Hypothalamic-pituitary-adrenal axis

What is the hypothalamic-pituitary-adrenal (HPA) axis? 

Stress is defined as a threat to the body’s ability to regulate internal processes following exposure to an adverse event. People adapt physiologically and behaviourally in response to stress in order to re-establish internal balance. The biological response to stress is mediated through the HPA axis and the sympathetic nervous system. This is achieved through the release of cortisol and adrenocorticotropin hormone (ACTH). Altered HPA axis activity can result in prolonged exposure to cortisol or ACTH which can be detrimental to physical and psychological health. HPA activity can be measured by basal cortisol and ACTH levels in an unstressed or resting state. HPA activity can also be measured after a stressful stimulus (chemical or psychological). There is evidence that the HPA axis may be dysfunctional in a number of mental disorders, including schizophrenia.

What is the evidence on HPA axis functioning?

Moderate quality evidence suggests cortisol may be increased in people with schizophrenia and in people at clinical high-risk of the disorder. Moderate to low quality evidence suggests that cortisol may be related to increased symptom severity. The cortisol and ACTH responses to psychological stress is diminished in schizophrenia, however the magnitude is unclear. Non-suppression of cortisol levels may be associated with suicide and depression, but not with positive symptoms. An inconsistent association was reported with negative symptoms.

March 2019

Last updated at: 12:03 am, 26th March 2019
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