Objective. To study clinical and psychophysiological characteristics of asthenic disorders in adolescent girls in the aspect of treatment efficacy of cortexin. Material and methods. Seventy-five women, aged 14—17 years, who were diagnosed with neurasthenia (ICD-10 F.48.0), were examined. Conventional neurological examination, a 10-point Visual Analogue Scale, the Multidimensional Fatigue Inventory (MFI-20), the A.M. Vein questionnaire, the Spielberger-Khanin questionnaire and EEG were used. Results and Conclusion. The high level of anxiety resulted in the development of autonomic symptoms and cephalgia. The EEG study showed that women with neurasthenia were characterized by lower alpha-rhythm power in the occipital sites compared with healthy peers. Treatment with cortexin improved patient’s condition in 80% of cases that was supported by the positive EG dynamics.