The present invention relates to the use of one or more expression vectors comprising certain nucleic acid sequences encoding a combination of NPY and/or one or more of its receptors (Y1, Y2, Y4, Y5, y6), and/or galanin and/or one or more of its receptors (GALR1, GALR2, GALR3), and/or somatostatin and/or one or more of its receptors (SST1, SST2, SST3, SST4, SST5), in the preparation of a medicament for treatment of a disorder of the nervous system, such as a neurological or a psychiatric disease chosen from epilepsy, depression, and anxiety. The invention further relates to vectors that comprise nucleic acid sequences encoding the above combination, to compositions comprising such vectors and to a method of delivery and expression of the above combination of nucleic acid sequences into cells of the nervous system to treat neurological or psychiatric diseases in humans or animals.