the invention is directed to the use of a compound of formula i as defined herein , a pharmaceutically acceptable salt thereof ; or a pharmaceutical composition containing a compound of formula i , in treating a mammal , including a human , for a psychiatric disorder or condition selected from the group consisting of depression , mood disorders , anxiety , schizophrenia , bipolar disorder , addiction , cognitive impairment , parkinson &# 39 ; s and alzheimer &# 39 ; s diseases .