September 2, 2011
Dear Mayo Clinic:
What's the difference between just feeling unhappy and down, and being depressed to the point that medication would help? How soon after starting an antidepressant will I know if it's effective or not? How long will I have to be on the medication?
Depression goes beyond feeling down for a few days. It's a much more serious problem that can be identified by a variety of symptoms. For many people diagnosed with depression, antidepressant medications can help. They do take several weeks to work, and it is usually sensible to keep taking an antidepressant for at least a year after symptoms resolve.
Depression — also called clinical depression, major depression and major depressive disorder — is a medical illness that can cause a range of emotional and physical symptoms. A diagnosis of depression is based on having specific symptoms.
The symptom most often associated with depression is a lasting feeling of sadness, emptiness or worthlessness. But depression can also be associated with irritability and frustration. If these feelings persist for two weeks or more, depression could be the source of the problem. People who are depressed may also lose interest in daily life and in activities they usually enjoy. This can be accompanied by fatigue or a loss of energy and inability to finish tasks that are normally easy to do.
The physical symptoms of depression may involve changes in sleep patterns, including problems falling asleep and staying asleep, or sleeping more than usual. Depression can cause appetite changes, too. Some people with depression aren't interested in eating and lose weight, while others have increased cravings for food and gain weight. Other symptoms of depression include restlessness or, alternatively, slowed behavior; difficulty concentrating or making decisions; and, in some people, repeated thoughts of death or suicide.
Antidepressant medications help relieve symptoms for many people with depression. The most common antidepressants fall into the category of selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa) and escitalopram (Lexapro). Medications known as serotonin and norepinephrine reuptake inhibitors (SNRIs) — such as duloxetine (Cymbalta), venlafaxine (Effexor) and desvenlafaxine (Pristiq) — are also frequently used to treat depression.
When people begin taking an antidepressant, they may hope to feel better within a few days. It's unusual, however, for symptoms to decrease in less than a week. Much more common is a two- to four-week time interval before there is a significant reduction in symptoms. In some cases, it can take up to eight or nine weeks.
About 50 percent of people with depression receive complete relief from their symptoms with the first antidepressant they use if that medication is chosen carefully based on their symptoms, medical history and ability to metabolize the selected antidepressant medication. An additional 20 percent will have a good response, with more than half of their symptoms being relieved with the first medication.
That leaves 30 percent who see little or no benefit from the first antidepressant they take. The good news for them is that about half receive significant relief from the second drug they try. So, overall, these drugs can be very effective when prescribed carefully and taken consistently.
When a good response is achieved and depressive symptoms fade, it's important to be cautious about discontinuing medication. Many people relapse into depression if they stop taking their medicine after six months. Taking an antidepressant for one year is more common. But many psychiatrists believe that a two-year duration of treatment with an antidepressant is a more appropriate length of time before tapering off to see if depression has resolved.
Keep in mind that correctly diagnosing and successfully treating depression depends heavily on a person's individual circumstances and medical situation. For long-term relief, it's best to work closely with a mental health professional familiar with depression who can guide your care.
— David Mrazek, M.D., Psychiatry and Psychology, Mayo Clinic, Rochester, Minn.