The dietary intervention included a daily use, for a period of three months, of margarine enriched (Experimental group) or not (placebo group) with Omega-3 fatty acids. We hypothesized that this intervention will improve some cognitive deficits (such as attention, processing speed) and behavioural symptoms (e.g. depression, aggressiveness, impulsivity) together with an impact on brain structure (e.g. white-matter properties related to myelination).