The present invention provides a method of preventing or reducing the severity of a stress-associated condition in a subject by systemically administering to the subject an effective amount of brimonidine or a pharmaceutically acceptable salt, ester, amide, sterioisomer or racemic mixture thereof. Stress-associated conditions that can be treated according to a method of the invention include, but are not limited to, dyspepsia, tachycardias other than tachycardia associated with myocardial ischemia, panic attack, non-inflammatory dermatogical conditions, disorders of muscle contraction, sensory hypersensitivity associated with migraine, and behavioral disorders.