The invention relates to methods of treating, reducing the symptoms of, or preventing a post-traumatic stress syndrome by administration of tetrahydroquinoline derivatives of formula I wherein R1 and R2 each independently represent (C1-C4)alkoxy, R3 represents aryl-(C1-C4)alkyl or heteroaryl-(C1-C4)alkyl, and R4 represents hydrogen or (C1-C4)alkyl, or pharmaceutically acceptable salts thereof.”