[Anxiety, panic and the hypothalamic-pituitary-adrenal axis].
OBJECTIVE
This article focuses on the differential activation of the hypothalamic-pituitary-adrenal axis in generalized anxiety disorder and panic disorder.


METHODS
The results of recently reported reviews of the literature are summarized and discussed.


RESULTS
The results of experimental studies that assayed adrenocorticotropic hormone, cortisol and prolactin show that real-life panic attacks, as well as those induced by selective panicogenic agents such as lactate and carbon dioxide, do not activate the hypothalamic-pituitary-adrenal axis. Agonists of the cholecystokinin receptor B such as the cholecystokinin-4 peptide and pentagastrin increase stress hormones regardless of the occurrence of a panic attack and, thus, seem to activate the hypothalamic-pituitary-adrenal axis directly. The benzodiazepine antagonist flumazenil does not increase stress hormones, but this agent does not reliably induce panic attacks. Pharmacological agents that increase anxiety in both normal people and panic patients (caffeine, yohimbine, serotonergic agonists) raise stress hormone levels.


CONCLUSIONS
In addition to the differences in symptomatology and pharmacological response, generalized anxiety disorder and panic disorder affect stress hormones in distinct ways. While anticipatory anxiety and generalized anxiety disorder activate both the hypothalamic-pituitary-adrenal and the sympathoadrenal axes, panic attack causes major sympathetic activation, but has little effect on the hypothalamic-pituitary-adrenal axis.
Graeff
Frederico G
FG
Divisão de psiquiatria, Departamento de Neurologia, Psiquiatria e Psicologia Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil. hegog@hotmail.com
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D004195:Disease Models, Animal; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism / Q000503:physiopathology*; D019344:Lactic Acid / Q000378:metabolism; D016584:Panic Disorder / Q000378:metabolism / Q000503:physiopathology* / Q000523:psychology; D010913:Pituitary-Adrenal System / Q000378:metabolism / Q000503:physiopathology*; D011388:Prolactin / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*
D002245:Carbon Dioxide; D019344:Lactic Acid; D000324:Adrenocorticotropic Hormone; D011388:Prolactin