Why do I always smoke during my manic episodes?

Risk Assessment. One of the key things that happens with mania is that the part of the brain that keeps watch for risky situations is shut down. This means that you truly don't see potential risks when manic, which is also most of why mania is so dangerous.
Calming effect. Nicotine (smoking) xauses release of Dopamine and activation of gaba receptors which has a calming effect. Before trying to cut down smoking control of mood with mood stabilizers is of paramount importance.