L-theanine augmentation of antipsychotic therapy can ameliorate positive, activation, and anxiety symptoms in schizophrenia and schizoaffective disorder patients.
This is not surprising. It seems that L-theanine is clinically useful in the exact ways one would expect.
The mean percentage removal of stains for test group was significantly higher than control group.
Note that this was a two week study. It's hard to guess whether greater benefit would occur over longer periods.
The addition of supraphysiologic doses of L-T4 (300 mcg per day) to an otherwise stable medication regimen of standard treatments resulted in a significant decline in depression scores during the 6-week, double-blind treatment phase. At endpoint (week 6), the mean HamD score showed a group difference of 3.7 points in favor of L-T4. Such difference is generally considered to be clinically meaningful in a short-term treatment trial for major depression. NICE used a 3.0-point difference in HamD change scores as a criterion of clinical significance.27
This is consistent with the open label data. The dose is also similar. Combining this placebo-controlled trial with the three open-label supraphysiological thyroxine studies that I've seen, that is sufficient for me to conclude efficacy. Namely, combining with Pfeiffer et al (350 mcg), Rudas et al (235 mcg) and Bauer et al (482 mcg)
I would like to see if this study mentions nonresponders. Those three other studies found roughly a 50% response rate. Thus, the effect size in responders may be twice as significant.