S74 Clinical neuropsychopharmacology

P.3.023 Prebiotic intake reduces the waking

cortisol response and alters emotional

bias in healthy volunteers

K. Schmidt1 °, P. Cowen1, C.J. Harmer1, G. Tzortzis2,P.W.J. Burnet1. 1University of Oxford, Departmentof Psychiatry, Oxford, United Kingdom; 2Clasado Ltd,Clasado Research Services Ltd, Reading, United Kingdom

Background: There is now compelling evidence fora link between gut microbiota and brain function inboth rodents and humans [1]. A recent fMRI studyextended these findings to show that ingestion of probiotics(strains of gut bacteria that confer a beneficial effecton their host) can modulate the neural correlates ofemotional processing [2], and abnormalities in theprocessing of emotional information are strongly linkedto psychiatric disorders such as anxiety and depression.Further, the hypothalamic–pituitary–adrenal (HPA) axis,often dysregulated in patients with (and those at riskof) depression and anxiety, impacts affective and memoryprocessing and has strong bidirectional links with the gutmicrobiome [3]. The present study explored the effectsof prebiotics − nutrients that proliferate several intrinsicgut microbiota in the host − on HPA axis activity andemotional processing in healthy volunteers.

Methods: Forty-five healthy volunteers (22 males) re-ceived one of two prebiotics (fructooligosaccharides [FOS]or Bimuno-galactooligosaccharides [B-GOS]) or a placebofor 3 weeks. The salivary cortisol awakening re-sponse (CAR) was sampled before and after prebiotic/placebo administration to assess HPA axis activity. Onthe final day of treatment participants completed acomputerised task battery assessing the processing ofemotionally salient information.

Results: The salivary CAR did not differ significantlybetween groups at baseline but was significantly lowerafter B-GOS compared with placebo (day × group ×time ANOVA, day × group interaction [F(2,41) = 3.61,p< 0.05] followed-up with group × time ANOVAs [maineffects of group: baseline: F(2,41) = 1.08, n.s., post:F(2,41) = 4.20, p< 0.05; Placebo vs. GOS p< 0.05, allothers p> 0.40]). Analysis of behavioural data revealeddecreased attentional vigilance to negative versus positiveinformation in a dot-probe task after B-GOS comparedto placebo (group × emotion × masking condition[F(2,41) = 3.14, p = 0.05] follow-up ANOVAs [valence ×group interaction: masked: F(2,41) = 0.85, n.s.; unmasked:F(2,41) = 4.29, p< 0.05, Placebo vs. GOS p< 0.05,all others n.s.]).

Conclusions: Our study demonstrates that the manip-ulation of gut microbiota with B-GOS alters HPA axisresponsivity in healthy volunteers, which is in keeping with

the effects of probiotics. In rodents, the gut microbiomehas an important role in regulating the HPA axis earlyin life, however, as of yet much less is known fromhuman populations. B-GOS was also shown to increasethe processing of positive versus negative attentionalvigilance compared to placebo, which supports findingsthat the modulation of gut microbiota with probiotics hassubjective anxiolytic effects since attentional vigilance isbelieved to play a key role in anxiety and its modulationby anxiolytics. No effects were found after administrationof a FOS prebiotic. Overall, novel evidence supportsthe notion that manipulations of gut microbiota showwidespread effects on central functioning and behaviouralphenotypes via the HPA axis, as well as the vagus nerve,serotonergic system, and immune system [1]. While theexact mechanisms of action of pre- and probiotics inhealthy and clinical populations and their relation to theprocessing of emotional information are still relativelypoorly defined, our study supports their role in affectiveinformation processing and the regulation of the HPA axis.

Reference(s)

[1] Cryan, J.F., Dinan, T.G., 2012. Mind-altering micro-organisms: the impact of the gut microbiota on brainand behaviour. Nature Reviews Neuroscience 13, 701–712.

[2] Tilisch, K., Labus, J., Kilpatrick, L., Jiang, Z.,Stains, J., Ebrat, B., Guyonnet, D., Legrain-Raspaud, S., Trotin, B., Naliboff, B., Mayer, E.A.,2013. Consumption of fermented milk product withprobiotic modulates brain activity. Gastroenterology144(7), 1394–1401.

[3] Dinan, T.G., Cryan, J.F. 2012. Regulation of thestress response by the gut microbiota: implications forpsychoneuroendocrinology. Psychoneuroendocrinol-ogy 37(9), 1369–1378.

P.3.024 Face and emotion recognition in children

with ADHD and autism spectrum

disorders: Effects of methylphenidate

F. Placini1 °, C. Peddis1, S. Carucci1, S. Petza1,C. Balia1, J.A. Sergeant2, A. Zuddas1. 1Universityof Cagliari, Biomedical Science Centre forPharmacological Therapies in Child & AdolescentNeuropsychiatry, Cagliari, Italy; 2Vrije Universiteit,Clinical Neuropsychology, Amsterdam, The Netherlands

Objective: The object of this study was to compareAutism Spectrum Disorders (ASD), Attention DeficitHyperactivity Disorder (ADHD) and Typically DevelopingChildren (TDC) while processing facial emotions and