Brain lactate and pH in schizophrenia and bipolar disorder: a systematic review of findings from magnetic resonance studies.
Level 4 - case-series / case-control
Systematic review of case-control neuroimaging studies
PubMed 29581538 · doi:10.1038/s41386-018-0041-9
What was done
A systematic review of Medline/PubMed and EBSCO databases was conducted to identify case-control magnetic resonance spectroscopy (MRS) studies assessing brain lactate or pH levels in patients with schizophrenia, bipolar disorder, or both compared to controls.
What was found
A total of 33 studies met inclusion criteria (7 lactate studies and 26 pH studies). In bipolar disorder, 5 of 6 studies found elevated brain lactate (primarily in the cingulate cortex), and 4 of 13 studies reported decreased frontal lobe pH. In schizophrenia, 1 study evaluated lactate and reported an elevation, while 2 of 13 studies evaluating pH reported a reduction. No consistent associations were identified between lactate or pH alterations and medication exposure, disease subtype, mood state, or other clinical characteristics.
Why it matters
The findings provide preliminary neuroimaging support for energy metabolism abnormalities—specifically elevated lactate indicative of shifted glycolysis—in bipolar disorder, while demonstrating that evidence for similar alterations in schizophrenia is currently sparse.
Limits
The total evidence base is small, particularly for lactate measurements (only 1 study in schizophrenia and 6 in bipolar disorder). The abstract reports vote-counting of study outcomes rather than quantitative meta-analytic effect sizes or confidence intervals, and confounding factors such as psychotropic medication use, disease state, and lifestyle variables could not be systematically accounted for.
Cited by
- supports Levels of lactate were observed to be elevated in serious mental illness.