Is my antidepressant causing weight gain?
Antidepressant medications can be an effective treatment option for a number of different mental health conditions, including depression and anxiety. Many patients who are considering taking antidepressants have questions about if and how they will impact their weight. Dr. Holly Betterly MD, board-certified psychiatrist in Weston, FL, weighs in on this complex topic.
This post is provided for educational purposes only, and does not constitute medical advice. If you have questions, reach out to your doctor for more information.
Struggling with your mental health? Reach out for professional support. Dr. Betterly is a board-certified psychiatrist in Weston, FL dedicated to helping you overcome depression, anxiety, and OCD. She offers appointments at her office in Weston, FL, conveniently located in Weston Town Center, as well as via telehealth. Request an appointment today to start your journey to better mental health.
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Do antidepressants impact weight?
How does depression impact weight?
Will my antidepressant make me gain weight?
What is an antidepressant?
Antidepressants are a category of medications that are frequently used in the treatment of clinical depression. They may also be used to treat other common mental health conditions, such as anxiety or obsessive-compulsive disorder (OCD).
Antidepressants are available in the United States by prescription only. Antidepressants cannot be purchased over-the-counter. They require a prescription from a healthcare provider who is licensed to prescribe medications, such as a medical doctor.
Psychiatrists are medical doctors with specialized training in treating mental health conditions. They have extensive experience with managing mental health medications such as antidepressants.
Antidepressants should only be taken under the careful supervision of a healthcare provider, such as a psychiatrist, who can monitor to ensure that their use is safe, appropriate, and effective.
Antidepressants come in many different forms, including tablets, pills, and liquids to be taken by mouth, as well as patches to be placed on the skin. Many antidepressants are taken on a daily basis, however the frequency at which an antidepressant is taken varies from one medication to the next.
Do antidepressants impact weight?
Antidepressants vary from one medication to another with respect to their potential impact on weight. Some antidepressants are relatively weight neutral, meaning that they generally don’t lead to a significant change in weight. Other antidepressants may have a tendency to cause either weight gain or weight loss. Because of this, rather than looking at the antidepressant category as a whole, we need to look at antidepressant medications individually when we consider their potential impact on weight.
How does depression impact weight?
Depression can present differently from person to person. While weight gain is a common symptom of depression, so is weight loss. When we look at the DSM diagnostic criteria for a Major Depressive Episode, we can see that one of the possible symptoms is either a significant weight loss when not dieting, or weight gain, or a decrease or increase in appetite nearly every day.
The relationship between depression and weight is complex, and something to keep in mind when we notice changes in weight during treatment of depression.
For example, say that a patient experiencing depression has lost their appetite, and in turn, lost a significant amount of weight. They begin taking an antidepressant medication, and with time, they find that they are eating more, and gaining weight. Is this weight gain due to the antidepressant medication that they are taking, or due to the improvement in their depressive symptoms? It can be difficult to determine, and could even be a bit of both.
We may also see the opposite scenario. For example, say a patient experiencing depression is eating more than usual, and has gained some weight. They begin taking an antidepressant medication, and with time, find that they are eating less and losing weight. This could be due to the depression improving, and/or the antidepressant. We may also consider that perhaps the patient has become more physically active now that their depression has improved, leading to weight loss.
Another scenario may be a patient who has gained weight while experiencing depression, and continues to gain weight after starting an antidepressant medication. If the depression has resolved, then it may be more likely that the antidepressant is responsible for the continued weight gain.
Will my antidepressant make me gain weight?
When we are thinking about the potential side effects of a medication, it can be difficult to predict whether a specific individual will or will not experience a given side effect, or to what extent they may experience a side effect.
For example, if “Medication A” carries a known risk of weight gain, it does not necessarily mean that every person that takes “Medication A” will actually experience weight gain- some people may not experience any changes in their weight, or even weight loss.
Similarly, we may know from looking at research studies that “Medication A” may cause an average weight gain of ten pounds. Does this mean that every person taking “Medication A” can expect to gain ten pounds? Not necessarily.
Let’s break this down. An average is a value that best represents a set of data. There are different ways to calculate an average, but one of the most common ways to do so is by calculating the mean. We do this by adding all of the values together, then dividing this sum by the total number of values. When we apply this to our scenario, the mean weight gain is calculated by looking at how much weight each individual participant in a research study gained over the duration of the study, adding all of these weights together, and dividing that value by the number of participants in the study.
If all of the study participants gained a similar amount of weight over the duration of the study, then the average may in fact be fairly representative of the amount of weight a given individual may expect to gain while taking the medication for a similar time period. Other times, however, the participants in a study may have varied significantly in terms of how their weight changed.
Here’s an example: let’s say there are ten participants in a study. Nine of these participants gain one pound. One participant gained twenty pounds. When we calculate the mean weight gain for this group, we get an average of about three pounds. But as we can see, none of the participants actually gained exactly three pounds of weight- the majority gained less, and one person gained significantly more. If we had told the patients to expect to gain three pounds of weight, this prediction would have been inaccurate.
This can work in the opposite direction as well- if most of the participants in a study gained a small amount of weight, but a few people lost a significant amount of weight, you may end up with an average that suggests no change in weight, or even weight loss, despite that not being the most common experience when taking the medication.
