Image: How to reverse weight gain from antipsychotics

The use of antipsychotic drugs in the United States has been steadily increasing since the 1990s, especially among kids. And although these medications can help people live fuller lives, they tend to have undesirable side effects.

One of these is weight gain. And one of the common antipsychotic drugs that can cause this dreaded side effect is risperidone, also known by its brand name, Risperdal. Aside from putting on additional weight, however, users of the antipsychotic medication also experienced other side effects that were serious and for which they weren’t prepared.

For instance, complaints in the Risperdal lawsuit allege that young male users of the atypical antipsychotic developed a condition called gynecomastia. This is a disorder in which there’s an enlargement of the breast tissue in men or boys.

Some users of risperidone who developed the condition even lactated. Other children who took the drug also gained weight rapidly.

And while this can be a frustrating adverse effect, know that you should go easy on yourself. After all, you’re facing an illness.

The good news?

Studies have shown that there could be ways to lose the unwanted pounds caused by your medication. Continue reading the article to learn more.

How do antipsychotics cause weight gain?

Antipsychotic-induced weight gain is tied to appetite changes. Antipsychotics tend to stimulate hunger and thirst and can cause food cravings.

This is because these medications affect the way your brain and hormone both work to control your appetite. People undergoing antipsychotic treatment often crave sweets and fatty foods.

In fact, the prevalence of obesity and diabetes among individuals with schizophrenia and schizoaffective disorders is 1.5 to 2 times higher compared to the general population. In recent years, however, this risk has been increasing. And some of this increased risk is linked to the use of second-generation or atypical antipsychotics.

What’s worse?

Obesity and diabetes are both risk factors for cardiovascular disease. This is why more than two-thirds of people with schizophrenia die of coronary heart disease, as compared to about 50% of the general population.

Battling Weight Gain from Antipsychotic Drugs

People are more likely to rapidly gain weight within six months after starting antipsychotic treatment. It’s still possible to gain more weight after this period, but more slowly.

In reversing antipsychotic weight gain, several studies have shown that the diabetes drug metformin, as well as lifestyle changes, can promote weight loss for patients who gained weight on antipsychotic medications.

What is metformin used for?

Metformin is a medication used to treat type 2 diabetes. It also helps you prevent type 2 diabetes if you’re at an increased risk of developing it.

Type 2 diabetes is a condition where the body doesn’t make enough insulin or the insulin it makes doesn’t work properly. Ultimately, this can cause high blood sugar levels or hyperglycemia.

It’s usually prescribed for this illness when diet and exercise haven’t been effective in curbing your blood sugar levels. Metformin is also used off-label as a treatment for polycystic ovary syndrome (PCOS), gestational diabetes, and prediabetes.

In countering antipsychotic-induced weight gain, Metformin is the most extensively studied drug. Although it’s not a weight-loss drug, researchers have found a link between Metformin and weight loss.

For instance, a long-term study conducted by the Diabetes Prevention Program concluded that the medication could be indicated as a treatment for excess body weight. However, more studies are needed to prove this.

The exact association between metformin and one’s weight is still unclear, but many theories provide potential explanations for the weight loss that it causes. According to the Mayo Clinic, reduced hunger is one side effect of the drug. For instance, it can affect hunger cues.

Lifestyle Intervention

Significant weight gain is one of the dreaded side effects of antipsychotics. It’s more evident, however, with the use of newer atypical antipsychotic drugs. This side effect is also one of the reasons why individuals suffering from psychosis die up to 30 years earlier than the general population.

Recent studies suggest that lifestyle intervention helps reverse weight gain induced by antipsychotic medications. Some approaches include:

  • Changes in diet
  • Increased physical activity
  • Changes in eating behaviors

Limiting portion sizes and cutting down on beverages and foods that are rich in sugar and fat can also be helpful in this approach.


The interest in the likelihood of antipsychotics to cause weight gain was awakened after the first meta-analysis on the subject was published. The study evaluated weight gain caused by both first- and second-generation antipsychotics at standard doses in a span of 10 weeks.

The study found that patients on placebo lost a certain amount of weight. However, most patients on antipsychotics have gained weight.

For instance, a mean weight loss of about 0.39 kg was reported with the use of molindone, a first-generation or typical antipsychotics. On the other hand, significant weight gain ranging from 4.45 to 2.10 kg. was reported for the following medications:

  • clozapine
  • olanzapine
  • chlorpromazine
  • sertindole
  • thioridazine
  • risperidone

After this study, subsequent research and meta-analyses followed suit in confirming these findings.

Randomized Controlled Trial in China

This randomized controlled trial was conducted in China and involved 128 adults with ages ranging from 18 to 45 and was newly diagnosed schizophrenic patients.

