An aim of a randomized blind study was to assess therapeutic efficacy and safety of ladasten used as an antiastenic drug in patients with neurasthenia. Tasks of the study included the investigation of characteristics of therapeutical actions, efficacy of the drug comparing to placebo, possible side-effects and probability of the development of "withdrawal syndromes". The design of the study included a wash-out period, a monotherapy with ladasten and placebo during 28 days and a final 1-week period of receiving placebo. Standartisized objective and subjective methods of mental state evaluation in patients were administered. The results obtained suggest that a combination of psychostimulant and anxiolytic actions in the spectrum of psychotropic activity of ladasten determines the its high therapeutic efficacy in asthenic disorders. It has been found that ladasten is superior in the rate and degree of reduction of main symptoms of asthenic syndrome compared to placebo. The absence of "withdrawal syndrome" after the drug withdrawal reveals the lack of addictive potential in this drug.