Do SSRIs cause weight gain?
August 5, 2010 2:09 PM   Subscribe

How do SSRIs cause weight gain?

I have read anecdote after anecdote of Celexa (citalopram) causing weight gain. I have gained 20 pounds since I have been on the drug. I am on 20 mg a day and have been on the drug for a year.

I don't find that my eating habits have changed that much. I can no longer lose weight like I could before I was on Celexa. I am exercising (walking for an hour a day or gym classes) and eating three reasonable meals a day. No fast food. I am eating cereal for breakfast, sandwich of turkey or lean ham on whole wheat for lunch with fruit, and reasonable dinner (lean protein, salad, veg, rice). I do splurge occasionally but most days I am not consuming too many calories.

What is exactly going on with the human body that causes weight gain when taking SRIIs? Does it change the metabolism? Increase appetite? I find that my appetite is the same or less since I've been taking Celexa but I am still gaining weight.

I was not underweight when I began taking Celexa. I was about 20 pounds overweight, but I felt comfortable in my skin. Now I am 40 - 50 pounds overweight. I am thinking quitting Celexa. Actually, I am going to quit but I want to be safe.

more even-tempered and less "crazy"
less time thinking and obsessing over little things
not much bothers me

my libido is nonexistent
I'm fat
I can't remember anything (spacey)
I'm tied all of the time. I can sleep 12 hours a night without problems

Any thoughts or advice would be helpful. I mainly want to know how it affects the human body in relation to weight gain. Thank you.
posted by anonymous to Health & Fitness (15 answers total) 6 users marked this as a favorite
I don't think the answer to this is known with any specificity. If it is, my doctor didn't know about it. Her speculation, which should not be taken as anything more than exactly that, is that changing the serotonin balance very slightly affects basal metabolic rate, satiety triggers, and base movement rate -- meaning people fidget less -- to the tune of around 50-100 net calories a day. That's not a lot; you'd not notice that as substantially less exercise or substantially more food. But it adds up to a half a pound or a pound a month, stealthily.
posted by KathrynT at 2:21 PM on August 5, 2010

I have similar issues with weight gain. Not sure about why it happens. But I will say that you should be able to find a doctor who can work with you to safely select the right drug for you -- you DO NOT need to put up with side effects like lack of libido or weight gain or anything else that is reducing your quality of life just to be less "crazy." If it turns out that you really need to be on medication to manage depression or anxiety or whatever, you should be able to find one that has enough benefits that the side effects are not bothering you too much. A good doctor will be able to help you safely manage trasitions between meds and will be supportive through a process that can be fairly unsettling (switching medications can be not so fun)
posted by cubby at 2:29 PM on August 5, 2010

I gained weight on Celexa because my sweet tooth became insatiable. The thing about it was, I seemed to have no idea that I was eating more, until it was pointed out to me. It was like completely mindless eating. So, are you totally sure that your eating habits haven't changed? If you don't already, keeping a food journal might help.

That said, when I was trying to lose the weight I saw a dietitian, whose own experience and those of other patients was that the weight would creep on no matter how careful you were. She didn't know why, either.
posted by cabingirl at 2:32 PM on August 5, 2010

Crazymeds, your go-to source for people's actual experience with their, um, crazy meds (and I say this as someone who takes two such meds), lists weight gain as Celexa's major drawback. Sadly, the page says:

Celexa's Typical Side Effects: The usual for SSRIs - headache, nausea, dry mouth, sweating, sleepiness or insomnia, and diarrhea or constipation, weight gain, loss of libido. Most everything but the weight gain and loss of libido usually goes away within a couple of weeks.

Crazymeds' forum can be a good place to look for people's anecdotal discussions of how they have dealt with side effects and other drugs they have talked to their doctors about. Of course the down side is that, well, it's a forum on the Internet. You gets what you pays for.

As for the actual biochemical mechanism for the weight gain, I don't see it on that site or anywhere else, but it's clearly a well-documented side effect.
posted by The Bellman at 2:49 PM on August 5, 2010

I was talking to my friend who is a dietician about this recently. She works in a hospital system, so she deals with people on a lot of meds. Her opinion was that SSRIs can definitely mess with your weight and there is not a clear understanding of why/how. You could do a pubmed search to see what sort of articles come up on the topic.
posted by mandymanwasregistered at 2:51 PM on August 5, 2010

I heard one psychiatrist hypothesize that people on Celexa gain weight because they are more likely to be going out with friends, being more social, etc, which are situations that can lead to more eating out and thus weight gain. YMMV.

