I wrote something up on this before. I take high dosage Lyrica (pregabalin) for my bipolar disorder and I'm an advocate for the gabapentinoids for that and anxiety disorders. I wrote a paper about levetiracetam that I'll share here. It's not very helpful, but I wrote it and it's relevant:
My hypothesis is that levetiracetam [Keppra; Keppra XR] may be an efficacious mood stabilizer indicated for bipolar patients that particularly respond to gabapentin/pregabalin's mood stabilization effect but not necessarily its anxiolytic effect.
Levetiracetam is the S-enantiomer of etiracetam, a structural derivative of piracetam. (via my very own analysis, the addition of ethylene to piracetam --> etiracetam, but I did not verify). It is subjacent to OTC piracetam for cognitive enhancement; however, in psychiatric conditions, such as schizophrenia and bipolar disorder, AEDs such as levetiracetam appear to have clear roles based on their effect on intracellular pathways. Levetiracetam displays mood stabilizing properties (Epilepsy Behav. 2004 Apr;5(2):204-15.), but it has not been well-studied.
Clinical trials for gabapentin/pregabalin as mood stabilizers for bipolar disorder, particularly mania, have suggested that they are not effective. Au courant, some patients, including myself, have responded well to gabapentin/pregabalin for bipolar, and I propose that levetiracetam shares properties similar that may parturitate a beneficial outcome for bipolar patients, such as myself, that have responded to gabapentin/pregabalin.
"Gabapentin and pregabalin block P/Q-type VDCCs to reduce glutamate release, presynaptically." (Eur J Neurosci. 2004;20:15661576). "Levetiracetam preferentially acts on P/Q-type VDCCs to decrease the amount of Ca2+ influx, reduce glutamate release and thus modulate synaptic activity in the DG." (CY Lee - 2009) Gabapentin/pregabalin, they specifically effect the alpha 1A subunit; (Volume 1359, 4 November 2010, Pages 298303): in my own terms, levetiracetam acts on CACNA1A just like gabapentin/pregabalin.
The normal mood-stabilizing property action of levetiracetam as an AED combined with its action on CANA1A mimicing gabapentinoids make it a novel choice for patients who have responded to them.
A related medication that has experimental research for use in bipolar disorder with action on CANA1A is verapamil, but its actions are not very significant and essentially irrelevant, but still investigatory. Lamotrigine is involved with mutations on the receptor, but is not as directly involved as verapamil and especially levetiracetam.
I propose levetiracetam to be studied as a psychotropic to be studied more extensively for cognitive deficiency and mood stabilization, espeically for patients who have responded to gabapentinoids.