Enhancing Panic and Smoking Reduction Treatment With D-Cycloserine

Inclusion Criteria: * Male and female patients ages 18-65 capable of providing informed consent * Willing and able to provide informed consent, attend all study visits and comply with the protocol * Daily smoker for at least one year * Currently smoke an average of at least 8 cigarettes per day * Report a motivation to quit smoking in the next month of at least 5 on a 10-point scale * Evidence of panic attack within the past year and endorsement of smoking as an emotion regulation strategy (i.e., score at least a 78 on the SAEQ). Exclusion Criteria: * Subjects who do not use smoking as an emotion regulation strategy * Current diagnosis of a psychotic, eating, developmental or bipolar disorder * Significant suicide risk as determined by structured interview * Pregnant women, lactating women, and women of childbearing potential who are not using medically accepted forms of contraception (e.g., IUD, oral contraceptives, barrier devices, condoms and foam, or implanted progesterone rods stabilized for at least 3 months). * Psychoactive substance abuse or dependence (excluding nicotine dependence) within the past 6 months * Current use of isoniazid or ethionamide compounds * A history of significant medical condition and/or be deemed as currently unhealthy in the context of a complete physical examination * Limited mental competency and the inability to give informed, voluntary, written consent to participate * Current use of any pharmacotherapy or psychotherapy for smoking cessation not provided by the researchers during the quit attempt * Concurrent psychotherapy initiated within three months of baseline, or ongoing psychotherapy of any duration directed specifically toward treatment of anxiety or mood disorder other than general supportive therapy initiated at least 3 months prior to the study * Use of other tobacco products * Plans to move outside of the immediate area in the next six months * Insufficient command of the English language