Pituitary volume and third ventricle width in euthymic patients with bipolar disorder

Area of Science:

• Neuroendocrinology
• Psychiatry
• Neuroimaging

Background:

• Bipolar disorder (BD) exhibits clinical and neuroendocrine features linked to hypothalamic dysfunction.
• While direct hypothalamic imaging is challenging, the third ventricle and pituitary offer indirect structural insights.
• Investigating these adjacent structures can reveal neurobiological underpinnings of BD.

Purpose of the Study:

• To examine the structure and function of the hypothalamic-pituitary-adrenal (HPA) axis in euthymic patients with bipolar disorder.
• To compare pituitary volume and third ventricle width in bipolar disorder patients versus healthy controls.

Main Methods:

• Magnetic Resonance Imaging (MRI) was used to assess pituitary volume and third ventricle width in 49 euthymic adults with bipolar disorder and 47 matched controls.
• Basal salivary cortisol levels were measured to assess HPA axis function.
• Statistical analyses, including ANOVA, were employed to compare groups and identify correlations.

Main Results:

• Patients with bipolar disorder had significantly wider third ventricles than controls, particularly males.
• Third ventricle width correlated positively with age.
• While overall pituitary volumes did not differ, female bipolar disorder patients had smaller pituitaries than female controls.
• No differences in basal salivary cortisol levels were observed between groups.

Conclusions:

• Euthymic bipolar disorder patients exhibit distinct pituitary and third ventricle structures compared to controls, despite normal basal cortisol.
• These structural differences, particularly those related to gender, may play a role in bipolar disorder pathogenesis.
• Findings suggest potential trait abnormalities or consequences of illness episodes impacting neuroendocrine regulation in bipolar disorder.