It’s also important to consider that research studies examine the impact of an antidepressant on weight over a specific period of time. If the duration of the study was six weeks, then the results of the study may give us an idea about the impact on weight for patients taking the medication for a similar period of time. However, say a patient continues taking this medication for a longer period of time- for example, six months rather than six weeks. It’s possible that the medication only causes weight gain when you first start taking it, and that you may see no further increase in weight as time goes on. However, it’s also possible that the medication will continue to cause weight gain as long as you continue to take it, meaning that the potential weight gain is likely much greater over six months than over six weeks. Whether the weight gain tapers off with time versus continues indefinitely will vary depending on the specific medication.
TLDR: Even when we have data from research studies examining the impact of a medication on weight, it can be difficult to predict how a specific individual’s weight will be impacted when they take the medication.
Which antidepressants cause weight gain?
As we saw above, antidepressants vary in terms of their potential impact on weight, and it can be difficult to predict how a specific individual’s weight will be impacted when taking a given medication. With that said, certain antidepressant medications are generally more likely than others to cause weight gain.
As there are a huge number of antidepressants on the market, we can’t cover all of them here, but we will consider a few common ones. If you are curious about whether a specific antidepressant may cause weight gain, you can review the FDA package insert for the medication.
Some patients may wish to avoid weight gain, in which case an antidepressant that often causes weight gain may not be the best fit. Other patients may benefit from gaining weight, in which case they may be a good choice. An example may be a patient who has been experiencing depression that has led to a decrease in appetite and in turn, weight loss.
When you are discussing treatment options with your physician, let them know about your preferences so that they can help guide you towards options that will be a good fit for your unique health circumstances.
Mirtazapine
One antidepressant than often causes weight gain is Mirtazapine. Mirtazapine is FDA approved for the treatment of Major Depressive Disorder (MDD).
The FDA package insert for mirtazapine indicates that it may cause an increase in appetite, as well as weight gain. In a study, seventeen percent of participants taking mirtazapine reported an increase in appetite, and around seven percent of participants reported a weight gain greater than or equal to seven percent of their body weight. As a reference point, if a one-hundred-fifty pound person gained seven percent of their body weight, this would mean that they gained about ten pounds. The study found that eight percent of the participants taking mirtazapine ultimately decided to discontinue the medication due to weight gain.
Antipsychotics
Antipsychotics are a category of medications that are frequently used in the treatment of psychotic disorders, such as schizophrenia. Some of these medications have also been approved by the FDA as adjunct treatments for Major Depressive Disorder (MDD), such as aripiprazole and brexpiprazole. This means that they may be used in combination with traditional antidepressants.
Antipsychotics are not typically considered to be first-line medications for the treatment of depression, meaning that they are usually not the first option that doctors reach for in depression. So, while they are sometimes used in the treatment of depression as “add ons”, they are not what we are traditionally thinking of when we think about antidepressants as a category. One of the reasons that doctors may be less likely to reach for antipsychotic medications when treating depression is their side effect profiles, particularly their potential to cause weight gain, as well as increases in cholesterol and blood sugar. This can increase your risk for diabetes and heart disease.
Taking a look at the FDA package insert for aripiprazole, we can see that in trials in which aripiprazole was added on as an adjunct treatment to another antidepressant in the treatment of Major Depressive Disorder (MDD), eighteen percent of participants gained greater than or equal to seven percent of their body weight over a six week period. The mean change in body weight was 1.7 kilograms, or about 3.7 pounds.
We can also consider the FDA package insert for the combination of olanzapine, an antipsychotic, and fluoxetine, an antidepressant. This combination medication is FDA approved for the treatment of Treatment Resistant Depression. The package insert indicates that in studies of patients taking this combination medication, the mean (average) weight gain was 8.8 pounds, with twenty two percent of patients gaining greater than or equal to seven percent of their body weight. Two and a half percent of participants decided to discontinue the medication due to weight gain.
Do SSRIs cause weight gain?
Selective Serotonin Reuptake Inhibitors, or SSRIs, are one of the most frequently prescribed classes of antidepressant medications. There are many different types of SSRIs available on the market. Some common SSRIs include sertraline, fluoxetine, paroxetine, citalopram, and escitalopram.
A recent research study published in July 2024 in the Annals of Internal Medicine compared weight change seen with common antidepressant medications. Various antidepressants were compared to sertraline, an SSRI.
Study participants taking sertraline were found to gain an average of around half a pound after a six month period, and around three pounds after a two year period.
Study participants taking fluoxetine saw a similar amount of weight gain to those taking sertraline.
In comparison to sertraline, the study found that weight gain over a six month period was greater for participants taking escitalopram, paroxetine, or citalopram. They also saw this effect with two SNRI medications, venlafaxine and duloxetine. The antidepressant which consistently showed the least amount of weight gain in the study was bupropion.
My antidepressant is making me gain weight, what do I do?
If you are concerned that you are gaining weight while taking an antidepressant, reach out to the healthcare provider who is prescribing the medication to you. When our patients are experiencing bothersome side effects, we want to know about it so that we can discuss options- don’t suffer in silence!
Each person’s individual health circumstances are unique, and your healthcare provider can help you to figure out a plan that works for you moving forwards. For some patients, this could mean switching to a different medication, adjusting the dose, adding an additional medication to help prevent weight gain, or implementing healthy lifestyle changes, such as diet and exercise.
