Kava for Anxiety
Kava shows a genuine but inconsistent anti-anxiety signal, yet because it has caused severe liver injury and the largest modern trial found no benefit, it is not recommended for treating anxiety.
Why this grade7-layer evidence engine
The efficacy evidence is real but heterogeneous, which is why this lands at a preliminary (B) grade rather than higher. Two Cochrane systematic reviews favored kava over placebo on the Hamilton Anxiety Scale (PMID 11687196, WMD 9.69; PMID 12535473, WMD 5.0 points, p=0.01), and a small randomized trial reported a medium effect (PMID 23635869, d=0.63, p=0.046).
Crucially, the largest, longest, government-funded randomized trial (PMID 31813230, n=171, 16 weeks) was negative on its primary endpoint (p=0.25) and actually saw more liver-enzyme abnormalities with kava. A 2018 systematic review (PMID 30396607) likewise found a positive pooled result (RR 1.50) driven by only 3 of 7 trials, so the benefit is inconsistent and the older positive estimates may be inflated.
Safety, not efficacy, is the deciding factor. The FDA, WHO, NIH/NCCIH, Mayo Clinic, and Cleveland Clinic all warn that kava has been linked to severe, sometimes fatal liver damage, and the UK and Germany prohibited kava medicines outright after hepatotoxicity reports. The ADAA/APA acknowledge kava as one of the better-studied anxiety herbs yet explicitly do not recommend it. Bottom line: any modest benefit does not justify the liver-injury risk.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.726
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — A 級條件未達 (需 E1-E3 + L5≥2 supportive + L4 無 against；實際 E1 / L5=1 / L4_against=0)
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status