Why do anti-depressants make you gain weight?

Why do anti-depressants make you gain weight? Is there something you can do (besides eat less and exercise more) to prevent weight gain from anti-depressants?

how much weight are we talking about, and how long did it take to gain it? I've been on Lexapro for two months and I'm not sure if I gained any weight or not. I don't think I have (yet). My pants still fit, but I do fluctuate 5 pounds sometimes. I haven't been exercising lately at all, so I wouldn't be quick to blame it on the Lexapro in my case if I HAVE gained weight.

I have gained an enormous (unhealthy) amount of weight from AD's. Starting with Effexor and 22lbs in just 6 weeks.

If I could answer why these drugs do this, I would patent the answer and probably become a millionare.

they made me lose weight, too much weight, i looked like i did when i didn't eat, but i was eating, now i've put some weight back on and it seems to have evened out.

AD's made me lose weight....
cuz i had atypical depression where you eat a lot when youre depressed.....
so when i got happy, i ate less.

you know what helps me with my appetite... arizona green tea, and lots of lettuce salad with light dressing...

ok... all you people saying you lost weight are making me more depressed... IM JEALOUS!

<font color="blue">I've never had that problem with anti-depressants, the only drug that ever made me gain wait was Mirtazipine (Remeron) I was on that for 8 months, but after I got off of it I lost all the weight. </font>

Anti-depressants make you gain weight because some of them (Paxil, Remeron, Serzone and the tricyclics like Elavil) block the H1 histamine receptor. By looking at which antidepressants affect the H1 receptor you can directly predict the chances of weight gain. H1 receptor blockade stimulates appetite but doesn't affect your metabolism. Prozac, Celexa, Lexapro, Effexor, Wellbutrin don't affect H1 much thus no weight gain.

esther...T_MD is right...and don't let it go if you are putting on a lot of weight.

This happened to me back in 1994 after I had my son and very quickly. I was put on older medicines and many of them at once I might add.

I don't know if you saw my photo at present time, but you would never think that at one time I had weighed over 358lbs.

I went from 125lbs...never any serious weight problems to over 358lbs and I say over because I just couldn't get on a scale anymore because I felt trapped in my own body. It was awful. Not to mention some of the medicines scarred my face.

Anyway...I'm now on wellbutrin and off many of the medicines I was once on and I have lost well over 160lbs actually probably a lot more then that I've lost count.

Someone else mentioned how doctors sort of don't listen or take seriously what is going wrong, but don't let that go or whatever is really bothering you.

Good luck .

Gotta contradict T_MD -- I gained over fifty pounds on a combination of Effexor XR and Prozac! All came right off after I stopped, thankfully...

EV I gained 30 pound on lexapro
and another 30 pounds on BC not fun at all... *sigH*

Esthersvirtue - Unfortunately, there is not much that you can do about SSRI-induced weight gain. Further bad news is that in most cases the weight gain seems to be irreversible (in my clinical experience). On the upside, SSRI-induced weight gain does seem to be linked to antidepressive effectiveness; at least to a small degree.

The mechanism of SSRI-induced weight gain is still controversial, but there are a number of theories. A journal that I subscribe to, The Journal of Clinical Psychiatry has a section called Brainstorms . This article is a bit dated (1999) but it still has some good info (let me know if you can't access the article and I'll paraphrase). The article ends with: </font><blockquote><div id="quote"><font class="small">Quote:</font>
Hopefully, as the pharmacologic mechanisms of weight gain become better understood, well-designed studies geared toward the development of guidelines for managing weight gain by using combinations of psychotropic drugs will be forthcoming.

</div></font></blockquote><font class="post"> It's six or seven years later, and I'm not sure that we really know that much more about this topic. Here is another Brainstorm article.

Depression itself is associated with weight changes, most commonly weight loss. Therefore, a possible mechanism for weight gain associated with therapy can be due to a return of appetite, which may also explain the tentative link involving weight gain and antidepressant efficacy. The return of appetite can cause unconscious overeating, leading to incidious weight gain. The poundage seems to sneak up, and then one day, for some seemingly inexplicable reason, your pants don't fit.

SSRI-induced weight gain is commonly preceded by a sudden increase of appetite for sweet and fatty foods. "Carbohydrate cravings" are common. After my wife had been on Paxil™ (paroxetine) for 4 weeks we began to have potato chips, pretzels, and glazed doughnuts in our cupboard. For 12 years of marriage we never had any junk food in the house, and then it seemed that we had a lot of it, and it kept getting replaced when it would disappear. I did mention it to her, but she just brushed me off (and I didn't push the point because I thought she'd stop buying it). She has gained 15 to 20 kg (approx. 30 to 45 lbs) over the past 4 years, even though she switched from Paxil to Effexor XR™ (venlafaxine). She has tried everything to get the weight off and nothing seems to help (she says that exercise just makes her hungry). The carbohydrate craving with Paxil is probably due to the drug blocking histamine-H1 receptors, as well as stimulating serotonin-5-HT2C receptors.

More than likely it is a combination of neurotransmitter changes effected both directly and indirectly by the antidepressant. SSRIs may interfere with the function of specific central nervous system feedback systems regulating appetite and food intake. Alpha-adrenergic neurotransmission is thought to stimulate appetite, while beta-adrenergic, histaminergic, dopaminergic, and serotonergic receptor blockade results in satiety. Drugs which possess anticholinergic properties may cause dry mouth and increased thirst. Patients drinking high calorie drinks (soda pop) to quench their thirst may have significant weight gain. So the potential for certain drugs to affect these systems may explain the associated weight gain.

A decrease in resting metabolic rate also plays a role in weight gain. Basal energy turnover can account for as much as 70% of daily energy expenditure. A small change in this basal metabolic rate may have a considerable impact on body weight.

One thing that I have found that has helped some people keep the weight from piling on in the first place is to start a food journal/diary when one starts an SSRI. It is easier to notice increased food intake when you are paying attention to your eating habits. On the downside, a food journal can be a bit of a bother to keep up, and it doesn't make you any less hungry.

Sorry that I can't help anymore than this. - Cam

Meds, weightgain............sux.............we have 2 choices. Don't take meds, get sick, be thin........or.........take meds, be well, be fat..........I hate being overweight &amp; continually getting larger, but I hate being sick too. Some choices hey!!!!!
Good luck in the battle of weight control!!!!!!!!!!!!

Kezzz

well, my take on it is that i'd rather be fat and happy than thin and dead..................