Genetic findings are challenging the symptom-based diagnostic classification system of mental disorders

The present diagnostic classification of mental illnesses is primarily based on symptomatology. A recent cross-disorder genome-wide association study revealed that there were genetic similarities between multiple clinically defined diagnoses (including schizophrenia, bipolar disorder, depression, attention deficit hyperactivity disorder, and autism spectrum disorder) on regions of chromosomes 3p21 and 10q24 and single-nucleotide polymorphisms (SNPs) within two L-type voltage-gated calcium channel subunits of CACNA1C and CACNB2. These findings suggest that the pathogenesis of these five independent disorders are related. Such cross-disorder genetic studies challenge the current symptom-based diagnostic classification of mental disorders. Researchers need to identify creative ways to bridge the gap between these two approaches to understanding and labelling mental disorders.