Therapeutic uses of compounds having combined sert, 5-HT3 and 5-HT1a activity

A method of treating mild cognitive impairment, the method comprising administering to a patient in need thereof a therapeutically effective amount of compound I, which is 1-[2-(2,4-dimethylphenylsulfanyl)phenyl]piperazine or a pharmaceutically acceptable salt thereof, to a patient in need thereof;

• wherein said method alleviates a symptom or complication of mild cognitive impairment, or delays the progression of mild cognitive impairment in the patient.