Clinico-epidemiological and repeated catamnestic investigations were p
erformed in juveniles and individuals of young age (14-26 year old) in
relation to prevalence, structure and dynamics of premorbid neurologi
cal disorders and typical personality reactions. Observations were car
ried out every 4 years. Results of analysis testified the development
of borderline mental disorders in one third of teenagers with preneuro
tic and pronounced characterological reactions. That permitted to cons
ider these deviations as ''risk factors'' of the appearance of both ne
uroses and psychopathies.