The hypothalamic-pituitary-adrenal axis: a target for intervention in early psychosis?

Pituitary volume and early treatment response in drug-naïve first-episode psychosis patients

BACKGROUND

An early response to antipsychotic treatment in patients with psychosis has been associated with a better course and outcome. However, factors that predict treatment response are not well understood. The onset of schizophrenia and related disorders has been associated with increased levels of stress and hyper-activation of the hypothalamic-pituitary-adrenal (HPA) axis. This study examined whether pituitary volume at the onset of psychosis may be a potential predictor of early treatment response in first-episode psychosis (FEP) patients.

METHODS

We investigated the relationship between baseline pituitary volume and symptomatic treatment response over 12 weeks using mixed model analysis in a sample of 42 drug-naïve or early treated FEP patients who participated in a controlled dose-finding study of quetiapine fumarate. Logistic regression was used to examine predictors of treatment response. Pituitary volume was measured from magnetic resonance imaging scans that were obtained upon entry into the trial.

RESULTS

Larger pituitary volume was associated with less improvement in overall psychotic symptoms (Brief Psychiatric Rating Scale (BPRS) P=0.031) and positive symptoms (BPRS positive symptom subscale P=0.010). Regardless of gender, patients with a pituitary volume at the 25th percentile (413 mm(3)) were approximately three times more likely to respond to treatment by week 12 than those at the 75th percentile (635 mm(3)) (odds ratio=3.07, CI: 0.90-10.48).

CONCLUSION

The association of baseline pituitary volumes with early treatment response highlights the importance of the HPA axis in emerging psychosis. Potential implications for treatment strategies in early psychosis are discussed.

Abnormalities of the HPA axis in affective disorders: clinical subtypes and potential treatments

BACKGROUND

New evidence is emerging regarding abnormalities of hypothalamic-pituitary-adrenal (HPA) axis function in subtypes of affective disorders. Adverse effects of HPA axis dysregulation may include dysfunction of monoaminergic transmitter systems, cognitive impairment and peripheral effects. Newer treatments specifically targeting the HPA axis are being developed.

OBJECTIVE

To review these developments focusing particularly on the glucocorticoid receptor (GR) antagonist mifepristone.

METHOD

A selective review of the literature.

RESULTS

The function of GRs is increasingly being defined. The role of corticotrophin-releasing hormone (CRH) and dehydroepiandrosterone (DHEA) in the brain is also increasingly understood. HPA axis function is particularly likely to be abnormal in psychotic depression and bipolar disorder, and it is in these conditions that trials of the GR antagonist mifepristone are being focused. CRH antagonists and DHEA are also being investigated as potential treatments.

CONCLUSION

Initial studies of mifepristone and other HPA-axis-targeting agents in psychotic depression and bipolar disorder are encouraging and confirmatory studies are awaited.