A dog with mental problem? ROFL! Sounds like a lot of people I know...

You don't mention the age, size, weight or breed of the dog...could you give us some more information. Also, what TYPES of collars and products were used on your dog? How old was the dog WHEN YOU GOT HIM...and WHERE did you get him? Does he have any other training issues? House training? Sit, come, stay, lay down...will he, can he...do these behaviors? How much exercise does he get on a daily or weekly basis? This would help with figuring out exactly what the problem is. Be aware there ARE dogs (often from Pet Stores/Puppy Mills...) who really ARE mentally and emotionally unable to learn...they would be called "Crazy" if they were humans, because their brains DO NOT function normally at all...It's not the dog's fault...it's the breeding...and sometimes the circumstances they were in. If your dog CAN LEARN...has learned to ask and go potty outside...can sit on command...comes when you call MOST OF THE TIME...is able to relax with you at times...then this can be related to the amount of exercise he NORMALLY is getting, and how the lesson of not pulling was being given to him. I do feel, that if the dog (or any animal) is not mentally challenged (in a crazy way) that it is up to the trainer to figure out what will stimulate and captivate the dog to WANT TO LEARN...we have to reward them in a way that MAKES SENSE to the dog.