weight-gain

Are you taking or considering taking an SSRI antidepressant like Paxil, Prozac or Zoloft – and are you worried about the potential for weight gain?

The bad news is that you have reason to worry.  The good news is that most of the weight gain takes place over time, and that it doesn’t necessarily happen that often.

Let’s go through the details.

And for some useful ideas on how to fight weight gain, see The Top 10 Ways to Lose Weight.

The SSRIs and Weight Gain

First, you should know that weight gain is a possible and common side effect from antidepressants.  But how common is it?

An article on WebMD puts the incidence of weight gain on SSRI antidepressants in general as high as 25%.  That means that one out of four people taking them will gain weight.

Yikes!   Fortunately, the article also says that the weight gain may occur over use for more than 6 months.

That it takes some time for the weight to develop might explain why some studies have not shown it to be an issue.  A study that runs for just a month might not catch any weight gain, especially since it takes a while to develop.

So you can gain weight from antidepressants.  The confusing part?  You can also lose weight from them.  What’s it all mean?

It’s hard to say.  Scientific research is very limited into the side effects of a medication.  This makes it quite hard to figure out how common weight gain from SSRIs is and how much weight occurs in general.

On the one hand, you anecdotally hear about it all the time.  On the other, it is very hard to find actual scientific analysis of the issue.

Zoloft weight gain

Plugging the search phrase “Zoloft weight gain” (or rather the technical phrase “sertraline weight gain”) into a medical research database shows only 42 results, and very few of those actually discuss the issue.  This is despite millions of people taking that medication.

Prozac weight gain

Things look better for “Prozac weight gain” (166 results), but many of those results are dealing with a combination of Prozac and Zyprexa, not Prozac alone.

Paxil weight gain

Searching for “Paxil weight gain” finds only 71 results, and the vast majority of them have nothing to do with the subject directly.

Issues with the scientific research?

It is possible that the possibility of weight gain from antidepressants is overlooked due to how research is conducted.

We looked at a major analysis that was, on the surface, dedicated to finding the side effects from Zoloft.  Yet we searched through it and could not find a single time the word “weight,” meaning it completely missed both the possibility of weight gain and weight loss.

If other research studies similarly ignore the possibility of weight gain or loss, it is likely that it will be overlooked.

Still, we found some hints of data that may clarify the issue.

Side effect database

We ran Zoloft, Paxil and Prozac through a medical database dedicated to reporting of side effects.

Zoloft: No numbers on weight gain, but weight loss is a reported side effect

Paxil: No numbers on weight gain, but up to 1% report weight loss

Prozac: No numbers on weight gain, but up to 3% report weight loss

It’s somewhat odd that there are numbers reported for weight loss from antidepressants while weight gain, which is likely much more common, has no numbers directly associated with it – that we could find.

Next, we looked at an analysis of 700 patient reports.  The reports were generated on a site that allows patients to report side effects from medications.  Of those 700 reports, 49 said that weight gain was a side effect.  That’s about a 7% rate of weight gain.

One clinical study of several hundred people with major depression indicated that Paxil was associated with significant weight increase, Prozac with a modest, not-significant weight loss, and Zoloft with a minor and not significant weight gain.

Is Prozac or Zoloft more effective?

You may be confused because you don’t know what the differences between Prozac and Zoloft are.  For a head to head comparison of them, see here.

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