Reversibility of serotonin irritation syndrome with atmospheric anions.

Clinical reports and animal studies support the existence of a "serotonin irritation syndrome." This is a putative anxiety state caused by a rise in atmospheric cations and reversed by a corresponding rise in anions. Volunteers were exposed to generated ambient cations and anions under controlled conditions. Cations were found to increase anxiety, excitement, and suspicion. Anions reversed the effects of cations and, in addition, reduced suspicion and excitement to levels below those occurring before cationization. Implications of these findings and the possible mediation of effects by serotonin are discussed.