i had had a goiter as a teenager and the radiation they used to shrink the thyroid actually was too high a doseage. when i went into the hospital to get help for what later was diagnosed, among many things, bipolar. the pdoc first ran a thyroid test. as it turned out now my thyroid was under-performing and it contributed to the depression i experienced. was very fortunate to have a pdoc that checked this right away. now take synthroid to balance me out. and yes the t 3 and t 4 are necessary to really get a good profile of the thyroid.
hope this helps.