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