Neuroprotective or Pointless? Conflicting evidence on Lithium's role in the pre-frontal cortex
Although there is limited data on the role of Lithium (Li) on the human nervous system, a 2012 paper revealed that bipolar patients undergoing Lithium treatment had similar levels of N-Acetylaspartic acid (NAA, an important amino acid in the brain) in the pre-frontal cortex than controls, while patients not treated with Lithium had lower levels of NAA; thus suggesting Li to have neuroprotective effects. At the same time, however, another study showed no significant increases in NAA levels of the prefrontal cortex after Lithium administration, so there is no clear answer.
Lithium has not shown to alter the volume or number of neurons in the pre-frontal cortex when studied in mice, or in humans; However, another study (2009) revealed that Lithium did significantly increase prefrontal cortex size in healthy humans. Again, no known answer.
It has shown to increase grey matter (i.e, brain tissue) size in the prefrontal cortex in Bipolar Disorder (BD) patients. At the same time, it has shown to have no effect on the grey matter of Severe Mood Dysregulation (SMD) patients, so the data is quite unclear at the moment.
Regarding neurotransmitters, Li has shown to increase the concentrations of serotonin (responsible for pleasure) in the pre-frontal cortex when administered with antidepressants. It has also shown to increase the concentration of glutamate (an excitatory neurotransmitter) in the prefrontal cortex of rats.
In all, this is a very difficult question to answer with minimal research, largely yielding inconsistent results at the moment. Nevetheless, although the data is conflicting, it is largely suggested that Lithium has the potential to treat mood disorders and promote the survival and growth of neurons in the brain. This largely suggests that, in order to fully elucidate whether Lithium is a potential target for neuroprotection, more and a greater variety of studies are required to confirm its effects on the brain.