Objective: Magnetic Resonance Spectroscopy (MRS) is a noninvasive in vivo technique
extensively applied to assess the levels of neural metabolites in the brain. We aimed to summarize
the findings of proton spectroscopy (1H MRS) studies addressing neuro-metabolite findings in the
Basal Ganglia (BG) of patients with Bipolar Disorders (BD).
Method: A search of PubMed and Ovid databases was conducted to identify ¹H MRS studies since
1990 reporting N-acetylaspartate (NAA), phosphocholine plus glycerophosphocholine (PC+GPC),
and creatine plus phosphocreatine (Cr+PCr) levels in the BG of patients with BD.
Results: Ten original studies were included in this review. Three studies involved BD patients with
depressed mood, six studied euthymic BD patients, and one study looked at manic subjects. In depressed
BD patients, three studies reported elevated PC+GPC and Cr+PCr levels in the caudate and
putamen. NAA levels were found to be elevated in two of the studies, while one reported no change.
In euthymic BD patients, five studies reported no group differences with respect to any metabolites,
and one study found differences in PC+GPC/Cr+PCr associated with lithium treatment. In mania,
lower PC+GPC, lower NAA levels, and increased Cr+PCr levels were described in the caudate of
BD patients compared to HC.
Conclusion: This review suggests that abnormalities in NAA, GPC+PC, and Cr+PCr levels in the
BG might be associated with mood state among BD patients. In addition, the methodological issues
involved in the heterogeneity of 1H MRS findings in BD, as well as the potential role of 1H MRS
findings as biomarkers for BD, are discussed.