The highest incidence of mental/nerve diseases seen among Jews affects nearly all of them given their miniscule population.<quoted text>
It appears you are in error, exciting recent research indicates those defects actually affect the anti-semitic community, who are still in denial.
These diseased conditions of mind/nerves that we see among Jews are on account of rampant and continuing incest among the Jews for millennia.
However, the Muslims, too, show a high incidence of mental distortion and bodily illnesses on account of abnormal incestuous marriages but given their large numbers - 1.5 billions plus and growing - I think the abnormal genetic conditions due to incest is kind of lessened.
The only other community that manifests extremely high incidence of mental/nerve illnesses - in fact more than the Jews - is the minute Zoroastrian community which hardly numbers 100,000 or lesser.