- 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.