In one study, the researchers analyzed genetic data and results from neurocognitive tests for more than a quarter of a million people. They identified 939 genes related to intelligence that had not been implicated before. Furthermore, these genes were highly expressed in regions of the brain important for learning and cognition and were connected to genetic pathways involved in nervous system development and the structure of synapses.
According to Science, people with higher intelligence and longer lifespans were protected from Alzheimer’s disease, ADHD, or schizophrenia, the study found.
In the other study, the group carried out a meta-analysis of earlier research, looking at close to half a million people, and identified 599 genes implicated in neurotic behavior. While some of the genes appeared to be related to depression, others seemed to be coupled with anxiety—both traits of neuroticism. The investigators also found these genes were expressed in particular regions and cell types in the brain.