Improvement in cognitive abilities following cabergoline treatment in patients with a prolactin-secreting pituitary adenoma Itziar Montalvo a , Marta Llorens a , Laia Caparrós a , Montserrat Pamias a , Jordi Torralbas a , Olga Giménez-Palop b , Assumpta Caixàs b , Diego J. Palao a and Javier Labad a Hyperprolactinaemia may affect sexual and reproductive functioning. However, recent studies suggest that increased prolactin levels may also have negative effects on cognition. We aimed to study whether the reduction in prolactin levels by cabergoline in patients with hyperprolactinaemia is followed by an improvement in cognitive tasks. We studied seven patients with hyperprolactinaemia caused by a prolactinoma that had an indication to start treatment with cabergoline. All patients were assessed twice (baseline and 6–12 months after cabergoline treatment) with a cognitive battery. Plasma prolactin levels were determined. We found a significant improvement in the speed of processing, working memory, visual learning and reasoning and problem-solving domains after cabergoline treatment. Improvements in speed of processing and reasoning and problem solving were greater in patients with baseline prolactin levels above the median. In summary, a reduction in prolactin levels by cabergoline in patients with hyperprolactinaemia is followed by an improvement in cognitive abilities. This finding suggests that prolactin may be involved in cognitive processes, although cabergoline could also have procognitive effects that are independent of prolactin changes. Further clinical trials are needed to confirm the potential cognitive-enhancement properties of cabergoline in patients with chronic hyperprolactinaemia. Int Clin Psychopharmacol 00:000–000 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. International Clinical Psychopharmacology 2017, 00:000–000 Keywords: cabergoline, cognition, dopamine agonist, prolactin, prolactinoma Departments of a Mental Health, CIBERSAM and b Endocrinology, Corporació Sanitària Parc Taulí, Sabadell, Spain Correspondence to Javier Labad, MD, PhD, Department of Mental Health, Parc Taulí Hospital Universitari, CIBERSAM, 08208 Sabadell, Spain Tel: +34 93 723 1010; fax: +34 93 723 7181; e-mail: jlabad@tauli.cat Received 16 June 2017 Accepted 17 August 2017 Introduction Amenorrhoea, galactorrhoea, sexual dysfunction and infertility are the most widely studied consequences of hyperprolactinaemia (Horseman and Gregerson, 2013). Recent studies in nonpsychiatric (Henry and Sherwin, 2011; Bala et al., 2016) and psychiatric populations (Montalvo et al., 2014), as well as in animal models (Torner et al. , 2013), suggest that hyperprolactinaemia may have a negative effect on cognitive abilities. However, no previous studies have explored whether the reduction in prolactin levels is followed by an improvement in cognitive tasks. Prolactinomas are adenomas of the pituitary gland that cause hyperprolactinaemia and require treatment with dopamine agonists (e.g. cabergoline) when prolactin- related symptoms appear. Although a recent study (Bala et al., 2016) carried out in patients with a prolactinoma suggests that overproduction of prolactin causes memory and attention impairments, no previous studies have explored whether the reduction in prolactin levels by dopamine agonists is followed by an improvement in cognitive tasks. Thus, the main aim of our study was to carry out a preliminary study to explore this issue. Patients and methods Patients We studied 10 patients who had hyperprolactinaemia caused by a prolactinoma and had received an indication to start treatment with cabergoline. All prolactinomas were microprolactinomas ( < 10 mm in diameter). Participants were recruited from the Endocrinology Department of Corporació Sanitària Parc Taulí (Sabadell, Spain). Exclusion criteria were mental illness, prolactin-elevating drugs, substance abuse or dependence, mental retardation, dementia, endocrinological disorder other than hyperprolactinaemia, autoimmune dis- eases and pregnancy. All patients provided written informed consent before starting the study. We had previously obtained study approval by the local ethics committee. All patients completed a baseline visit before starting cabergoline treatment. We aimed to follow-up with patients during a second visit 6–12 months after the baseline visit. Of the 10 patients, seven completed the follow-up visit and three patients did not complete the follow-up visit because of pregnancy, a change in the place of residence and the refusal to take cabergoline. Original article 1 0268-1315 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/YIC.0000000000000199 Copyright r 2017 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.