Background: Given that on the one side considerable similarities between hypochondriasis and obsessive- compulsive disorder (OCD) by means of sharing a number of features, including intrusive thoughts and repeated checking (Barsky, 1992), on the other side similar structural neuroimaging data that found hypochondriac patients to have significantly smaller mean left and right OFC, and greater left thalamus volumes compared to those of healthy controls. Aims: We considered to investigate the hippocampal neurochemicals, found changed in OCD patients, in hypochondriac patients. Methods: Fifteen patients with hypochondriasis, recruited from our out- or in-patient clinics, were compared with 15 healthy control comparisons in regard to proton magnetic resonance spectroscopy (1H-MRS) imaging of hippocampus. Results: The patients with hypochondriasis had lower right and left NAA/CHO, and NAA/CRE, and near-significant lower right CHO/CRE hippocampal ratios than healthy matched comparison subjects. Conclusion: The data of the present investigation in patients with hypochondriasis provide preliminary evidence of lower right and left NAA/CHO, and NAA/CRE, near-significant lower right CHO/CRE hippocampal ratios, revealing neurochemical alterations in hippocampus and a further support the notion that hypochondriasis shares a variety of neurobiological similarities with OCD.
Hypochondriasis, a somatoform disorder according to Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV), preoccupation with fears of having, or the idea that one has, a serious disease based on the person’s misinterpretation of bodily symptoms despite repetitive medical evaluation and reassurance. In the etiology of hypochondriasis, psychosocial factors particularly psychodynamic explanations have been always leaded until last years. However, even though they are limited, investigations have been started to account for neurobiological basis of hypochondriasis. In this context, our research team also carried out some neuroradiological studies in hypochondriasis. One of them, we volumetrically evaluated the orbito-frontal cortex (OFC), anterior cingulate, caudate nucleus, and thalamus volumes in hypochondriac patients and determined that hypochondriac patients had significantly smaller mean left and right OFC, and greater left but not right thalamus volumes compared with healthy controls, without any differences on caudate and anterior cingulate volumes. So, in that investigation, we suggested that abnormalities in the OFC and thalamus might play an important role in the pathophysiology of hypochondriasis. In another structural study, we examined possible alterations in the pituitary anatomy in patients with hypochondriasis by means of quantitative MRI which was the first MRI investigation of pituitary of the patients with hypochondriasis [
Fifteen patients recruited from the psychiatric in or outpatient’s clinic, at the Firat University School of Medicine Department of Psychiatry in Elazig, and eighteen healthy controls who were all right handed, and had a mean age of 28.1 ± 3.4 and 30.6 ± 4.2 years, respectively, were the subjects of this study. Normal volunteers were recruited from the hospital staff. Diagnoses were made by using the Structured Clinical Interview for DSM-IV (SCID) [
Briefly, MRI and 1H-MRSI scans were acquired using a GE Signa Excite 1.5 T whole body scanner (GE Medical Systems, Milwaukee, Wisconsin), with the following values (repetition time [TR] = 2000 ms, echo time [TE] = 15.6 ms, field of view [FOV] = 240 mm, flip angle = 200, bandwidth = 20.8, slice thickness = 2.4 mm, echo spacing = 15.6 ms, 8 echoes, resolution = 0.9375 × 0.9375 × 2.4 mm).
We investigated following neurochemical markers; NAA, CRE, and CHO. For all voxels, NAA, CHO, and CRE peaks were determined automatically. Position of hippocampal voxels and sample magnetic resonance spectrum are presented in
In addition to 1H-MRSI scans, hippocampus of the patients and healthy controls were structurally measured. In the tracings of the hippocampus, it was benefited from standard anatomic atlases [5-7] and from Caetano et al. [
completely connected with the thalamus and finished one slice before the mammilary bodies appeared. The lateral border was accepted as the inferior horn of the lateral ventricle. As the superior border of the hippocampus, the corona radiata and ambient cistern were accepted. The inferior border was selected as the white matter.
The statistical analyses were performed using SPSS version 13.0 (SPSS, Chicago, IL). Independent t test was used to assess differences in the volumes of hippocampus, whole brain, metabolite values, and some demographical data. Correlation analyses between volume measurements and clinical and demographic variables were carried out by means of Pearson’s correlation coefficients. For the camparisons of each metabolite ratio, NAA/CRE, NAA/ CHO, and CHO/CRE, independent t test was used. The criterion of significance level was set at p < 0.05.