Table 5. Comparison of Mean Symptom Reduction and Effect Size Across Four Classes of Antidepressants (Tricyclics, SSRIs, SNRIs, Atypicals) and a Novel Mechanism Antidepressant (Glutamate Antagonist).

		Mean Sx Reduction with Placebo		Mean Sx Reduction with Antidepressant		Mean Drug-Placebo Difference in Sx Reduction		Mean Effect Size
Tricyclics [19 trials, 19 tx arms]		29.0%		41.2%		12.1%		---a
SSRIs [38 trials, 52 tx arms]		31.6%		42.8%		10.9%		0.31
SNRIs [29 trials, 41 tx arms]		34.3%		46.6%		12.2%		0.31
Atypicals [19 trials, 22 tx arms]		33.8%		42.1%		7.7%		0.23
Glutamate (NMDA receptor) antagonist [1 trial, 1 tx arm]		42.4%		53.5%		11.1%		0.29
ANOVA		---b		p = 0.07c		p = 0.18c		p = 0.281d

^aeffect size could not be calculated for these data due to lack of sufficient details such as p-values or standard error

^bANOVA test could not be run to compare the values above due to duplication of placebo values between trials.

^ctest evaluates differences between data from Tricyclics, SSRIs, SNRIs, and Atypicals

^dtest evaluates differences between data from SSRIs, SNRIs, and Atypicals.