i've had hashimoto's since i was 19 (46 now). been bipolar, i believe, since around the same time. hypothyroidism can cause depression, and bipolar can cause (i think) hypothyroidism (or maybe it's that some of the meds can). thyroid & mental illness can go hand in hand. i wouldn't go by symptoms for the thyroid disorder, i'd go strictly by the T3 & T4 levels. those are the only true diagnosis tools for thyroid disorder. how you FEEL might be attributed to thyroid disorder, might be mental illness - harder to tell. i'd say get the thyroid under control first, since that IS controllable. then you'll see what you're left with.
hope that helps some.