About the "Tortured Genius" theory...

Let's use a little analogy. Let's say my body fluids, particularly my blood plasma electrolytes, being part of my 'electrical system' is like the fluid in a wet-cell battery such as you might find under the hood of your car. 

When I'm in a manic 'high', I'm overactive, underslept, talking, thinking, and acting quicker than usual, and I'm probably dehydrated. I'm like that wet-cell battery when it has been overcharged, and its fluids are partially depleted, and its voltage is above normal. It has a lot more 'snap', so things happen with less hesitation, and may last longer before running down.

When I'm in a depressive mode, I'm like a battery that's suffering from lower than normal voltage, and perhaps an excess of fluids. The car starts more slowly if at all, and the lights are dim. I think, talk, and act more slowly, move slower if at all, and I don't give a damn if it rains or freezes. 

Our 'tortured genius' can be very creative during a manic 'high' because ideas come flying out of nowhere, seemingly at twice the speed of sound; we can do things without thinking which normally would take some careful consideration;
and it's like the rest of the world around us is in slow motion. We get impatient with all these slack-asses we're expected to work with during such episodes;
and we scare the shit out of you 'normals' because you just can't keep up, and you know better than try. These manic 'highs' are better than the kind from drugs, because they're free, wonderful while they last, and we get lots done.
Unfortunately, what goes up has to come down. But there's no free lunch.

And that's one manic-depressive's interpretation of 'tortured genius'. I don't qualify, because my I.Q. is only about 131. But I can relate to the problem.
Whoever said, "When you're hot, you're hot, and when you're not, you're not" was probably bipolar, and may he or she live long and prosper.