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Studies of depressed adults have shown abnormalities in cerebral energy metabolism, as noted by low brain levels of nucleoside triphosphate (NTP), which primarily represents adenosine triphosphate (ATP). This study was undertaken to determine whether proton magnetic resonance spectroscopy (1H MRS) measures of the low-field purine resonance, which arises primarily from adenosine phosphates, can be used to assess abnormalities in cerebral purine metabolism in depressed adults.Data from 1H MRS and phosphorus-31 (31P) MRS were acquired for depressed and nondepressed comparison subjects. Intensities of the purine resonance, by 1H MRS (7.5-8.5 ppm), and of NTP, by 31P MRS, were determined.Purine resonance intensities did not differ on average between depressed patients and comparison subjects. However, purine levels were approximately 30% lower in female depressed subjects who subsequently responded to fluoxetine treatment than in those who did not respond. Beta-NTP was lower by 21% in responders than in nonresponders and was correlated with purine levels for the depressed subjects.Brain purine levels are low in female depressed patients who respond to treatment with fluoxetine, suggesting that response to treatment might be predicted by using 1H MRS. These observations also suggest that agents that increase brain adenosine levels may have antidepressant efficacy.

OBJECTIVE: Studies have identified two types of antidepressant response: true drug response and placebo pattern response. This study examined the relationship between true drug response and choline-creatine ratios in the basal ganglia of depressed patients treated with fluoxetine. METHOD: The authors evaluated drug-free outpatients with major depression before (N=41) and after (N=15) 8 weeks of fluoxetine treatment, 20 mg/day, by using proton magnetic resonance spectroscopy. RESULTS: There was a significant difference in the degree of change from baseline to week 8 in choline-creatine ratios between the true drug response group (N=8) and the placebo pattern response/nonresponse group (N=7); the true drug response patients had a 20% increase in choline-creatine ratios, and the placebo pattern response/nonresponse patients had a 12% decrease in choline-creatine ratios. CONCLUSIONS: These data suggest that true drug response to fluoxetine treatment in depression may be associated with an increase in choline-...

Objective: The purpose of this study was to evaluate whether the concentration of β-nucleoside triphosphate is lower in the basal ganglia of depressed subjects. Method: In vivo 31P magnetic resonance spectra were acquired from a 45-cm3 region surrounding the basal ganglia of 35 unmedicated depressed subjects and 18 comparison subjects. Results: β-Nucleoside triphosphate, which arises primarily from β-ATP, was 16% lower in the depressed subjects than in the comparison subjects. Conclusions: The low level of β-nucleoside triphosphate is consistent with an abnormality of high-energy phosphate metabolism in the basal ganglia of subjects with major depression. (Am J Psychiatry 1997; 154:116‐118)