Emotional recognition training modifies neural response to emotional faces but does not improve mood in healthy volunteers with high levels of depressive symptoms

IMPORTANCEDepression is a debilitating and highly prevalent mental health disorder. There is a need for new, effective, and scalable treatments for depression, and cognitive bias modification (CBM) of negative emotional processing biases has been suggested as one possibility. Such treatments may form the basis of digital therapeutics, that could be administered remotely and at low cost, should they prove to be effective.\n\nOBJECTIVESStudy one was designed to determine neural correlates of a recently developed CBM technique for emotion recognition training; specifically, our aim was to compare the effects of training vs placebo on pre-specified regions of interest involved in emotion processing that are known to be sensitive to antidepressant treatment. Study two aimed to investigate efficacy of training on mood measures at 2 and 6-week follow-up and was powered to replicate and extend earlier findings.\n\nDESIGN, SETTING, AND PARTICIPANTSBoth studies were double blind RCTs, in which participants completed five sessions of emotion recognition training or sham training, in the laboratory, over a one-week period. In study one (N=37), following this training, participants completed a novel emotion recognition task whilst undergoing fMRI. In study two (N=190), measures of mood were assessed post training, and at 2-week and 6-week follow-up. Both studies recruited analogue samples of healthy volunteers with high levels of depressive symptoms (BDI-ii > 14).\n\nMAIN OUTCOMES AND MEASURESIn study one, our primary outcome was neural activation in the following pre-specified regions of interest: the bilateral amygdala, the mPFC, bilateral dlPFC, and the occipital cortex. In study two, our primary outcome was depressive symptoms over the last 2 weeks assessed using the BDI-ii at 6-week follow-up. Secondary outcomes included depressive symptoms measured using the HAM-D, and positive and negative affect assessed using the PANAS.\n\nRESULTSIn both studies, CBM resulted in a change in emotion recognition bias, which (in study two) persisted for 6 weeks after the end of the CBM phase. In study one, CBM resulted in increases neural activation to happy faces compared to sad faces, with this effect driven by an increase in neural activity for happy faces. We saw this increase in activation for this contrast at both the whole brain level and among our a priori ROIs, specifically the mPFC and bilateral amygdala. In study two, CBM did not lead to a reduction in depressive symptoms on the BDI-ii, or on related measures of mood, motivation and persistence, or depressive interpretation bias.\n\nCONCLUSIONS AND RELEVANCECBM of emotion recognition appears to have effects on neural activity that are similar in some respects to those induced by SSRI administration (study one), but we find no evidence that this has any effect on self-reported mood in an analogue sample of healthy volunteers with low mood (study two).