79 to find a large effect size, f = 0.40, for the main effects sellekchem and the interaction between menstrual phase and depressive symptoms. The p values less than .05 were deemed statistically significant. No adjustments for multiple comparisons were made. SAS V9.1.3 (SAS Institute, Cary, NC) was used for the statistical analyses. RESULTS Study Sample A total of 52 participants completed the full protocol; however, three participants were excluded from the analysis due to serum hormone levels inconsistent with assigned menstrual phase and two were excluded for not remaining abstinent from nicotine based on serum nicotine samples. Therefore, the final sample includes 47 participants. There were no significant differences in demographics, smoking behavior, cardiovascular variables, or hormone levels by stratification or randomization (Table 1).

Overall, correlations between serum nicotine, heart rate, and diastolic blood pressure indicate a dose-related physiological response to nicotine was achieved (Table 2). No significant differences were found for sequence or time effects (data not shown). Table 1. Demographics and Baseline Characteristics by Stratification and Randomization (n = 47)a Table 2. Serum Nicotine Concentrations and Cardiovascular Response by Depressive Symptoms Group and Menstrual Phase (n = 47) Physiological Response to Nicotine by Menstrual Phase There were no statistically significant differences in serum nicotine values, blood pressure, heart rate, or affect by menstrual phase. However, two trends were noted suggesting that F phase may be associated with higher Cmax nicotine (p = .

0553) and heart rate at Cmax (p = .0749; Table 2). Physiological Response to Nicotine by Depressive Symptoms Group There were no significant differences in serum nicotine values, heart rate, blood pressure, or affect by depressive symptoms group (Table 2). Physiological Response to Nicotine by Menstrual Phase and Depressive Symptoms The women in the NDS group had significant menstrual phase differences in their physiological response to nicotine, such that Cmax, heart rate, and diastolic blood pressure were all significantly higher in the F phase compared with the L phase; whereas those in the DS group did not have a significant AV-951 menstrual phase difference in their physiological response to nicotine (Table 2; Figure 1). A similar relationship was seen in the negative association between nicotine Cmax and progesterone, which was significant in the NDS group (b = ?0.13, p < .001), but not in the DS group (b = ?0.00, p = .929). Significant associations were also noted between progesterone and heart rate in the NDS group (b = ?0.33, p = .014) and between progesterone and diastolic blood pressure in the DS group (b = 0.39, p = .010).