Throughout his career, including 35 years at the NIMH, and 20 of those as Chief of the Biological Psychiatry Branch, Dr. Post has focused on bettering the understanding and treatment of refractory unipolar and bipolar illness. He founded the International Stanley Foundation Bipolar Network (now the Bipolar Collaborative Network). Currently, he is in private practice and attempting to address childhood-onset bipolar illness.

Dr. Post helped pioneer the use of the anticonvulsant carbamazepine as treatment for lithium-resistant patients with bipolar disorder. Prior to leaving the NIMH, he and his group were exploring nonconvulsive brain stimulation with repetitive transcranial magnetic stimulation (rTMS) for treatment of unipolar and bipolar depression. Animal studies have enabled him to re-conceptualize affective illness recurrence and evolution at the level of cyclic alterations in gene expression. These views emphasize the importance of early, long-term treatment of mood disorders to prevent progressively increasing vulnerability to episode recurrence, cycle acceleration and treatment resistance.