Antidepressants cause minimal weight gain

Antidepressants have helped millions of people cut through the dark fog of depression. Many others try these medications but stop taking them, often because of side effects such as weight gain. A study from a Harvard-based team shows that the amount gained is usually small, and that it differs little from one antidepressant to another.

Earlier studies linking antidepressant use to weight gain were usually small and short. This one, led by researchers with Massachusetts General Hospital's Center for Experimental Drugs and Diagnostics, included more than 19,000 men and women and lasted for a year.

Using electronic health records, the researchers identified men and women who took an antidepressant for at least three months. Medications used included amitriptyline (Elavil), bupropion (Wellbutrin), citalopram (Celexa), duloxetine (Cymbalta), escitalopram (Lexapro), fluoxetine (Prozac), mirtazapine (Remeron), nortriptyline (Pamelor), paroxetine (Paxil), venlafaxine (Effexor), or sertraline (Zoloft). They also identified another 3,400 people who took some other type of medication for a non-depression ailment. Each person's weight was checked every three months for a year.

The researchers chose citalopram as a reference, because earlier studies suggested that it is "average" when it comes to weight gain. In this study, the weight gain experienced by people taking citalopram averaged one to two pounds. Compared to citalopram, the weight gain linked to other antidepressants was small.

Bupropion was associated with the least amount of weight gain, close to none. Two others that also appeared to have less weight gain were amitriptyline and nortriptyline. Amitriptyline and nortriptyline are older drugs. Because newer drugs tend to have fewer side effects, those two aren't prescribed as frequently. At the other end of the spectrum, citalopram caused the most weight gain. Even so, the differences between the drugs were small. The results of the study were published in JAMA Psychiatry.

Not everyone taking antidepressants gained weight. Some actually lost a few pounds.

Tip for choosing an antidepressant

The results of this study indicate that worries about weight gain shouldn't influence the choice of antidepressant for most people. One antidepressant is generally as effective as another. If you need to choose an antidepressant, let cost and potential side effects be your guide.

Many antidepressants are available as generics. Generics work as well as brand name drugs, but cost less.

Here are some tips for choosing a treatment based on common side effects:

• Sexual side effects, such as difficulty having an orgasm. Bupropion may be less likely to cause this side effect. It's also the one associated with the least amount of weight gain.
• Sleepiness. Some antidepressants make you sleepy. If you have trouble falling asleep or staying asleep, taking one of these before bed, like trazodone, might be a good idea. Paroxetine is another good choice.
• Decreased energy level. No antidepressant leads the pack in terms of being more stimulating. Perhaps bupropion or fluoxetine might be a good first choice.

If you start taking an antidepressant, don't expect to see a major improvement right away. It often takes 6 to 8 weeks to see a response to an antidepressant. And don't give up if the first one doesn't work. Trying a different one may do the trick.

Another option to consider is psychotherapy, especially if the first drug doesn't work. People who do not respond to the first antidepressant can often do as well with talk therapy as they would with another drug.

Keep in mind that a small number of people have a condition called atypical major depression. Instead of the more usual problems of decreased appetite and difficulty sleeping, their depression causes an increased appetite and sleeping too much. This leads to weight gain regardless of drug therapy. For them, it's probably best to stay away from an antidepressant that causes even more weight gain.