Another class of drugs that has shown efficacy in preventing migraine and treating depression are the tricyclic antidepressants (TCAs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), which can potentiate the actions of serotonin and norepinephrine action by inhibiting reuptake via their respective transporters, the serotonin transporter (SERT) and the norepinephrine transporter (NET). This evidence concerns the gene SLC6A4 and depressive disorder.