Why do you gain weight with antidepressants and mood stabilizers?


– Why do you gain weight with antidepressants and mood stabilizers? That’s what I’m talking about today. I’m Dr. Tracey Marks, a psychiatrist and I make a mental
health education videos. Today’s topic is based on
several viewer questions for me to talk about this. The short answer is we don’t
know the full mechanism. But here are two proposed
ways that antidepressants and antipsychotic medications that we use for mood stabilization cause weight gain. I will also talk about
what we do about it. The way these drugs cause weight gain is by blocking histamine 1 receptors. We usually think of histamine as something that is associated with allergies
and your immune response. If you’re exposed to something
your body is sensitive to, you get a histamine response
that can look like itching, runny nose or even shortness of breath. And then you can take an
antihistamine like Benadryl, it slows down that allergic reaction to make you feel better. That’s how it works
though from the neck down. Histamine works differently in your brain. In certain parts of your brain, it’s responsible for wakefulness or the ability to be alert. That’s why if you take an anti-histamine it may reduce your allergic reaction, but if it crosses the blood brain barrier, it can also make you sleepy
because it’s blocking histamine’s stimulating
effect in your brain. There are four histamine receptors, I’m gonna talk about H1 receptors. In your brain, H1 receptors do a lot. They’re involved in the sleep wake cycle, body temperature,
endocrine regulation, pain, cognition and the relevant
one here: appetite. What researchers have seen
is that blocking H1 receptors affect the region in your brain responsible for making you feel full. It’s called the satiety center. We see this with certain
medications like paroxetine, quetiapine and olanzapine. These medications give you the munchies. People can get terrible
carbohydrate cravings on some of these medications But it’s not enough to
say just don’t overeat. It’s because when you tamper
with your ability to feel full, you don’t see your eating
as stuffing down extra food. You’re eating because you’re still hungry. You don’t feel satisfied. This is what happens in the short term. But with some of these medications, there’s a longer-term creep effect where you continue to gain weight. That slow increase in weight over time comes from another effect
of blocking the H1 receptors and that effect is interfering with a process called thermogenesis. Thermogenesis is the
process of producing heat and creating energy by
burning fat and calories. When you burn less fat, it accumulates. The more fat you have, the
higher your body mass index, also called the BMI. And that’s your ratio of body fat to lean muscle tissue. So that increases when you get this decrease in thermogenesis. So that’s histamine blocking. Bad stuff. A second mechanism is
blocking the 5HT2c receptors. This is just a type of serotonin receptor. It’s been shown in mice that if you activate
their 5HT2c receptors, they lose weight because they eat less. And if you block the
receptor they became obese. Many of the newer
antipsychotic medications block this receptor. Of all the antipsychotic medications, the worst offenders when
it comes to weight gain are olanzapine, clozapine and quetiapine. And all three of these drugs block 5HT2c. Some of the serotonin
enhancing antidepressants are more weight gaining than others. Paroxetine and mirtazapine
are heavy hitters because they strongly
block histamine receptors. Many of the medications that
are considered weight neutral may still result in a two kilogram or four pound weight gain. But medications that
cause a lot of weight gain can cause 50-60 or even
70-pounds of weight gain. The research studies like the ones I have in the description, don’t always report this level of weight gain. They may report it as
five to six kilograms. But these are based on 12-week studies. 12 weeks doesn’t allow
for the creeping up effect that you can get with long-term effect of histamine blocking. So that’s the problem,
what do we do about this? The Non-medication approach
is to have a very strict diet and vigorous exercise. The vigorous exercise is to overcome the slowed fat burning
process that I talked about with impaired thermogenesis. We’re talking about a gym workout. This is not just walking your dog. That’s still great exercise, but it’s not really enough
to keep the pounds off. Also, if you’re trying to
offset the fat accumulation, you need to build muscle
that will burn the fat. This would come from resistance training. And you don’t have to
literally go to a gym. You could use your own body’s resistance. There are apps that can help
you create your own workout. Some examples are Zova and Sworkit. Medication options are to add buproprion if you can handle taking that medication. There may be reasons you
can’t take buproprion like you have bipolar 1 disorder or you’ve tried it in the past
and you’ve had side effects. Buproprion does not cause weight gain and some people can even
lose weight with it. In fact, Contrave is an
FDA-approved medication for weight loss. It’s a combination of
buproprion and naltrexone. It came to market in 2014, but in 2018 the company
filed for bankruptcy. So I’m not sure what’s gonna happen with the availability of that drug. Another weight loss
medication is Orlistat. It decreases fat absorption. The average weight loss
in the clinical trials was about 10% of your body weight. Which may or may not be
that significant to you depending on how much you gained. If you gained 40 pounds and
now you’re up to 200 pounds. That means you may only
lose 20 of those pounds. That’s a modest benefit,
but you do have to look at the side effects to
determine if it’s worth it for you to take the drug. The main side effects are
fatty stools and diarrhea. Fatty stools tend to be
bulky, a weird pale color, and are very foul smelling and they have a greasy film on top. And greasy stools don’t flush well. So if you don’t want to offend
the people in your household, you probably need your own bathroom. So some people decline this option. Two other options are metformin which is a drug used for diabetes. You would take this even if
you didn’t have diabetes. You’d be taking it just for weight loss. And then there’s topirimate. That’s a medication that’s used
for seizures and migraines. It helps you lose weight by
reducing your food cravings. But it can have significant
cognitive effects like confusion and memory problems. Keep in mind your illness itself
can also cause weight gain. If you’re depressed, it
can make you inactive and have no energy to exercise. So consider that possibility
before looking to stop or change your medication because you think it’s
making you gain weight. That’s it. Thanks for watching.

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