Psychiatric and neurological diseases continue to be a massive global health burden: The World Health Organization estimated that in 2019, globally 280 million individuals were affected by depression, 39.5 million by bipolar disorder and 287.4 million by schizophrenia (SCZ)1 . Similarly, the number of people living with dementia is expected to rise from 50 million today to 152 million by 2050 (ref. 2), with similar trajectories for other neurodegenerative diseases. Although substantial progress has been made in uncovering the genetic basis of these diseases through genome-wide association studies (GWAS), much of how the identified genetic variants impact brain function remains unknown.
