A woman aged 35 has been suffering with pulmonary tuberculosis for 10 years. When in physiatric clinic, she started to act strangely: put on a gaudy make-up, gathered the other patients around herself, was singing and dancing with them. Highly excited, passed all the time among males, flirted, started sexually-biased conversations. The whole night absented from the clinic ("was on a date"). What leading syndrome of mental disorders is observed?