described in "shell-shocked" or "battle-fatigued" veterans, but has since been recognized in victims of rape and abuse, as well as in survivors of natural or man-made disasters.
Bad news. Sometimes we get depressed for a very specific reason, such as the death of a loved one or the loss of something that's important or valuable to us. Anniversaries and other reminders of sad events can also trigger depression.
Genetics. Multiple studies have shown that genetic factors play a role in depression, and in fact mood disorders tend to run more strongly in families than many other medical conditions. So, if one or more of your relatives has ever suffered from depression or a mood disorder, you may be more susceptible to the problem yourself. Importantly, this of course doesn't guarantee that you'll become depressed, but it is something for you to watch out for. And, conversely, you can still develop depression even without a family history of mood disorder.
There are also several causes of depression that, once recognized, are often fairly simple to correct:
Hypothyroidism. Deficiency of thyroid hormone is among the most common of all health problems. The diagnosis is frequently missed unless someone (the doctor, the patient, a family member) specifically thinks about it. Many symptoms can help identify hypothyroidism, such as fatigue, weight gain, and hair loss. But sometimes depression is the only clue to an underactive thyroid gland. Once this diagnosis is established, a prescription for thyroid hormone may be all that's necessary to disperse the dark clouds and brighten a patient's mood.
Changes in estrogen and testosterone. Menopause, when a woman's estrogen levels fall and she stops having her menstrual cycle, is often accompanied by mood swings and depression. Men with low testosterone levels also tend to become depressed. There are some risks to taking supplemental estrogen or testosterone, but correcting that deficiency can work wonders for some depressed patients.
At the other end of the lifespan, adolescents entering puberty—when the sex hormone levels are rising—are very prone to emotional outbursts, depression, and personality changes. There isn't any treatment or cure for puberty, but fortunately it only lasts for a few years, and there are ways of dealing with the mood swings if necessary.
Other hormone deficiencies. Low levels of growth hormone or cortisol can also cause depression. These deficiencies are quite rare, but are worth discussing with your doctor if you have depression, especially if it is proving difficult to treat.
Vitamin D deficiency. We used to think that this critical vitamin was necessary only for healthy bones. But vitamin D deficiency is turning out to be a factor in many other diseases, including depression. A simple blood test is all it takes to check your level of 25-hydroxy-vitamin D. Anything under 35-40 is probably worth treating with extra vitamin D, particularly if you have depression or low mood.
Alcohol. People tend to feel loose and uninhibited when they drink alcohol. And many people drink alcohol to help them forget their problems or to escape temporarily from their depression. But alcohol slows brain function and directly worsens depression, so it is best to avoid alcohol, or at least minimize, your consumption of it if you have a mood problem.
Medications. Every medication comes with a list of potential side effects, and depression frequently appears on those lists. One group worth particular mention is the beta-blockers, which are commonly used to treat high blood pressure, a variety of heart problems, and a few other medical conditions. Examples include propranolol (Inderal®), atenolol (Tenormin®), and metoprolol (Lopressor®; Toprol®). Beta-blockers directly reduce the action of adrenaline, so it should not be a surprise to learn that they can cause or worsen depression. It is important to realize that most patients on beta-blockers do not suffer depression, so it is not necessary to avoid these medications if you haven't actually experienced a side effect.
Also, it can be extremely dangerous to stop a prescribed medication on your own without medical supervision. If you think your depression is being caused by a beta-blocker or any other of your medications, I urge you to discuss your concern with your doctor before making any changes.
This is certainly not a complete list of all possible causes of depression, but it introduces some of the more common ones. What additional factors have been important for you and your friends and relatives?
