I used to get the negative thought cycle. I couldn't stop one without another one creeping in. I did alot of research into the brain and neurology because I've found that the only way out of a problem is to know it inside out. I have fought anxiety and depression for years and what finally worked with me was disempowering it with education- knowledge is power. And I just got so tired of feeling powerless against it. Whenever negative thoughts first start I don't try to stop them. That's because our brain only works in 'go' commands. Even when we tell ourselves to stop walking; certain groups of muscles are told to 'go' to make us stop. I hope that makes sense. But, getting back to negative thoughts... instead of thinking "stop these now" i use a little trick. You have to force your brain to replace them with something that is a little challenging. If your brain is 'thinking'- it's not fearing. These two parts of your brain (amygdala- for fear and cortex- for thinking) can't be on at the same time. Use your thinking brain - force it into operation- and your amygdala (fear, adrenaline, doubt, anxiety, shame,) shuts down. Try counting by 2 then 3 then 2 then 3. Like this: 2,5,7, 10, 12, 15 or something more challenging that really makes you focus on it. Whatever we focus on only becomes stronger and more pronounced. The Twelve Days of Christmas also worked for me because it made me think. Any nursery rhyme recall makes you think. Find-a-word puzzles, saying words backwards, doing hard math questions.... I know this sounds too good to be true... and I didn't believe it would work... but it did work for me. I force my brain to think myself out of negative thoughts. I hope this helps you. But, it is not as easy as it seems. At first, it's like a tug-a-war between these two centres in your brain. It also helps to hold a pen or pencil- this is automatically seen as a 'tool' to your brain and your amygdala will begin to shut down and your cortex (thinking brain) will automatically be ready to help you.