Method of treating schizophrenia, depression and other neurological conditions

A method of treating or preventing schizophrenia, depression, stroke, head injury, nicotine withdrawal, spinal cord injury, anxiety, pollakiuria, incontinence of urine, myotonic dystrophy, attention deficit hyperactivity disorder, excessive daytime sleepiness (narcolepsy), Parkinson's disease or autism in a mammal, which comprises administering an effective amount of at least one of the following compounds of the formula (I) to a mammal in need thereof:

• wherein:
• R1 is lower alkyl, aryl, ar(lower)alkoxy or a heterocyclic group, each of which is optionally substituted with halogen;
• R2 is hydrogen or lower alkyl;
• R3 is cyclo(lower)alkyl, aryl or ar(lower)alkyl, each of which is optionally substituted with halogen;
• A is
• —SO2— or lower alkylene;
• and
• Y is
• —SO2— or
• or a pharmaceutically acceptable salt or hydrate thereof.