Changes in brain Glx in depressed bipolar patients treated with lamotrigine: A proton MRS study.
Level 4 - case-series / case-control
Uncontrolled prospective pre-post study (single-arm case series)
PubMed 30599363 · doi:10.1016/j.jad.2018.12.092
What was done
Twenty-one patients with bipolar disorder experiencing a depressive episode received lamotrigine for 10 to 12 weeks. Proton magnetic resonance spectroscopy (MRS) at 3 Tesla was performed at baseline and after treatment to assess glutamate levels (measured as Glx) in the anterior cingulate cortex (ACC). The study examined overall Glx changes and whether baseline Glx predicted clinical response.
What was found
Lamotrigine treatment had no significant overall effect on ACC Glx concentrations across the entire sample. However, patients who responded clinically showed a significant increase in ACC Glx levels post-treatment. Baseline Glx levels did not predict clinical response to lamotrigine. The abstract reported no specific numerical values or p-values.
Why it matters
The findings suggest that lamotrigine does not systematically reduce cortical glutamate in humans despite animal model predictions, and indicate that clinical improvement may correlate with increased anterior cingulate glutamatergic activity.
Limits
The study had a small sample size (n = 21) and no control group. Most participants were taking concomitant medications that may have influenced glutamate activity, and 3T MRS measured combined Glx rather than resolving glutamate separately from glutamine.
Cited by
- contradicts Lamotrigine treatment typically produces reductions in brain glutamate levels over a period of approximately three months.