HPA axis and stress
Cortisol and depression
Corticosteroids have long been known to be capable of altering a patient's mental status. High doses given acutely can lead to euphoria and long-term administration can lead to depression. Physiologically, it is also known that many patients with depression have increased production of CRH (corticoid releasing hormone) in the brain, and increased production of cortisol which results in increased concentrations of circulating cortisol.
It is therefore hypothesized that emotional stress can lead to increases in circulating cortisol levels, which then leads to decreased function of the corticosteroid receptors and an inhibition of neurotransmission. With continued stress, the ability of the body to self-regulate cortisol output is lost and this results in a patient with an altered mood.
The dexamethasone suppression test is often positive in depressed individuals. A positive test finds that after the administration of dexamethasone there is:
Extra info: As many as 50% of depressed patients hypersecrete cortisol and lack the ability to supress cortisol after desamethasone administration. This is indicative of a patient with HPA axis overactivity.
Emotions result in altered neurotransmission and levels of stress hormones.