When suffering or happiness arises, changes in brain wave activity in certain parts of the brain are detected. Thus some people believe suffering and happiness are produced by the brain. Actually, the brain is only a tool. Consciousness is dependent on the brain to discern and experience external phenomena, but suffering and happiness are not produced by the brain.

The sutras have often discussed and demonstrated that suffering comes from self-attachment, that is, attachment to the existence of a self. Here, the conclusion is set forth from a different standpoint. Suffering and happiness are not produced by external circumstances, but are closely related to our views and habitual tendencies. All suffering is created by our own attachment to things.

- Quote from Are You Ready For Happiness? Don't Let the Paper Tiger Scare You Off, "How to Face Suffering"