Life-long, low-level lead exposure is associated with increased reports of depression and anxiety that are related to phobias in older women, according to research published in Environmental Health Perspectives.
It may be worth mentioning that the hair metal concentration reflects the bone metal concentration. (Thomas L. Labor & Diagnose, Med. Verlag Marburg 1992, pg 430)
Another recent study links lead exposure to pessimism in men.
December 2009, JAMA Psychiatry
Higher blood lead levels were associated with increased odds of major depression and panic disorders. Exposure to lead at levels generally considered safe could result in adverse mental health outcomes.