(Reuters Health) - Obese teens who have weight loss surgery are likely to lose the same amount of weight regardless of whether they were previously diagnosed with psychiatric problems, a U.S. study suggests.

Doctors used to consider people with mood or cognitive disorders poor candidates for so-called bariatric surgery because they were concerned these patients might not follow strict dietary rules afterward. Even though this is no longer an automatic reason to reject people for surgery, very little research has looked at outcomes for obese teens with mental health problems, researchers note in JAMA Pediatrics.

For the current study, researchers examined weight loss outcomes for 222 teens who had psychological evaluations before an operation known as sleeve gastrectomy, which reduces the stomach to the size of a banana. Based on the evaluations, one or more psychiatric disorders - including depressive or anxiety disorders, eating disorders or attention deficit hyperactivity disorder (ADHD) - was diagnosed in 71 percent of teens in the study.

Among the 169 teens who had bariatric surgery, there was no meaningful difference in weight loss after one year between those with a mental health diagnosis and those without one, the study found.

“We can say with more certainty that, regardless of demographic or socioeconomic background, having a psychiatric diagnosis of any type before you have sleeve gastrectomy does not seem to make the treatment any more or less effective,” said lead study author Eleanor Mackey of Children’s National Health System in Washington, D.C.

“For any adolescent with severe obesity, no matter where they come from or where they live, mental health is still important, but can be assessed and treated in conjunction with the surgery,” Mackey said by email.

At the start of the study, participants were 16 years old on average and severely obese.

About one in four had been diagnosed with anxiety, more than one in three had depression, and roughly one in five had ADHD. Eight percent had been diagnosed with an eating disorder.

One-third of the teens had at least two mental health diagnoses. Most often, when they had multiple issues, they had a combination of anxiety and depression.

There was no meaningful difference in mental health profiles for the teens who had bariatric surgery and those who did not.

To measure the success of weight loss efforts after surgery, researchers examined changes in body mass index (BMI), a measure of weight relative to height, to see how close teens came to a healthy BMI of 25 within one year of their operations.

Before surgery, teens in this group had an average BMI of 50.6, or what researchers described as excess BMI of 25.6, which is the amount of reduction necessary to achieve a healthy weight.

One year after surgery, teens lost an average of 55 percent of the excess weight they would need to shed to reach a BMI of 25. The magnitude of weight loss wasn’t influenced by any psychiatric diagnoses before surgery.

A limitation of the study, however, is that many teens dropped out before it ended, leaving one-year weight loss data for just 78 bariatric surgery patients. The study also wasn’t a controlled experiment designed to prove whether or how any psychological issues might directly impact weight loss.

It’s also possible that the study wasn’t long enough to get a complete picture of the connection between mental illness and bariatric surgery outcomes, said Dr. Geltrude Mingrone, a researcher at Catholic University in Rome who wasn’t involved in the study.

“One year of follow-up, in particular in adolescents, is a rather short time since we know that even in adults there is an important weight regain after five years,” Mingrone said by email. “We don’t know how this weight regain would influence the mental illness of these young patients.”

SOURCE: bit.ly/2swLoMY Pediatrics, online June 1, 2018.