I have a friend who, by his own definition, is overweight and has a problem with food. He uses food to cope. Food is his comfort and his control device (among other things).
He has a job that at times can be high stress. When this happens, he'll feel run down and tired and in need of an energy boost. This is likely, if not definitely, due to his overeating and poor health. But it occurs during periods of high stress, so that triggers the need to control the situation, and to do so, he turns to his favorite food.
He loves brownies. He can eat an entire box of Little Debbie frosted brownies in a sitting. He often finds himself wanting brownies when things get tough. "I am tired and run down," he says to himself. "I need a brownie." He looks around the office -- there are no brownies. "I could get up and go to the store and get some brownies..."
There they are: two lies, back to back. He's tired and run down, and it has to be because of stress, and a brownie will fix it. But there's no brownies, and suddenly he has the energy to run to the store and get brownies.
That's how you know Sick You is trying to get control. Sick You tells you whatever you need to hear, moment to moment, to get you what you think you want. It will change its story to adapt to any argument you come up with. It is a liar. It is a conman. And the greatest con that it pulls is making you think that it is you.
But it's a voice in your head, right? So it must be you.
But it's not. It's Sick You. It's the worst part of your Ego. Not "ego" as in the pejorative we use to describe someone's thoughts about how great they are. This isn't "ego" as in "egotistical," this is Ego. Defining from the link above, the Ego comprises the organized part of the personality structure that includes defensive, perceptual, intellectual-cognitive, and executive functions.
In short, it's the rider on your horse. It's the pilot of your airplane. It has to use its strength and every trick in the book to control the much stronger, much more dangerous, much more powerful vehicle that is you.
Another friend of mine is an alcoholic. He described his conman's discussion with himself:
Take a drink. You need a drink. You're right, you don't need a drink. You just want one, so let's prove you don't need it. Yeah, see? You don't need it. You just want it. You deserve a drink for that.
The greatest opponents hide in places you will never think to look. Your Ego hides behind pain. "This will cause you pain," the Ego says to you. "Fight against the pain." It wields pain as a shield. It convinces you that, if you realize you are at fault for something terrible, or if you back down from a challenge, or if you face a consequence, it will hurt. So justifications kick in. Stories you tell yourself. You cast yourself as the hero in your own epic novel. You can't be wrong. Whatever it is you did, there's a really good reason for it.
Sick You gains control.
These interviews with world renown psychiatrists sums Ego up very nicely:
"The greatest con [the Ego] ever pulled, is making you believe it is you."
Sick You pulls this con every single day, day after day. And it's a liar. It'll tell you multiple lies, one after another, to help you avoid pain. To keep you from hurting. To keep "you" in control. It's your failsafe. It's your steam release valve. It's your pilot. But it's NOT you.
Next time you hear yourself talking to you in your mind, listen to what is being said. If it's drive is to avoid pain -- the pain of withdrawals, the pain of sadness, the pain of loneliness, the pain of the moment... Ask who it is that's speaking. Start THAT dialog. The more it hurts, the more likely it is that Sick You is trying to take control.
(If you're interested in giving Revolver a try, I highly recommend watching this clip series, which sums up the metaphor very neatly without giving away the ending of the film.)