I'd encourage you to ask a mod to add a throwaway email address for you, because the reason you want to be anonymous is the same reason some folks might not want to respond here.
posted by bluedaisy at 3:52 PM on August 5, 2010

"Approximately 80 percent of the human body's total serotonin is located in the enterochromaffin cells in the gut, where it is used to regulate intestinal movements."

"In the gastrointestinal tract, 5-HT [serotonin] is important in response to chemical, mechanical or pathological stimuli in the lumen. It activates both secretory and peristaltic reflexes,"

I'm guessing it makes the digestion process more efficient somehow. We don't necessarily extract all the calories out of the food we eat. So if this increases peristalsis and secretions in the gut, that would tend to grind up and dissolve the food better, allowing the gut to extract more calories than normal.
posted by gjc at 3:52 PM on August 5, 2010 [1 favorite]

I had the same experience. I suspect this right here is the culprit, at least in part:

I'm tired all of the time.

I was completely exhausted the entire time I was on an SSRI, too tired to move around like I normally would. No fidgeting, no unnecessary movement, no more walking than was absolutely necessary, and tons more sleep than normal.

Being that tired and sleeping so much cost me muscle mass over time, which in turn, made me burn fewer calories while at rest.

It wouldn't surprise me to find out that there's a chemical reason why you gain weight on an SSRI as well, though. My mother described my face as "puffy" on an SSRI, and saw that puffiness disappear within weeks of my stopping it.
posted by Hildegarde at 4:45 PM on August 5, 2010

It's damn strange. I took Lexapro for a year without weight gain or any other noticeable side effect, then switched to the generic citalopram and gained 10 pounds. Also started sleeping more. Same drug, basically, isn't it? What rings true above is the fidget factor. I'm normally a fidgeter, knee-bouncer, finger-tapper, jumper-up-to-pace-the-roomer. I don't do that nearly as much on citalopram, even though I've cut my daily dose to 10mgs by halving the tabs. I'm as calm as the dalai lama. I'm betting the extra sleep combined with the eliminated fidget-factor is the culprit.
I'm glad for the citalopram-imposed calm, but am thinking of getting off the stuff till I drop the 10 extra pounds.
posted by fivesavagepalms at 5:24 PM on August 5, 2010

fivesavagepalms- I had a similar problem with generic zoloft versus regular. Specifically, a generic made by only one manufacturer. More side effects, almost none of the desired effects. I don't know what the reason is, but it was quite surprising that such an obviously different chemical was in there. I'd love to know what the difference was.
posted by gjc at 6:29 PM on August 5, 2010

They don't even really know why SSRIs are effective for depression, so they sure as hell don't know why any of the side effects happen. The answer boils down to: "they mess with your brain and your brain is a complicated piece of meat." Sorry.
posted by kindall at 6:32 PM on August 5, 2010 [2 favorites]

I don't think the doctors even know, since my own doctor and my (google-based) research revealed that scientists don't even know exactly how SSRI's even work. (Like kindall above me said).
posted by 1000monkeys at 9:17 PM on August 5, 2010

Yeah, it's complicated. Most psychiatric medications are something of a shotgun approach in that they tinker with the function of many neurons not of interest and have indirect effects on even more since neurons in the brain talk to each other. Also, as noted above, the enteric nervous system is probably hit. Any story is even more complicated by the observation that escitalopram (Lexapro) doesn't appear to have the same (degree of) effect on weight. Celexa is just 50/50 escitalopram and a stereoisomer (a nearly identical molecule with a different "handedness").

Although it's more expensive, if Celexa appears to work for your symptoms with too much in the way of side effects many MDs will offer to try a switch to Lexapro. A psychiatrist may adjust the dose, or adjust the dose and consider an add-on drug.
posted by a robot made out of meat at 8:00 AM on August 6, 2010

Well, damn. I'm here to echo the 'no one really knows but it seems to happen a lot' answer. I've gained like 30 pounds or so in the years I've been on zoloft, without significant dietary or exercise changes - in fact, I've become a healthier eater during that time. I've talked to my psychiatrist about it, my GP AND another internist and no one seems to know why it happens; they're usually quick to skirt the question, honestly.
posted by Lutoslawski at 9:26 AM on August 6, 2010

If the drug isn't working for you - for whatever reason - talk to your doctor about switching medications. There are other anti-depressents with different side-effects. I switched because SSRI-type meds (specifically Celexa) sapped every last ounce of my energy, and Welbutrin worked really well for me.
posted by aimedwander at 9:30 AM on August 6, 2010

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