Mental and neurological disorders seem like such a modern thing.
Think about it: The Diagnostic and Statistical Manual of Mental Disorders was only published in 1952, just over 65 years ago. According to Wikipedia, "the beginning of psychiatry as a medical specialty is dated to the middle of the nineteenth century." Though ancient texts (dating back to the 3rd Century BCE) dealt with mental disorders, it's only in the last few centuries that they have been seriously approached from a scientific standpoint.
However, research out of the National Institute of Mental Health may have traced mental disorders back to our prehistoric past. Specifically, the parts of our brains that often are affected by mental disorders may carry genetic traces of Neanderthal brains.
The parts of our brain responsible for visualization, object location, and the use of tools may be partyl derived from Neanderthal gene variants. We still have those same gene variants that our prehistoric ancestors did. According to new MRI scans, that genetic variation may play a role in mental disorders. By studying those parts of the brains, scientists may be able to better understand autism-related disorders and schizophrenia, among others.
According to the Science Daily article:
"It's been proposed that Neanderthals depended on visual-spatial abilities and toolmaking, for survival, more so than on the social affiliation and group activities that typify the success of modern humans -- and that Neanderthal brains evolved to preferentially support these visuospatial functions. Now we have direct neuroimaging evidence that such trade-offs may still be operative in our brains."
The genes we share with ancient Neanderthals may impact the development of certain parts of our brains, including the parts that are affected by autism-related disorders, schizophrenia, and other mental disorders.