Patients being treated for obesity who show poor "focus" during treatment more often fail to lose weight or maintain reduced weight, according to researchers from the Behavioral Medical Center for Treatment and Research in Portland, Oregon.

An evaluation of these patients found a number of them suffering from attention deficit/hyperactivity disorder (ADHD), a factor suspected of hindering successful weight control.

Researchers reviewed the clinical records of 215 patients undergoing treatment for obesity during the year 2000. Data collected and analyzed included age, sex, beginning and ending body mass index, number of clinic visits, months of treatment and diagnostic category (ADHD, some ADHD symptoms, non-ADHD).

"ADHD was highly prevalent among obese patients and highest in those with extreme obesity," wrote the authors in the journal BMC Psychiatry. "Patients who were both obese and had ADHD were less successful in their weight loss treatment compared to those without ADHD."

Researchers are not sure why obese people tend to have ADHD but speculate it may involve brain dopamine or insulin receptor activity.

"If replicated in further studies, these findings have important implications for treatment of severe and extreme obesity," wrote the researchers.

Other sources: BMC Psychiatry