Exogenous factors in panic disorder: clinical and research implications.

Because panic disorder has an underlying biologic and probably genetic basis, the role of factors outside the organism in initiating and sustaining panic is often overlooked. The authors review certain exogenous factors that seem capable of triggering attacks and/or increasing their frequency and intensity: self-administered pharmacologic agents (caffeine, alcohol, nicotine, over-the-counter cold preparations, cannabis, cocaine); habits (sleep deprivation, diet, exercise, relaxation, hyperventilation); and aspects of the environment (fluorescent lighting, life stressors). There may be a specificity to the action of some of these factors, because certain factors previously thought to trigger panic attacks (e.g., pain, hypoglycemia) have been proved not to have this effect. Although the clinical significance of many of the exogenous factors discussed still awaits empirical confirmation, attention to such factors during the initial evaluation of a patient with panic disorder may be helpful in formulating a successful treatment plan.