How Placebo Effects Work to Change Our Biology & Psychology

Added: Mar 4, 2024

Placebo Effects

Placebo effects occur when an inert substance or treatment that should have no biological or psychological effect actually improves symptoms or performance. These effects are not just psychological but can change the physiology of the body. The prefrontal cortex, located behind the forehead, plays a crucial role in generating expectations that can influence heart rate, blood pressure, and the release of neurotransmitters like dopamine and adrenaline.

Nocebo Effects

Nocebo effects are the opposite of Placebo effects, where a drug or treatment that should have no effect actually worsens symptoms or performance. While Placebo effects are more commonly discussed, Nocebo effects are also important to consider in understanding the impact of expectations on the body.

Belief Effects

Belief effects occur when specific knowledge or information changes expectations about a treatment or intervention, leading to a specific outcome. These effects can influence physiological and psychological processes based on the beliefs and expectations of an individual.

Specific Examples

One example of Placebo effects is the ability of a placebo drug to increase dopamine levels in the brain of Parkinson's patients, even though the drug itself does not directly impact dopamine. This illustrates the power of expectations in influencing biological functions. Another study showed that learning about growth hormone and cortisol led to changes in hormone levels in the body, even when subjects were given a placebo injection of saline.

Specificity of Placebo Effects

The specificity of placebo effects is highlighted in studies where subjects experienced changes in hormone levels based on their expectations, regardless of the actual substance they were given. Even when subjects were told they would receive a drug with opposite effects, they still experienced the same changes in hormone levels. This demonstrates the strong influence of expectations on physiological responses.

Biological Underpinnings

Placebo effects are mediated by the prefrontal cortex, which evaluates context, memories, and goals to generate expectations. These expectations can activate neural circuits that control basic physiological functions like heart rate, blood pressure, and body temperature. The brain's ability to form expectations based on information and beliefs can lead to significant changes in the body's functioning.

The Role of Context in Shaping Placebo Effect

Huberman emphasizes the role of context in shaping the placebo effect. He explains that factors such as the appearance of a pill, the color of a drug, and the level of invasiveness of a treatment can all impact the strength of the placebo effect. For example, a branded placebo pill may have a stronger effect than a generic one, and the color of a pill can influence the type of response it elicits. Additionally, more invasive treatments like injections or medical devices can lead to greater placebo effects.

Limitations of the Placebo Effect

While the placebo effect can be powerful, it has its limitations. Huberman discusses studies that show how placebos can improve symptoms like pain or discomfort, but they cannot directly impact conditions like cancer or asthma. In the case of cancer, placebos can help reduce the side effects of treatments but cannot shrink tumors. Similarly, in asthma patients, placebos can alleviate discomfort but do not improve breathing patterns.

Case Study with Nicotin

Huberman describes a study where participants were given nicotine but were told they received different concentrations of the drug. The group that believed they received a higher concentration of nicotine performed better on a cognitive task compared to those who believed they received a lower concentration. This study shows that the placebo effect is related to expectations and can influence cognitive performance.

Belief Effects and Mindsets

Huberman discusses studies by Dr. Alia Crum, who explores belief effects and mindsets. In one study, hotel service workers were told that their daily activities were either exercise or just important work. Those who believed their work was exercise experienced health improvements, demonstrating the impact of beliefs on physiological responses.

Neural Pathways and Biological Substrate

Huberman explains that the prefrontal cortex plays a crucial role in setting expectations and beliefs. Specific neural pathways connect the prefrontal cortex to regions like the hypothalamus, which control stress responses. Genes like the CT gene, which regulates dopamine and other neurotransmitters, can influence an individual's susceptibility to the placebo effect.

Implications of Placebo Effects

Understanding the placebo effect has implications for various health conditions and treatments. It can influence hormone levels, pain perception, and even muscle growth. By harnessing the power of belief and expectation, individuals may experience positive changes in their health and well-being.