Lithium blocks the sodium-dependent multivitamin transporter. See Figure 2 E. The sodium-dependent multivitamin transporter (SMVT) transports pantothenate, biotin and lipoate. I have previously argued that pantothenate is involved in mania and negative symptoms. Lithium by blocking the SMVT would decrease transport of pantothenate and decrease mania. If this idea is correct treating bipolar disorder with lithium, which blocks other sodium-dependent transporters and has myriad other effects, would be equivalent to using a kilogram of plastique to kill a fly. Biotin via biotinylation decreases transcription of the the gene for the SMVT. Other supplements besides biotin are in all probability required to treat bipolar disorders. Biotin could be effective for the manic phase of bipolar disorder but would do zip and could even worsen the down phase of bipolar disorder.