Antidepressants That Cause Weight Gain: What You Need to Know

When you start taking an antidepressant, a medication used to treat depression and some anxiety disorders by balancing brain chemicals. Also known as antidepressive drugs, these are often life-changing—but they don’t come without trade-offs. One of the most common but rarely discussed side effects is weight gain, an increase in body mass that can happen gradually over weeks or months. It’s not just about eating more. It’s about how your brain, metabolism, and appetite respond to the drug. And yes, some antidepressants are far more likely to cause this than others.

Not all antidepressants are the same when it comes to weight. For example, paroxetine, a common SSRI often prescribed for depression and panic disorder, is known to cause noticeable weight gain in many users, sometimes more than other SSRIs like sertraline or fluoxetine. Then there’s mirtazapine, an atypical antidepressant that boosts appetite and slows metabolism, which is practically designed to make you hungry. People on mirtazapine often report gaining 5–10 pounds in the first few months—not because they’re lazy, but because their brain is literally telling them to eat more. Other culprits include amitriptyline, imipramine, and some SNRIs. If you’re already struggling with body image or have a history of eating issues, this isn’t just a nuisance—it’s a real concern.

Why does this happen? It’s not just one thing. Some antidepressants increase cravings for carbs and sugary foods. Others slow down your metabolism. A few mess with your hormones or make you feel too tired to move. And sometimes, it’s not the drug itself—it’s that you finally feel better, so you start eating again after months of losing your appetite. That’s progress, but it can still lead to weight gain. The key is knowing which drugs are more likely to cause this, so you can talk to your doctor before starting—or switch early if it becomes a problem.

You don’t have to accept weight gain as unavoidable. Many people manage it by adjusting their diet, adding movement they enjoy, or switching to a different medication. Some antidepressants, like bupropion, are actually linked to weight loss. If you’re on one of the drugs known for weight gain and it’s affecting your health or confidence, you’re not alone—and you don’t have to stay stuck. Below, you’ll find real comparisons of antidepressants, their side effects, and what others have done to take back control without giving up their mental health treatment.