The exclusion of nicotine: closing the gap in addiction policy and practice.

Addiction is a complex brain disease with frequently overlapping expressions involving nicotine, alcohol, and other drugs. Yet current health care practices, public policies, and national treatment data too often exclude nicotine or address its use as completely separate from other forms of substance use and addiction, compromising patients' health and incurring unnecessary health care costs. Effective prevention and treatment requires the inclusion of nicotine in a comprehensive approach addressing all manifestations of addiction within health care policy and practice.