The participants in the study had all gained over 10% of their body weight during their first year of treatment with clozapine, olanzapine, risperidone, or sulpiride (not approved for use in the United States).

All participants were randomly assigned treatment options, including metformin use alone, metformin with diet/exercise, inactive placebo alone, or inactive placebo with diet/exercise.

After 12 weeks, the study authors found that:

  • Patients who were assigned treatment with placebo alone gained 6.8 pounds. Their waist size grew by almost an inch.
  • Those assigned to a placebo with diet/exercise lost around 3.1 pounds. Their waist size was reduced by nearly an inch.
  • Individuals who were on metformin treatment alone lost 7.1 pounds. The size of their waist shrank by a half-inch.
  • Patients who were assigned to metformin with diet/exercise managed to lose 10.4 pounds. Their waist size shrank by almost an inch.

Ren-Rong Wu, MD, of Central South University in Changsha, China, together with colleagues, reported the findings in The Journal of the American Medical Association (JAMA).

“Lifestyle intervention and metformin alone and in combination demonstrated efficacy for antipsychotic-induced weight gain,” Wu and colleagues conclude. “Lifestyle intervention plus metformin showed the best effect on weight loss. Metformin alone was more effective than lifestyle intervention alone.”

Patients involved in the study recently started low-dose antipsychotic treatment. None of the patients had yet become obese, as well. As a result, it’s not clear whether obese individuals or those on long-term, high-dose treatment with antipsychotics can also possibly benefit from metformin treatment.


Lead author Carla Green of the Center for Health Research at Kaiser Permanente Northwest in Portland, Oregon, and her team studied 200 individuals who’ve been taking antipsychotic medications for at least a month.

The participants also had a body mass index (BMI) of at least 27. BMI is a measurement of a person’s weight with respect to their height.

Green and her team explained in the American Journal of Psychiatry that the patients were randomly assigned to an intervention group where participants attended a new program or a comparison group where individuals only got their usual medical care.

In the intervention group, patients attended two-hour group meetings per week within the first six months of the study. During each session, participants got to meet mental health counselors and nutritionists. Each meeting also included 20 minutes of physical activity (walking).

Moreover, participants also monitored their food intake, calories, and the amount of their physical activity. Each day, the goal was to have at least 25 minutes of moderate activity.

The intervention focused on the following to achieve changes in behavior, activity level, and weight:

  • An improved diet with more fruits and vegetables
  • Moderate reduction of calories
  • Limiting portion sizes
  • Increased low-fat dairy products and fiber intake
  • Increased physical activity
  • Stress management
  • Improved sleep


In the second half of the year, the participants met to talk about strategies for maintaining weight loss. The comparison group, on the other hand, didn’t participate in the intervention program for weight loss and maintenance.

In the end, findings of the study indicated that:

  • Participants in the intervention group lost an average of 10 pounds within the duration of the study.
  • 40 percent of participants in the intervention group cut down five percent of their initial body weight. 18 percent of them also lost 10 percent of their initial weight.
  • Within a year, fasting blood sugar levels went down in the intervention group, but increased for the comparison group.

The Bottom Line

Weight gain is a possible side effect of taking antipsychotic medications. However, the increased risk of gaining weight is more common with the use of second-generation or newer atypical antipsychotics.

It’s important to note, however, that everyone responds differently to these drugs. That said, weight changes may vary for each individual.

When researchers took interest in the likelihood of antipsychotics to cause weight gain, several subsequent studies have been published to confirm these findings. And ever since the potential of antipsychotics to cause weight gain in patients, researchers have been trying to find ways to reverse this side effect.

And in fighting antipsychotic weight gain, the diabetes drug metformin is the most widely studied medication. There’s also mounting evidence that metformin when combined with lifestyle changes, can potentially reduce antipsychotic-related weight gain.

It’s important to note, however, that in making decisions for your own well-being, always consult your health care provider first. Before adding metformin to your medication for possible weight loss, contact your psychiatrist and discuss other antipsychotic drug options.

People taking antipsychotics can also talk to their doctors about weight gain and other potential side effects of their medications and alternatives for treatment. Patients must also be able to weigh the risks and potential adverse effects of stopping or switching to another medication against possible side effects, such as weight gain.

What You Can Do

Gaining extra weight from your medications can be frustrating. It may be challenging to deal with, but the good news is it may be manageable.

A 2018 study found that practicing a healthier lifestyle can have desirable effects on a person’s health regardless of whether they lose the extra weight as a result.

Possible lifestyle changes may include monitoring your diet, increasing physical activity, and limiting portion sizes, among others.

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