Background:This study aimed to evaluate the effect of methylphenidate for treating mental sequelae after traumatic brain injury (TBI).Methods:Thirty-six patients with TBI were randomly divided into the intervention group and placebo group. The participants in the intervention group received methylphenidate, while subjects in the placebo group were administered a placebo. This study was conducted from January 2014 to December 2016. The outcome measurements included Mental Fatigue Scale, Choice Reaction Time, Compensatory Tracking Task, Mental Arithmetic Test, Digit Symbol Substitution Test, Mini-Mental State Examination (MMSE), Beck Depression Inventory (BDI), and Hamilton Rating Scale for Depression. In addition, safety was also recorded and assessed.Results:A total of 33 subjects completed the study. Methylphenidate showed greater efficacy than placebo, with decreased scores on the Mental Fatigue Scale, Choice Reaction Time, and Compensatory Tracking Task in the intervention group compared to the placebo group (P < .01, respectively). Furthermore, increased scores on the Mental Arithmetic Test, Digit Symbol Substitution Test, and MMSE in the intervention group, compared to those in the placebo group (P < .01 respectively), were observed. In addition, a significant difference in the scores on the BDI (P = .04) and Hamilton Rating Scale for Depression (P = .005) was observed between the 2 groups. The safety at the end of the 30 week-treatment was similar between the 2 groups (P > .05).Conclusion:The results of this study demonstrated that methylphenidate could effectively improve mental fatigue and cognitive functions in patients with TBI.