Depressive psychosis: clinical usefulness of MR spectroscopy data in predicting prognosis

To prospectively assess the usefulness of magnetic resonance (MR) spectroscopy data acquired before the initiation of medical therapy in predicting prognosis in patients with depressive psychosis.

All subjects gave written informed consent to an institutional committee for clinical research-approved study protocol. The clinical course after medication in 52 patients with depressive psychosis (age range, 52-78 years; 21 men, 31 women) was investigated. In all patients, MR spectroscopy was performed with a 1.5-T MR imaging unit before the initiation of medical therapy. Cerebrovascular lesions (CVLs), which appear as high-signal-intensity areas on T2-weighted MR images, were evaluated by using the Fazekas rating scale. Patients were classified into two groups on the basis of the ratio of N-acetylaspartate (NAA) to creatine and phosphocreatine (Cr): Patients in group A had an NAA/Cr ratio greater than 1.91, and patients in group B had an NAA/Cr ratio of 1.91 or less. To assess the response of the patients to medication, standard psychiatric tests--the Verbal Associative Fluency Test (VAFT), the Digit Symbol Test (DST), the Mini-Mental State Examination (MMSE), and the Hamilton Depression Rating Scale (HAM-D)--were administered before and after medical therapy was initiated. Mean test scores before and after medication were compared with paired t testing. P < .05 was considered to indicate a significant difference.

There were 25 patients in group A and 27 in group B. In group A, the mean VAFT and DST scores increased and the mean HAM-D score decreased after medication. There was no significant difference in mean MMSE scores before and after medication (P = .945 for group A and P = .934 for group B). In group B, there were no significant differences in any of the psychiatric test scores before and after medication. The high-signal-intensity area score in group B was significantly higher than that in group A (P = .004).

MR spectroscopy data obtained before the initiation of medical therapy were useful in predicting prognosis in patients with depressive psychosis; this suggests that the combined burden of all CVLs may affect the response to antidepressant medication.