Medications that work for bipolar disorder continue to puzzle researchers, who don't yet fully understand how they do their thing — their mechanism of action. For example, although antidepressants and antianxiety medications are known to target certain neurotransmitters, this may not be their major effect in treating bipolar. Lithium and valproate (Depakote) — the primary antimanic medications — seem to operate on processes within the cell itself rather than on the transmitters between synapses.
The mechanism of action of mood medications may include any of the following activities or others still being discovered, depending on the type of medication:
Increase the levels of a particular neurotransmitter within the synapse by preventing its breakdown by enzymes or by preventing it from being sucked back into the first neuron
Change how a neuron receives a neurotransmitter — by blocking, opening, or otherwise changing the receiving cell's receptor proteins
Strengthen neuroprotective factors that help cells recover from injury and maintain healthy cell development, growth, and function
Inhibit or increase the activities of enzymes that are important to the signaling systems in neurons
Change patterns of electrochemical pulses in the neurons
Alter pathways that trigger changes in gene expression and possibly even alleviate negative environmental effects on the chemical packaging of DNA (epigenetics)