Dispenza defines the nocebo effect as the negative counterpart to the placebo effect, where belief in harm or illness leads to real physiological decline. He argues that negative expectations—such as a dire medical diagnosis or societal conditioning about aging—can trigger stress responses, weaken the immune system, and even cause disease. According to Dispenza, just as belief in healing can create health, belief in illness can manifest suffering, reinforcing his idea that thoughts alone have the power to shape physical reality.

Dispenza defines mental rehearsal as the practice of vividly imagining a desired outcome until the brain and body respond as if it were real. He argues that mental imagery activates the same neural pathways as actual experience, allowing individuals to train their minds and bodies for healing, success, or transformation. According to Dispenza, mental rehearsal—especially when combined with strong positive emotions like gratitude or joy—can rewire the brain, influence gene expression, and create real physiological change.

Dispenza defines suggestibility as the state of being highly receptive to new beliefs, thoughts, or experiences, particularly when the analytical mind is relaxed. He argues that entering lower brain-wave states, such as alpha and theta, increases suggestibility, making it easier to reprogram subconscious beliefs and initiate physiological changes. According to Dispenza, highly suggestible individuals can harness this state through meditation and visualization to heal illnesses, alter behaviors, and reshape their reality, reinforcing his idea that deep mental focus and belief can override biological limitations.