an overlap between schizophrenia and bipolar disorder. For example, relatives of patients with bipolar disorder have an increased risk of developing schizophrenia and vice versa (Valles et al., 2000; Cardno et al., 2002; Maier et al., 2002; Laursen et al., 2009; Lichtenstein et al., 2009; Van Snellenberg and de Candia, 2009).
