why does antidepressants make you gain weight?
In: Biology
SSRIs have been known to increase prolactin – the mammalian hormone responsible for production of breastmilk. Prolactin production is also very common in those with hypothyroidism. In men this causes low sex drive and low to no sperm count. In women, milk production, irregular or no periods, etc etc.. Personally, I was starving when nursing, as well as very very slow to lose weight (which is a biological response since losing fact releases toxins into the body and milk). It makes sense to me, as they say they are unsure the exact mechanism of SSRIs that the involvement of the thyroid and hormone production arent well known and could be why certain people have lower thyroid function and more prolactin which may change how calories are processed. I took an SSRI late last year and immediately had breast growth and firming (similar to early pregnancy) and put on 5 lbs within a month. After switching to Wellbutrin, my breasts have returned to normal, but sadly the weight has been difficult to lose (and quarantine isnt helping)
There doesn’t seem to be a good answer as to why people gain weight on antidepressants, particularly SSRIs. Ideas include: eating more now that you feel better because depression can suppress appetite; the medication itself increases appetite; or the medication interferes with metabolism causing your body to process calories less efficiently. I suspect the reason depends on the person, so there isn’t likely one single answer.
One idea I read about addressed the metabolism hypothesis. SSRIs regulate the chemical serotonin in your brain by blocking a receptor the serotonin attaches to. This then increases the amount of serotonin in your brain to be used for other processes, including regulating appetite. The brain is not the only place in your body with serotonin and neural connections. The other place is your gut. Yes, the are neural connections and serotonin all through your digestive system (giving credence to “gut feelings” and “go with your gut”). So the medication is not just working in your brain, but also in your gut. This gut-serotonin system is less understood. So the medication could be interfering with metabolic processes there when it’s blocking serotonin from reaching these receptors in your digestive system, or there could be some other effect of the medication in the gut, either way the result could be weight gain due to metabolic interference.
Edit: I’ve taken SSRIs for years and have experienced this weight gain. I’d like to say that my appetite hasn’t changed much, but I’ve never been studied for it so I don’t know.
Also, stress makes you lose weight. When you are stressed your body burns more resources and doesn’t do the proper maintenance and upkeep.
Why fix a muscle when you might need those calories to run.
This is not the only factor. It is one I don’t hear talked about as much and I think the effects to which stress has a strain on the body that needs to be repaired after is considered.
The power of this effect would vary from person to situation. In an otherwise healthy person this might not have a strong effect and the hormonal changes previously mentioned would be a larger factor.
The main way you gain weight is when you consume more kcal than you need per day, the excess is stored as fat. SSRIs might effect your behaviour around food, but if you were already tracking kcal like a responsible adult, you wouldn’t gain weight at all.
The other culprit might be water retention, not just fat tissue
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