If someone is caught in a spiral of negative thinking, what can be done? The best thing, by far, is to nip it in the bud. As you see the first storm cloud gathering in your child's face, distract! When you see a negative though creeping your way, distract! (Once the thought is through the gateway, different measures are needed, and I'm not going to get into that here.)
Charlotte Mason wrote about the power of thoughts and distracting yourself several times in her books. Perhaps in every volume, but I haven't checked. I'm currently in Vol 4 (see last week's post), and here is what seems relevant to me regarding letting in positive instead of negative ideas.
We choose between Ideas.––It is well, however, to know what it is that we choose between. Things are only signs which represent ideas. Several times a day we shall find two ideas presented to our minds; and we must make our choice upon right and reasonable grounds. The things themselves which stand for the ideas may not seem to matter much; but the choice matters. Every such exercise makes personality the stronger; while it grows the weaker for every choice we shirk. Vol 4, Bk 2, pg 146
Will, the Instrument by which we appropriate Ideas.––But there are persons who never entertain the idea that presents itself, and who, therefore, form neither intention, purpose, nor resolution upon it––the persons who do not use their Will. And there are persons who deliberately will and choose to entertain harmful and injurious ideas; the thoughts of whose hearts are only evil continually, whose purposes, resolutions, are ever towards evil ends. p. 165
The Postern to be Guarded.––The place to keep watch at, is, not the way of our particular sin, but that very narrow way, that little portal, where ideas present themselves for examination. Our falls are invariably due to the sudden presentation of ideas opposed to those which judgment and conscience, the porters at the gate, have already accepted. p.166And most obviously, here is Vol 4's best quote about changing your thoughts:
We do not struggle against, or argue down, or say bad things against the trespasser. By a conscious act of will, we simply and instantly think of something else––not something good and lofty, but something interesting, even something diverting; what we shall do on our next holiday, a story we are reading, a friend we mean to see, even a fly walking across the ceiling, is enough to think about; because any other occupation of the mind keeps out the insidious idea we would repel, and it has no power over us until it has been willingly admitted. p.168She's not the only one, though. Even Willie Nelson gets it. :)
Once you replace negative thoughts with positive ones, you'll start having positive results.
When the negative thoughts come - and they will; they come to all of us - it's not enough to just not dwell on it... You've got to replace it with a positive thought.
Do keep in mind, though, that looking for the positive side of something, or distracting yourself from something negative coming into your head, isn't the same as pretending bad things don't happen, or that you can fix the world by ignoring problems. I think some people may not know the difference...
Many persons swear by positive thinking, and quite a few have been helped by it. Nevertheless, it is not a very effective tool and can be downright harmful in some cases.
Quotes discovered via http://www.brainyquote.com/
I'll leave you with this, from Vol 4. pg 165:
We know that what we do or say matters less than what we will; for the Will is the man, and it is out of many acts of willing that our character, our personality, comes forth.