Specific Effect of Antipsychotics on Pituitary Volume: A Structural MRI Study

 

Rhonda M. El-Sheikh1, Frank P. MacMaster1, Ameet R. Upadhyaya1, Jeffrey Nutche2, David R. Rosenberg1, Matcheri S. Keshavan1

1Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI,2Western Psychiatric Institute & Clinic, University of Pittsburgh Medical Center, Pittsburgh, PA

 

Objective: Novel antipsychotics such as risperidone are known to affect pituitary function leading to robust prolactin elevations.  Increased prolactin may lead to structural alterations in pituitary volume. However, to date, no study has examined the effect of antipsychotics on pituitary volume or the specificity of such effects.

 

Methods: Magnetic resonance imaging (MRI) data will be presented from five samples (Table 1). Pituitary volumes were measured before and after treatment in a series of: 1) treatment naïve first episode psychotic (PSY) patients (primarily taking risperidone or olanzapine), 2) obsessive compulsive disorder (OCD) patients, 3) major depressive disorder (MDD) patients, and 4) attention deficit hyperactivity disorder (ADHD) patients. Similarly, healthy controls were scanned twice with scans being 52 weeks apart.

 

Results: Pituitary volume significantly increased in the PSY subjects after successful treatment, as opposed to healthy controls (t[17] = 2.44, p = 0.026, 11% increase; 1% increase respectively). Interestingly, risperidone produced larger increases in pituitary volume (13%) than olanzapine (3%). There was no effect of treatment noted in the OCD, MDD and ADHD groups, despite symptomatic improvement.

 

Conclusions: Pituitary volume increases appear specific to antipsychotic treatments, especially prolactin elevating drugs (i.e. risperidone) in contrast to prolactin sparing drugs (i.e. olanzapine).  Pituitary volumes may be a biomarker for treatment related neuroendocrine dysfunctions. Future studies should combine neuroendocrine measures with pituitary volumetric measures.

 

Table 1. Sample Information and Change in Pituitary Volume

Sample

Age Range (years)

Sex

Medication

Duration

Percent Change in Pituitary Volume

Psychosis

12-39

14M, 4F

Antipsychotic

52

11%*

OCD

7-18

9M, 15F

SSRI

12

1%

MDD

10-19

4M, 10F

SSRI

12

3%

ADHD

6-11

12M

Methylphenidate

8

1%

Healthy Controls

12-33

7M, 5F

None

52

1%

*Significant at p < 0.05