Prefrontal transcranial direct current stimulation (tDCS) is rising in popularity as a potential low-cost and easy-to-use treatment for neuropsychiatric conditions. However, effect sizes of prefrontal tDCS protocols are rather modest and a large heterogeneity in clinical effects is seen, which can be partly explained due to the variability of electric field (EF) strength in the brain owing to anatomical interindividual differences and by inter-experimental differences. It is proposed that prefrontal tDCS effects could benefit from personalised and optimised methodological approaches in order to increase its effects. A method that has been gaining attention in this area is the so-called EF simulation, which allows the evaluation of inter-individual EF strength produced by tDCS in the brain, as well as identify EF patterns of distinct tDCS montages. In view of this, the aim of this study is to investigate predictors of tDCS response based on inter-individual anatomical brain differences, and to unravel the optimal tDCS intensity and montage on the prefrontal cortex. By using EF simulations this work will investigate the variability of tDCS response via a) inter-individual differences (work package 1 (WP1); b) distinct tDCS protocols probing the PFC (WP2), and c) their impact on working memory performance of depressive patients. Advancements in this field are needed in order to shift the tDCS towards a more ‘‘precision-oriented’’ practice.