Non-coding genetic variation shaping mental health

Over 98% of our genome is non-coding and is now recognised to have a major role in orchestrating the tissue specific and stimulus inducible gene expression pattern which underpins our wellbeing and mental health. The non-coding genome responds functionally to our environment at all levels, encompassing the span from psychological to physiological challenge. The gene expression pattern, termed the transcriptome, ultimately gives us our neurochemistry. Therefore a major modulator of mental wellbeing is how our genes are regulated in response to life experiences. Superimposed on the aforementioned non-coding DNA framework is a vast body of genetic variation in the elements that control response to challenges. These differences, termed polymorphisms, allow for a differential response from a specific DNA element to the same challenge thus potentially allowing ‘individuality’ in the modulation of our transcriptome. This review will focus on a fundamental mechanism defining our psychological and psychiatric wellbeing, namely how genetic variation can be correlated with differential gene expression in response to specific challenges, thus resulting in altered neurochemistry which consequently may shape behaviour.