MYOINOSITOL IN DEPRESSIVE AND HEALTHY-SUBJECTS DETERMINED BY FRONTAL H-1-MAGNETIC RESONANCE SPECTROSCOPY AT 1.5 TESLA

Myo-inositol (mI) as a precursor in the phosphatidylinositol second me ssenger system has been reported to be reduced in depression. By means of proton-magnetic resonance spectroscopy (H-1-MRS) the mi levels in the frontal brain were investigated in vivo in the present study. Twen ty-two patients (mean age: 42.8 +/- 10.7 years) with depressive episod es according to ICD 10 (HAMD score > 17) were compared to 22 healthy s ubjects (28.0 +/- 5.3 years). Two voxels (30 x 20 x 20 mm(3)) in the f rontal lobes were examined in a Siemens Magnetom SP 4000 at 1.5 T (STE AM sequence: TR = 3500 ms, TE = 55 ms). With the total creatine (Cr) a s an internal standard, mI/Cr ratios were calculated to follow the mi levels. In the left frontal lobe, mI/Cr was 0.43 +/- 0.06 in depressiv e patients and 0.46 +/- 0.07 in healthy subjects; concerning the right frontal lobe, mI/Cr was 0.46 +/- 0.08 and 0.48 +/- 0.06, respectively . There were neither significant differences between the two groups no r between the hemispheres. Since there was a significant positive corr elation (R = 0.6) between the age and the mI/Cr in the right frontal l obe of depressed patients, age matched pairs analysis was performed (n = 2 x 10, in each group: nine females, one male, < 40 years). In the right frontal lobe, the patients' mI/Cr of 0.40 +/- 0.05 was now signi ficantly lower than the controls' mI/Cr of 0.45+/-0.06. However, most of the patients were on antidepressive medication. Interestingly, it w as exactly this group of patients which showed significantly lower mi levels. We regard our investigation as a pilot study which suggests an influence of age and antidepressants on mi levels and should be taken into consideration in further investigations in depressive patients. (C) 1998 Elsevier Science Ltd. All rights reserved.