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. The bone lead levels measured were at or below the level of concern set by the US Centers for Disease Control.
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.