Patients with bipolar disorder show
enlarged pituitary gland volume relative to mentally healthy
controls, results from a magnetic resonance imaging study (MRI)
show.

However, the first-degree relatives of these patients showed no
such enlargement, arguing against an overt genetic component of
pituitary volume.

“Abnormalities of the hypothalamic-pituitary-adrenal (HPA) axis,
the primary biological system mediating the stress response, are
thought to reflect stress-related dysregulation and have been
described in patients with bipolar disorder,” Tsutomu Takahashi
(Melbourne Neuropsychiatry Centre, Victoria, Australia) and
colleagues comment in the Journal of Affective
Disorders.

Imaging studies of pituitary volume in bipolar disorder patients
have so far been inconsistent, perhaps owing to illness
heterogeneity and different sample characteristics such as
psychosis, symptom severity, illness stage, and treatment
status.

In the current study, the researchers used MRI to assess
pituitary volume in 29 remitted patients with chronic bipolar
disorder, 49 of their first-degree relatives (of whom 15 had a
diagnosis of major depressive disorder [MDD] ), and 52 age- and
gender-matched mentally healthy controls.

Bipolar disorder patients had a significantly larger pituitary
volume than their relatives and controls, but there was no
difference between the bipolar disorder relatives and controls.

Also, pituitary volume did not differ between the MDD relatives,
non-MDD relatives, and control individuals.

Bipolar disorder patients treated with lithium (n=12) tended to
have smaller pituitary volumes compared to those not on lithium,
but this did not reach statistical significance.

“It may be possible that trait-related HPA axis dysregulation
precedes the illness onset but development of clinical phenotype of
bipolar disorder and pituitary volume changes depends on additional
environmental (eg, life events, stress) and other factors,” the
researchers comment.

They say that additional assessment of both pituitary volume and
hormonal levels, for example cortisol and corticotropin, at various
illness stages would be required to further examine the role of HPA
axis dysfunction in the pathophysiology of bipolar disorder.

MedWire (www.medwire-news.md) is an independent clinical news
service provided by Current Medicine Group, a trading division of
Springer Healthcare Limited. © Springer Healthcare Ltd;
2010

Free abstract

• Break-through Preventative Care Program For People Living With Bipolar Disorder
• Antiepileptic Drugs Not Associated With Increased Risk Of Suicide Attempts In Patients With Bipolar Disorder
• AstraZeneca Traveling Exhibit Helps Americans Understand And Manage Bipolar Depression
• Research Supports Toxoplasmosis Link To Schizophrenia
• Funding Supports ADA Technologies' Development Of Home Monitor For Bipolar Disorder
• Interactive Autism Network Opens Its Doors To Adults With Autism

No Comments »

No comments yet.

RSS feed for comments on this post. TrackBack URL

Leave a comment

You must be logged in to post a comment.