L-Theanine for Panic Disorder

L-theanine takes the edge off general nervousness in small trials, but it has never been tested in panic disorder and does nothing about the catastrophic misinterpretation that maintains the condition.

L-theanine crosses the blood-brain barrier and modestly increases alpha-wave activity while dampening glutamatergic excitation, producing relaxation without sedation.

Trials of L-theanine are small, short, and conducted in healthy adults under acute stress or in generalised anxiety, where effect sizes on self-reported tension are modest. No randomised trial has examined panic disorder, panic attack frequency, or avoidance behaviour. Because panic disorder is maintained by the interpretation of bodily sensations rather than by baseline arousal, an agent that slightly lowers arousal would not be expected to alter the core mechanism. There is also a specific risk: taking a capsule at the onset of an attack functions as a safety behaviour, and safety behaviours are the main reason panic disorder persists.

People whose attacks are driven by catastrophic misinterpretation — which is most people with panic disorder — will see no change in attack frequency.