1 Introduction

Psychiatric disorders have a great impact on morbidity and mortality [1][2]. According to the World Health Organization (WHO), one of every four people will suffer mental or neurological disorders at some point in their lives [3]. It has been suggested that most psychiatric disorders display a strong genetic component [4][5][6]. During the last years there has been a growing research in psychiatric disorders’ genetics [7], and therefore the number of publications that focus on psychiatric disorders have increased steadily (Figure 1).