This study will evaluate the potential therapeutic value of two neurosteroid treatments (DHEA and pregnenolone) in the treatment of tobacco withdrawal symptoms. This will include assessing whether these agents relieve craving for cigarettes elicited by exposure to a mildly stressful cognitive task. Pregnenolone (400 mg orally), DHEA (400 mg orally) and placebo will be administered one at each of the three sessions in a randomized order.

Inclusion Criteria:

1. male;
2. 18-65 years old;
3. smoked an average of at least 10 cigarettes per day for three cumulative or continuous years of a brand that delivers (by Federal Trade Commission rated yields) at least 0.5 mg nicotine;
4. afternoon expired carbon monoxide reading of at least 10 ppm;
5. in general good health, based on physical examination, EKG serum chemistries, CBC and urinalysis.

Exclusion Criteria:

1. Participants must not have uncontrolled hypertension (systolic >140 mm Hg, diastolic >95 mm Hg)
2. hypotension (systolic <90 mm Hg, diastolic <60 mm Hg);
3. coronary heart disease;
4. heart attack;
5. cardiac rhythm disorder (irregular heart rhythm);
6. chest pains (unless history, exam, and EKG clearly indicate a non-cardiac source);
7. cardiac (heart) disorder (including but not limited to valvular heart disease, heart murmur, heart failure);
8. liver or kidney disorder (except kidney stones, gallstones);
9. gastrointestinal problems or disease other than gastroesophageal reflux,
10. heartburn, or irritable bowel syndrome;
11. ulcers within the past 6 months;
12. lung disorder (including but not limited to COPD, emphysema, and asthma);
13. brain abnormality (including but not limited to, stroke, brain tumor, seizure disorder);
14. history of fainting;
15. problems giving blood samples;
16. diabetes;
17. current cancer or treatment for cancer in the past 6 months (except basal or squamous cell skin cancer);
18. other major medical condition;
19. major depression, panic disorder, anxiety, bipolar disorder, schizophrenia, risk of suicide, or substance dependence other than nicotine dependence;
20. subjects who endorse suicidal ideation on the MINI abridged;
21. alcohol or drugs abuse;
22. reported use of illicit drugs within the past 30 days, or if the drug screen is positive;
23. reported use of smokeless tobacco (chewing tobacco, snuff), cigars, pipes, or nicotine replacement therapy; testosterone replacement therapy, DHEA or Pregnenolone; experimental (investigational) drugs; psychiatric medications (including antidepressants, anti-anxiety agents. anti-psychotics), sleep aids, medications that increase DHEA and/or DHEA-S concentrations (including, but not limited to: diltiazem, benfluorex, amlodipine, alprazolam, danazol, metformin, nitrendipine and retinol), or any other medications that are known to affect smoking (e.g. clonidine, muscle relaxants, opiate pain medications) within the past 2 weeks.