When a person's mind is going at a speed which is faster or at a speed which is slower than it ought to be, or if a person jumps from one thought to another and so goes on thinking of a thousand things in five minutes, however intellectual he may be, he cannot be normal. Or if a person holds one thought and broods on it instead of making progress, he will also cling to his depression, his fears, his disappointments, and that makes him ill. It is irregularity of the rhythm of mind which causes mental disorder.