In addition, there is some evidence to support the involvement of genetic variants in catechol-o-methyl transferase and brain-derived neurotrophic factor in the aetiology of bipolar affective disorder.
Previous genetic studies investigating a possible involvement of variations at the brain derived neurotrophic factor (BDNF) gene locus in major depressive disorder (MDD), bipolar affective disorder (BPAD), and schizophrenia have provided inconsistent results.
A functional polymorphism Val66Met of BDNF gene was studied in patients with schizophrenia (n=336), bipolar affective disorder (n=352) and healthy controls (n=375).