Cognition and Mental Health

A field of great interest and challenging methodology: self-reports vary, the expectancy effect is significant, and long-term data are almost entirely lacking.

1. Which Substances Have Been Studied in This Context

The overview shows how many studies exist per substance and type of investigation. A single study may be assigned to multiple topics—therefore, the numbers are not additive but instead describe this specific subset.

2. All Substances and Therapies with Controlled Studies on Cognition and Mental Health

100 substance and therapy pages assign controlled human studies to this area. The number comes from each page; one study can belong to several areas.

3. The Most Robust Studies

Ranked by evidential strength, not by popularity.

Controlled Human Study

• 1 A prospective, randomised double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha (2012)
• 2 Neuropharmacological review of the nootropic herb Bacopa monnieri (2013)
• 3 An investigation into the stress-relieving and pharmacological actions of an ashwagandha (Withania somnifera) extract: a randomised, double-blind, placebo-controlled trial (2019)
• 4 Clinical Use of Curcumin in Depression: A Meta-Analysis (2017)
• 5 Dietary Supplementation with Curcumin Reduces Circulating Levels of Glycogen Synthase Kinase-3β and Islet Amyloid Polypeptide in Adults at High Risk (2020)
• 6 Does Bacopa monnieri improve memory performance in older persons? Results of a randomised, placebo-controlled, double-blind trial (2010)
• 7 Adaptogenic and Anxiolytic Effects of Ashwagandha Root Extract in Healthy Adults: A Double-Blind, Randomised, Placebo-Controlled Clinical Study (2019)
• 8 Vitamin D Supplementation Improves Cognitive Function Through Reducing Oxidative Stress Regulated by Telomere Length in Older Adults with Mild Cognitive Impairment (2020)
• 9 Body Weight Management in Adults Under Chronic Stress Through Treatment With Ashwagandha Root Extract: A Double-Blind, Randomised, Placebo-Controlled Trial (2017)
• 10 The cognitive-enhancing effects of Bacopa monnieri: a systematic review of randomised, controlled human clinical trials (2012)
• 11 Meta-analysis of randomised controlled trials on cognitive effects of Bacopa monnieri extract (2014)
• 12 Curcumin Supplementation and Human Disease: A Scoping Review of Clinical Trials (2023)
• 13 Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers (2013)
• 14 Safety and clinical effectiveness of Withania somnifera (Linn.) Dunal root in human ailments (2020)
• 15 Efficacy and Safety of Ashwagandha (Withania somnifera) Root Extract in Insomnia and Anxiety: A Double-Blind, Randomised, Placebo-Controlled Study (2019)
• 16 Rhodiola rosea versus sertraline for major depressive disorder: A randomised placebo-controlled trial (2015)
• 17 Rhodiola rosea L. as a putative botanical antidepressant (2016)
• 18 Effects of 12-Week Bacopa monnieri Consumption on Attention, Cognitive Processing, Working Memory, and Functions of Both Cholinergic and Monoaminergic Systems (2012)
• 19 Further Evidence of Benefits to Mood and Working Memory from Lipidated Curcumin in Healthy Older People: A 12-Week, Double-Blind, Randomised, Placebo-Controlled Study (2020)
• 20 Efficacy and Safety of Ashwagandha Root Extract on Cognitive Functions in Healthy, Stressed Adults: A Randomised, Double-Blind, Placebo-Controlled Study (2021)