The present invention provides a method of treating, in a mammal, chronic fatigue syndrome CFS, chronic fatigue syndrome CFS that is associated with depression, a combination of chronic fatigue syndrome CFS and fibromyalgia syndrome FMS, fibromyalgia syndrome FMS associated with depression, pain and pain associated with depression. The method includes administering a therapeutically effective amount of a dual serotonin norepinephrine reuptake inhibitor compound or a pharmaceutically acceptable salt thereof.
