Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in Cognitively Healthy Subjects: Implications for Alzheimer’s Dementia

Table 2

Zembrin extract effect on HAM-D in healthy control subjects.

	Average HAM-D	SD	value; 1-tailed	Effect size: % change
Before Zembrin ()	1.67	1.9		26.9%; decrease on HAM-D
After Zembrin ()	1.22	1.9
Before placebo ()	1.95	2.1		13.8%; decrease on HAM-D
After placebo ()	1.68	1.5