[Proton magnetic resonance spectroscopy of prefrontal lobe and thalamus in schizophrenics: correlation with clinical characteristics].

OBJECTIVE

To explore the characteristics of different subtypes of schizophrenics on prefrontal lobe and thalamus by proton magnetic resonance spectroscopy ((1)H-MRS) and its relationship.

METHODS

From August 2007 to April 2010 at our center, a total of 159 schizophrenics fulfilling the third edition criteria of Chinese Classification of Mental Disorders (CCMD-III) were recruited. And prefrontal lobe and thalamus were evaluated by multi-voxel (1)H-MRS. There were 88 males and 71 females. There were first-episode (n = 54) and not-first-episode (n = 105), negative subtype (n = 125) and positive subtype (n = 34), medicated (n = 96) and non-medicated (n = 63) by different criteria. The levels of N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine compounds (Cr) were measured and the ratios of NAA/Cr and Cho/Cr determined. Positive and negative syndrome scale (PANSS) and Wisconsin card sorting test (WCST) were also assessed. Only 45 normal controls received (1)H-MRS.

RESULTS

On left prefrontal lobe and left thalamus, the NAA/Cr ratios in different subtypes of patients were lower than those in normal controls (P < 0.05 or 0.01). The NAA/Cr ratios in patients of non-first-episode (1.48 ± 0.34), negative subtype (1.40 ± 0.35) and medicated (1.47 ± 0.36) on right thalamus were also lower than those in normal controls (1.62 ± 0.37, t = 2.25, 3.56, 2.28, P < 0.05 or P < 0.01). Compared with positive subtype schizophrenics, the NAA/Cr ratios in those of negative subtype on right thalamus were lower (1.40 ± 0.35 vs 1.60 ± 0.37, t = 2.92, P < 0.01). On right thalamus of non-medicated schizophrenics, there was a negative correlation between the duration of illness and the ratio of NAA/Cr (r = -0.38, P < 0.05) and a positive correlation between the duration of illness and the ratio of Cho/Cr (r = 0.43, P < 0.01). On right thalamus of negative subtype schizophrenics, the ratios of NAA/Cr were negatively correlated with the total score of PANSS and the score of negative factor respectively (r = -0.36, -0.40, P < 0.05). On left prefrontal lobe of different subtypes, the ratios of NAA/Cr were negatively correlated with the total score of PANSS, the score of negative factor, responses errors and persistent errors (P < 0.01) and positively correlated with completed categories and conceptual level responses (P < 0.05 or P < 0.01).

CONCLUSION

Abnormalities in neuronal function and/or integrity are present on left prefrontal lobe and left thalamus in schizophrenics. And right thalamus is probably involved in non-first-episode subtype, negative subtype and non-medicated subtype. Different subtypes of schizophrenics may have different characteristics of (1)H-MRS due to the duration of illness and their clinical symptoms.