How Antidepressants Work
Most antidepressants work by changing the balance of brain chemicals called neurotransmitters. In people with depression, these chemicals are not used properly by the brain. Antidepressants make the chemicals more available to brain cells like the one shown on the right side of this slide.
Antidepressants can be prescribed by primary care physicians, but people with severe symptoms are usually referred to a psychiatrist.
Realistic Expectations
In general, antidepressants are highly effective, especially when used along with psychotherapy. (The combination has proven to be the most effective treatment for depression.) Most people on antidepressants report eventual improvements in symptoms such as sadness, loss of interest, and hopelessness.
But these drugs do not work right away. It may take one to three weeks before you start to feel better and even longer before you feel the full benefit.
Do You Need to Switch?
If your symptoms have not improved after three weeks, be candid with your doctor. Your dose may need to be adjusted or the regimen changed.
Many people do not respond to the first antidepressant they try. Also, antidepressants may stop working in a small number of people who have been taking them for a while.
Remember, it can take up to 3 months to feel the full benefit of antidepressant medication.
Brand Name vs. Generic
According to the FDA, there is no difference in the strength, safety, or quality of generic vs. brand name drugs.
But some studies suggest there may be variations in how well generics are absorbed and utilized by the body. If a generic seems ineffective, discuss your concerns with your doctor.
Antidepressant Pitfalls
Even when an antidepressant is working well, patients may be tempted to quit, either because the dosing schedule is inconvenient or because there are unpleasant side effects.
Also, some people with depression don’t improve with antidepressants and must explore other treatment options.
Antidepressant Success
A successful course of treatment usually lasts several months to a year. Don't quit, even if you feel better sooner.
Your doctor can help you develop a convenient routine for staying on your medication - for example, taking your pills with breakfast every day.
Coping With Side Effects
Don't be shy in telling your doctor about side effects. There are often ways to manage them. For example, taking your antidepressant with food can help nausea. If you're having sexual problems, changing antidepressants may help.
If you feel fatigued, try taking your medicine one to two hours before bedtime. If the antidepressant causes insomnia, take it in the morning. Many side effects diminish on their own after a few weeks.
Drug Interactions
Antidepressants used most often today have fewer side effects and drug interactions than older versions. Still, any antidepressant can interact with other medications, and even with herbal or dietary supplements. Drug interactions can lead to more severe side effects and reduce the effectiveness of your treatment.
Let your doctor know about any new prescription drug, over-the-counter medicine, or dietary supplement you plan to take.
Follow-Up Care
It is vital to continue follow-up care while you are on antidepressants.
Relapses are common. Your doctor may advise changing the dose -- or trying a new medication -- if your symptoms return.
Be sure to inform your doctor of major changes in your life, such as losing a job, developing another medical condition, or becoming pregnant.
Antidepressant Myths
Some people worry that antidepressants will leave them robotic. The fact is, antidepressants relieve feelings of sadness, but they do not eliminate your emotions.
Another myth is that you'll need to take the drugs for life. A typical course of antidepressants lasts six to 12 months. Antidepressants are not physically addictive but should not be stopped abruptly.
Benefits of Psychotherapy
Getting psychotherapy while you take antidepressants is the most effective way to treat depression, studies show.
Types of therapy include cognitive behavioral therapy, which focuses on changing negative thoughts and behaviors, and interpersonal therapy, which focuses on your relationships with others.
Depression and Exercise
Exercise releases endorphins, chemicals linked to improved mood and lower rates of depression.
In fact, several studies suggest regular exercise is an effective treatment for mild to moderate depression. Group sessions or exercising with a partner may be particularly helpful.
Reviewed by Louise Chang, MD on April 12, 2011
This tool does not provide medical advice. See additional information: 
© 2011 WebMD, LLC. All rights reserved.
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Additional Resources
Working Out Your Depression
Exercise is an effective but underused treatment for mild to moderate depression. Exercise releases endorphins, which trigger a positive feeling. Try to exercise at least 20 to 30 minutes, three times a week.