By Lisa Rapaport

(Reuters Health) – Even overweight and obese people who take certain psychiatric drugs associated with weight gain may be able to shed excess pounds by focusing on healthy eating and exercise habits, a recent study suggests.

Researchers followed 17,519 obese and overweight adults enrolled in a weight loss program focused on lifestyle changes at Wharton Medical Clinic in Ontario, Canada. Nearly one quarter of patients were taking at least one antidepressant or antipsychotic medication, some of which have weight gain as a side effect.

Overall, patients lost an average of 3.4 kilograms (7.5 pounds) over an average of 15.8 months of regular checkups at the clinic.

Women lost 3.1 kg when they didn’t take antidepressants or antipsychotics, similar to the 2.6 to 3.1 kg they lost when they took one or both types of medicine. Men lost 4.3 kg when they didn’t take psychiatric medicines, compared with 3.4 to 5.3 kg when they took one or both drugs.

“Contrary to what we thought, patients who are taking psychiatric medication can lose just as much weight as those who have not been prescribed these types of medication, even if they are known to cause significant weight gain,” said Rebecca Christensen, senior author of the study and a researcher at the Dalla Lana School of Public Health at the University of Toronto.

People with mental health disorders are more likely to be obese than other individuals, researchers note in the journal Obesity. While it’s unclear how much of this risk for excess weight might be caused by medications to treat the psychiatric conditions, several antidepressants and most antipsychotics are associated with significant weight gain, the study team notes.

At the start of the current study, all of the patients were either obese or overweight with at least one chronic health problem related to obesity. They all had regular checkups and ongoing support at a weight loss clinic with physicians, weight loss educators, counselors and dieticians.

Both men and women taking psychiatric medications in the study lost similar amounts of weight regardless of whether their particular drug was known to cause weight gain.

The researchers lacked data on any specific mental health diagnoses patients had or the exact doses or duration of use for any psychiatric medications.

Still, the results suggest that people with mental health disorders who need medication shouldn’t be dissuaded from taking their prescriptions just because they’re overweight or obese, said Dr. Anne McTiernan of the Fred Hutchinson Cancer Research Center and the University of Washington in Seattle.

“It looks like the same things that help any person lose weight work well in those taking antidepressant or antipsychotic medications: making lifestyle changes for reducing calories, engaging in physical activity, and meeting regularly with weight loss specialists,” McTiernan, who wasn’t involved in the study, said by email.

SOURCE: Obesity, online August 23, 2019.