Functional assessment of higher mental functions in case of intoxication or during treatment will make it possible to identify predictors of the symptoms of hepatic encephalopathy associated with portal hypertension. The study was aimed to determine the diagnostic predictors of the emergence of the earliest symptoms of hepatic encephalopathy in adolescents with portal hypertension. The study involved 60 adolescents aged 13–17 years: 28 males, 32 females. The experimental group included 30 adolescents with the diagnosis К76.6 Portal hypertension, unspecified form. The control group included 30 adolescents with normal somatic status, who had no mental disorders, traumatic brain injuries or severe infectious diseases of the brain (based on the records of the annual check-up). The studied groups were matched by sex, age, and social status. The proprietary method, Tobii EyeX hardware and software system (GazeControl software), and Cambridge Face Memory Test for Children (CFMT-C) were used. It has been found that recognition of single face images, multiple face images, and multiple face images camouflaged with noise by adolescents with portal hypertension is associated with the greater efforts (manifested in the increased number and duration of gaze fixations), than recognition of the above by adolescents with normal somatic status. The accuracy of recognition of single face images, multiple face images, and multiple face images camouflaged with noise shown by adolescents with portal hypertension experiencing the toxic effects associated with manifestations of hepatic encephalopathy is significantly reduced compared to that shown by adolescents with normal somatic status. The results obtained can be considered as the diagnostic predictors allowing one to trace the changes in the hepatic encephalopathy severity at various stages of treatment (including after surgical intervention).