CANTAB (Cambridge Neuropsychological Test Automated Battery)

Valérie Dormal et al. (2025) · Nutrients

This randomized, double-blind, placebo-controlled trial with 149 adults explored whether a specially grown red Panax ginseng root powder changes perceived stress, mood and thinking speed. Perceived stress is a person's own sense that demands outweigh their ability to cope, and it is tied to anxiety, depression, heart disease and weaker cognition. Panax ginseng, also called Asian or Korean ginseng, is a root used as an adaptogen, meaning a substance proposed to help the body handle stress. Steaming the root turns its common ginsenosides (the main active compounds) into rare ginsenosides, which the authors describe as absorbed better and more pharmacologically active. The volunteers were adults aged 18 to 60 in Belgium with moderate stress scores on the Perceived Stress Scale. For 21 days, 72 took a daily 200 mg capsule of the ginseng powder, which supplied 22.4 mg of ginsenosides, and 77 took a look-alike placebo made of rice flour and brown sugar. Before and after, everyone completed stress, depression and mood questionnaires and two computer-based Cambridge Neuropsychological Test Automated Battery (CANTAB) tasks of visual memory and spatial planning. Stress scores dropped in both groups, but the drop was larger with ginseng (4.3 points versus 2.7 points on the scale; p = 0.040, meaning the gap is unlikely to be chance). Negative mood fell only in the ginseng group (2.6 points; difference between groups p = 0.032). Depression scores improved in both groups, and the extra improvement with ginseng did not reach significance (p = 0.073). On the planning task, ginseng users took about 1.6 seconds less to make a first choice (p = 0.002 within the group; p = 0.036 against placebo). Memory-task errors fell only in the ginseng group, yet the groups did not differ significantly, and the number of planning problems solved correctly on the first try was similar in both. No serious adverse events occurred, mild and moderate events were not significantly different between groups, and compliance was above 97% in both groups. Seven volunteers dropped out, five of them from the placebo group. The authors describe the benefits as moderate and view ginseng as a complement to broader treatment rather than a stand-alone approach. Limits include the short three-week period, volunteers who were stressed but not clinically unwell, sizable improvement in the placebo group, and many outcomes tested without a described correction. Long-term safety and effects in people with higher stress, anxiety or depression remain unstudied, and the results apply to this one proprietary preparation tested in a single trial.