Do antidepressants cause weight gain? Why people stop

Pharmacotherapy

Not all weight gain during treatment comes from the medication, and not every antidepressant affects appetite the same way. Why stopping on your own is usually the worst path, and what is worth bringing to your appointment.

October 31, 20269 min read

Illustration for the article: Do antidepressants cause weight gain? Why so many people stop taking them

Her usual jeans won’t button anymore. She tries again, gives up, switches to a looser dress and leaves late for work. It’s been five months since she started the antidepressant. Five months of sleeping better, crying less and having lunch with her coworkers again. And five months of the scale creeping up a little every month.

At her appointment, she talks about sleep, about work, about her mother. About her weight, she says nothing. At home, though, the decision is almost made: if the medication is to blame, she’d rather stop.

Do antidepressants cause weight gain?

Some do, in some people. But simply saying that antidepressants cause weight gain oversimplifies things, and the honest answer has more than one part. The first is that antidepressants are not all alike on this point: some tend to clearly increase appetite, sometimes within the first weeks, and others, for most people, have little effect on weight. The second is that, on the same medication, the response varies a great deal from one person to another.

The third part almost never comes up: not all weight gain during treatment is antidepressant weight gain. Part of it, sometimes a large part, comes from the improvement itself, from sleep, from moving less, from what you drink. Telling one thing from the other is the first step, and that work is done together with your psychiatrist, not alone in front of the mirror.

Sometimes the weight comes back because the depression is leaving

Many people forget that depression also affects hunger. In many cases, it takes the taste out of food, leads to skipped meals, turns lunch into a chore. Weight drops without anyone really noticing, because more urgent things are going on.

When treatment starts to work, appetite returns, and the taste of food comes back with it. Part of what the scale shows, in these cases, isn’t a side effect: it’s the body regaining the weight it had before getting ill. That doesn’t make the gain any less real, but it changes a lot about what it means.

There is also the opposite path. Some depressions increase hunger instead of reducing it, with cravings for sweets, eating at night, sleeping more than usual. And some people eat to ease anguish, almost without noticing. In these cases, the weight sometimes started rising before the medication, and the antidepressant takes the blame for a process that was already under way.

Sleep, movement and alcohol also move the scale

Poor sleep increases hunger. It’s not a lack of willpower: bad nights disrupt the signals the body uses to regulate appetite and fullness, and the result is usually a stronger urge to eat, especially sweet, high-calorie foods.

Depression also reduces movement: fewer walks, less time outside, more hours sitting still. Some medications cause drowsiness, which adds to this. And alcohol counts twice, for the calories it brings and for the brakes it releases around food, besides worsening sleep and mood on the following days.

Then there is what has nothing to do with treatment and happens at the same time: thyroid changes, the transition to menopause, quitting smoking, other medications in use, some well known for affecting weight. Between thirty and sixty, the body changes anyway, and not everything that happens in this period is the antidepressant’s doing.

Some medications affect appetite more than others

That said, the medication’s effect is real and shouldn’t be minimized. Some antidepressants act on brain mechanisms linked to hunger and sleep, which is why they increase appetite, cravings for sweets and drowsiness. That’s the case with older antidepressants, such as amitriptyline, and with mirtazapine, both known precisely for this. In the group most prescribed today, the same group as sertraline and fluoxetine, the effect on weight tends to be smaller and slower, sometimes appearing only after months of use. Within that group, paroxetine is the one most often mentioned when the subject is weight.

There are also the medications that sometimes accompany the antidepressant. Some antipsychotics, which despite the name are also used in treating depression and other conditions, and some mood stabilizers tend to weigh more on the scale than the antidepressant itself. Some of them also affect how the body handles sugar and fat, which calls for specific monitoring.

In every case, the same caveat applies: two people on the same medication can have opposite stories with their weight. The package insert says what can happen, not what will happen to each person.

Stopping on your own is usually the worst path

When weight becomes a concern, the exit that seems simplest is to stop the medication. That’s understandable, and it’s a request that comes up often in my practice. Weight gain shows up every day, in the mirror, in your clothes, in someone’s comment. The improvement in depression is more discreet, and it’s easy to forget where you came from.

But stopping alone usually costs a lot. Abruptly interrupting an antidepressant can bring a malaise of its own, with dizziness, irritability, nausea and sensations similar to small electric shocks, which many people mistake for getting worse. And the depression can come back, sometimes slowly, sometimes all at once. When it does, it brings the disruption in sleep and appetite with it, and the weight gained doesn’t always go away just because the medication was stopped.

There is also a less visible cost. When someone stops in secret, the psychiatrist keeps evaluating a treatment that is no longer happening, and the two end up looking at different things. So it’s worth saying plainly: don’t stop on your own; talk to whoever is following you. Weight is a legitimate reason for that conversation, not vanity.

When weight calls for a reassessment of treatment

If the weight gain is bothering you, or if the urge to stop has already appeared, it deserves to come into the appointment with the same importance as sleep or mood. It helps to bring some information:

when your weight began to change, relative to starting the medication and to the improvement;
how your appetite changed: more hunger, cravings for sweets, the urge to eat at night;
how sleep, movement and alcohol are going;
other medications in use and health changes in the same period;
your weight before the depression, and what this gain means to you;
how much the medication helped, because that is the other half of the equation.

With this, the evaluation can separate what comes from the medication, what comes from the improvement and what comes from elsewhere, looking at the whole picture along with your life history, the diagnosis and previous treatments. What to do from there doesn’t fit in an article. That path is decided in the appointment, with the whole history on the table, and it includes monitoring weight and, when indicated, some lab tests over the course of treatment.

Part of this conversation goes beyond the scale. The relationship with food and with one’s own body often carries a long history, and sometimes food is being asked to do a job that isn’t its own, such as calming, filling, consoling. With psychoanalytically oriented psychotherapy, it becomes possible to think without judgment about what the food is trying to resolve and what the body has come to represent after the depression.

Weight that bothers you deserves to be taken seriously, and so does the treatment that helped. Both fit in the same conversation.

Frequently asked questions

Which antidepressant causes the most weight gain?

The ones most associated with increased appetite and weight are some older antidepressants, such as amitriptyline, and mirtazapine. Among the most prescribed today, the effect tends to be smaller and slower. Even so, the response varies a lot from person to person, and choosing a medication weighs many things besides the scale.

If I stop my antidepressant, will I lose weight?

Not necessarily, because weight gain usually has more than one cause at the same time. Stopping on your own also carries risks that weigh more than the scale, such as the return of symptoms and the malaise of abrupt discontinuation. Only an evaluation can separate what comes from the medication and what doesn’t.

Is weight gain on antidepressants normal?

It’s a known effect of some antidepressants, but it isn’t inevitable or the same for everyone. It can also have other causes, such as appetite returning as depression improves, and that’s why it deserves to be mentioned to your psychiatrist from the start.