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Aim: The main aim of this study was to investigate the additional effects of L‐theanine, an amino acid in tea and an analog of glutamate with neuroprotective and anti‐depressant properties, on obsessive–compulsive disorder (OCD) symptoms in combination with fluvoxamine. Methods: Patients from either sex aged between 18 and 60 years diagnosed with OCD, based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐5), who had a Yale‐Brown Obsessive Compulsive Scale (Y‐BOCS) score of more than 21 were enrolled in a double‐blinded, parallel‐group, placebo‐controlled, clinical trial of 10 weeks to receive either L‐theanine (100 mg twice daily) and fluvoxamine (100 mg daily initially followed by 200 mg daily after week 5) or placebo and fluvoxamine. The primary outcome of interest in this study was the Y‐BOCS total score decrease from baseline. Results: From a total of 95 evaluated patients, 50 completed our study; 30 were randomly assigned to each group. Multivariate analysis (ANOVA) showed a significant effect of time ×$$ \times $$ treatment for L‐theanine in obsession subscale (F = 5.51, P = 0.008) of the Y‐BOCS score but not in the total and compulsion scores. Our results showed significantly more improvement in obsession subscale scores in L‐theanine compared to placebo group (P = 0.007, Cohen's d = 0.82). Also, total Y‐BOCS scores were lower in L‐theanine compared to placebo group at week 5 (P = 0.039, Cohen's d = 0.60) and 10 (P = 0.008, Cohen's d = 0.80). However, there was no significant between‐group differences in compulsion subscale scores. Complete response was also more frequent in the L‐theanine group (P = 0.0001). Conclusion: Findings in this study suggest L‐theanine as a relatively safe and effective adjuvant therapy for moderate to severe OCD. [ABSTRACT FROM AUTHOR]

To evaluate the effects of modafinil on neuropathic pain induced by sciatic nerve cuffing in mice, and possible contribution of nitrergic/inflammatory and serotonergic systems. Neuropathic pain was induced by applying a polyethylene cuff around the left sciatic nerve. Seven days later, mice received modafinil (50, 100, and 200 mg/kg; intraperitoneal [i.p.]) and morphine (10 mg/kg, i.p.) as control. Mice also received pretreatments of the nonselective nitric oxide (NO) synthase (NOS) inhibitor L-NAME, the selective neuronal NOS inhibitor 7-nitroindazole, the selective inducible NOS inhibitor aminoguanidine, and the selective serotonin reuptake inhibitor citalopram before modafinil (100 mg/kg). von Frey test was used to evaluate mechanical allodynia. Additionally, sciatic nerves were collected for histopathological analysis. Tissue levels of NO metabolites, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were assessed. Animals whose sciatic nerves were cuffed had a significantly (P<0.001) decreased paw withdrawal threshold (PWT) compared with the sham-operated group. Modafinil (100 mg/kg) and morphine significantly reversed PWT (P<0.001). Pretreatments with L-NAME, 7-nitroindazole, aminoguanidine, and citalopram in different groups markedly reversed analgesic effects of modafinil. Tissue homogenates of Cuffed sciatic nerves showed significantly higher levels of NO metabolites, TNF-α and IL-6 (P<0.001). Modafinil lowered NO metabolites, TNF-α, and IL-6 levels (P<0.001). Histopathology illustrated marked axonal degeneration and shrinkage in the cuffed sciatic nerve, which were improved in the modafinil-treated group. Modafinil exerts analgesic and neuroprotective effects in cuff-induced neuropathic mice via possible involvement of the nitrergic/inflammatory and serotonergic systems. [ABSTRACT FROM AUTHOR]