Table 1. Startle, Heart Rate, and Skin Conductance Level as a Function of Meclizine Dose (Days 2–4).

	Placebo	Low dose (12.5 mg)	High dose (25 mg)
Startle (μV)	6.82 (1.08)	5.61 (0.64)	6.77 (0.88)
Heart rate (bpm)				Startle trial effect (p<0.0002)
Overall mean	68.37 (2.08)	68.91 (2.27)	68.13 (1.92)
Pre-startle trial	68.17 (2.05)	68.68 (2.26)	67.89 (1.91)
Post-startle trial	68.67 (2.06)	69.33 (2.25)	68.46 (1.87)
Skin response (μS)				Startle trial effect (p<0.006)
Overall mean	2.37 (0.29)	2.22 (0.26)	2.49 (0.28)
Pre-startle trial	2.45 (0.31)	2.32 (0.28)	2.60 (0.29)
Post-startle trial	2.47 (0.31)	2.33 (0.28)	2.61 (0.30)

Data represent mean values (±SEM). Meclizine did not significantly affect the amplitude of the startle response, heart rate, or skin conductance level. Startle trials increased HR and GSR levels (as in baseline sessions), but these changes were not affected by either drug dose.