The three antidepressants most likely to make you fat – and the two that are the most slimming, according to major study

They are blamed for a whole range of complaints, from insomnia to sexual problems.

But a new large study appears to provide evidence of another side effect: weight gain.

Harvard researchers studied prescription data from nearly 200,000 American adults and found that those who took the tablets escitalopram, paroxetine and duloxetine gained up to 3 pounds after two years of use.

People taking these drugs were 10 to 15 percent more likely to gain at least five percent of their starting weight, compared with users of five other common antidepressants, such as sertraline.

By comparison, other drugs, such as duloxetine or Cymbalta, were only associated with a one-pound weight gain over a two-year period.

All eight drugs studied were associated with some weight gain over a two-year period.

However, the least weight gain was seen in patients taking bupropion or Wellbutrin — one of the three non-SSRI drugs studied — who added less than a pound to their waistline.

Only duloxetine and paroxetine were associated with no weight gain at all after six months.

The researchers compared weight changes 6, 12, and 24 months after starting one of eight common antidepressants: sertraline, citalopram, escitalopram, fluoxetine, paroxetine, bupropion, duloxetine, and venlafaxine.

All participants were not allowed to have taken antidepressants in the six months prior to the study. However, it was not possible to confirm whether prescriptions for these medications had been written before that time.

Although anecdotal reports of weight gain are common, the FDA has doesn’t quote it as an official side effect of most SSRIs.

One in ten Americans takes antidepressants and these medications are a very effective way to treat depression and anxiety disorders.

A study earlier this year found that the number of antidepressant prescriptions given to young adults and teens has increased by nearly 64 percent since 2020.

Dr. Joshua Petimar, a professor in the Department of Population Medicine at Harvard Pilgrim Health Care Institute and co-author of the new study, said of the findings: “Patients and their clinicians often have several options when first starting an antidepressant. This study provides important real-world evidence regarding the amount of weight gain that can be expected after starting some of the most common antidepressants.

“Physicians and patients can use this information, along with other factors, to make the right choice for them.”

The study, published in Annals of Internal Medicine, did not use a control group, comparing weight gain with that of someone who did not take the drug.

This means that the small weight gain over a two-year period could be due to chance or to the mental health problem itself.

Dr. Petimar and fellow researchers from Harvard Medical School and Harvard Pilgrim Health Care Institute analyzed prescription data from eight U.S. health systems that are part of PCORnet, the National Patient-Centered Clinical Research Network.

They studied 183,118 adults between the ages of 18 and 80 who had recently started taking one of eight common antidepressants.

After six months of use, patients taking escitalopram, paroxetine, and duloxetine gained about 0.66 to 0.88 pounds more than sertraline patients — and were 10 to 15 percent more likely to gain at least 5 percent of their starting weight.

Dr. Jason Block, lead author, an internist and professor at Harvard Medical School, said: ‘While there are several reasons why patients and their doctors choose one antidepressant over another, weight gain is a major side effect that often leads patients to stop taking their medication.

“Our research showed that some antidepressants, such as bupropion, are associated with less weight gain than others. Patients and their clinicians may consider weight gain as a reason to choose a medication that best suits their needs.”

It is thought that some antidepressants increase appetite, causing a person to consume more calories.

Selective serotonin reuptake inhibitors are the most commonly prescribed type of antidepressant.

Common SSRIs include fluoxetine, citalopram, sertraline, paroxetine, and escitalopram.

Doctors also often prescribe serotonin-norepinephrine reuptake inhibitors (SNRIs). Common SNRIs include venlafaxine and duloxetine.

Bupropion, or Wellbutrin, is a norepinephrine/dopamine reuptake inhibitor (NDRI).

It’s not fully understood how these drugs control anxiety and improve mood, but experts believe it’s because of the way the drugs affect key hormones in the brain.

SSRIs specifically increase serotonin levels in the brain by inhibiting the reuptake (absorption) of serotonin into brain cells.

This makes more serotonin available, which improves the transmission of messages between neurons.

SNRIs, meanwhile, increase levels of both serotonin and norepinephrine in the brain. They inhibit the reuptake of these two neurotransmitters, making them more available to improve communication between neurons.

Increasing levels of these neurotransmitters is said to reduce anxiety, improve mood, and increase overall emotional well-being.

Other known side effects of antidepressants include nausea, dizziness, restlessness, and sexual dysfunction.

Some patients report that their sexual problems persist for years after they stopped taking SSRIs. However, large-scale, high-quality studies have not yet proven this definitively.

Psychiatrists claim that antidepressants are highly effective in treating mood disorders. Some studies suggest that the pills saved at least 30,000 Americans from suicide between 1988 and 2002 alone.