Plasma neuropeptide levels negatively correlate with executive functions in anorexia

Plasma neuropeptide levels negatively correlate with executive functions in anorexia

Researchers published in Scientific Reports a study that negatively correlates the concentration of orexin A (a neuropeptide) with the executive functions in anorexic patients.

"We have evaluated the association between the concentration of the neuropeptide orexin A from blood plasma and the neuropsychological faculties in adult women, and we have been able to establish a negative correlation, i.e. the more concentration of orexin, lesser the adequacy of executive functions in patients" comments the author. 102 adult women, 51 of them with anorexia nervosa participated in the study; the other half were healthy women. Male representatives have been excluded due to the low prevalence of men in this disorder.

In patients with anorexia, there are usually changes in decision making, difficulties in adapting to new situations (inflexibility) and to see the general context of what they observe (excessive fixation in details), high rigidity and perfectionism and, in some cases, high levels of impulsivity.

Orexins, also called hypocretins, are neuropeptides (substances of the nervous system) used by neurons to communicate with each other. In previous studies it has been observed that orexins are involved in a variety of mechanisms, such as food intake and cognition, sleep disorders, among others.

Set-shifting was assessed using the Wisconsin Card Sorting Test (WCST), whereas decision making was measured using the Iowa Gambling Task (IGT). The anorexia group exhibited lower plasma OXA levels than the HC group. Lower mean scores were obtained on the IGT in AN patients. WCST perseverative errors were significantly higher in the AN group compared to HC. In both the AN and HC group, OXA levels were negatively correlated with WCST non-perseverative errors. Reduced plasma OXA concentrations were found to be associated with set-shifting impairments in anorexia.

One of the main objectives of the research group is studying the interaction between biological, cognitive and clinical factors. To achieve this, they are looking for neurobiological markers that can explain cognitive processes and those of diseases (such as anorexia, bulimia or obesity) and behavioral addictions. "That's why we wanted to study whether orexin A could play an important role in psychiatric disorders such as anorexia," justifies the author.

Once patients with anorexia have recovered, the decision-making levels are also more appropriate, meaning that they are reversible. For this reason, it would be of great interest to explore if the improvement of decision-making observed during the recovery of anorexia is related to changes in levels of orexin A. This way, we could assure a biomarker with potential clinical applications.