Why hypnosis works better for some people than others

Hypnosis works better for some people because people differ in hypnotizability: how strongly they respond to hypnotic suggestions. Most people sit in the middle, a minority respond strongly, and a minority barely respond.^[1] The trait is fairly stable over decades.^[9] But it explains only part of who benefits, so a low score does not mean hypnosis cannot help you.^[14]

What is hypnotizability?

The American Psychological Association’s hypnosis division defines it as “an individual’s ability to experience suggested alterations in physiology, sensations, emotions, thoughts, or behavior during hypnosis.”^[1][2] Put simply: when a voice suggests your arm feels light, does it actually feel light, and does it rise without effort?

Two researchers who reviewed the field call this variation between people the most well-established finding from decades of experimental hypnosis research.^[3]

How is it measured?

• Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). A test of 12 suggestions, and your score is how many you pass. It is the most commonly used measure, and scores are similar across language versions.^[4][5]
• Harvard Group Scale, Form A (HGSHS:A). A group version used to screen people for research. It takes over an hour, which is why German researchers proposed a 5-item short form.^[6][7]
• Newer scales. The Sussex-Waterloo Scale adds ratings of what people actually experienced, not only what they did.^[8]

These tests have limits. A 2021 review argued that pass-or-fail scoring throws away information and that the standard scales have outlived their usefulness for current research.^[3]

How many people are highly hypnotizable?

A 2025 paper summarizes the usual picture: about 10–15% of people are high (they pass all or most items), 70–80% are medium, and 10–15% are low (they pass none or only a few).^[1] A UK sample of the Harvard scale gave a similar spread to earlier Western studies.^[7]

Treat those percentages loosely. Scores fall along a range, and researchers commonly label the top and bottom 10–15% of scorers as “high” and “low.”^[8] So the size of each group partly reflects where the lines are drawn.

Does it change over your life?

Not much in adulthood. Stanford researchers retested 50 people who were first tested as students between 1958 and 1962. The correlations between scores were .64 after 10 years, .82 after 15 years and .71 after 25 years. The median person’s score moved by only 1 point on the 12-item scale.^[9] The authors said this stability compares well with other measures of individual differences.

What is different in the brain?

A 2012 Stanford study scanned 12 highly and 12 low hypnotizable adults at rest. High scorers had stronger functional connectivity between the left dorsolateral prefrontal cortex, a region involved in executive control, and the salience network, which includes the dorsal anterior cingulate cortex. These differences were not explained by brain structure in those regions.^[10] That is a small study, so read it as a lead, not a brain test. For what changes during a session, see what happens in your brain during hypnosis.

Can you become more hypnotizable?

Training helps, but less than early studies suggested. In a 1986 study, low and medium scorers were taught strategies for responding, practiced, and watched a model respond. Afterwards, over half of the low scorers and over two-thirds of the medium scorers scored as high.^[11]

Later work was more cautious. When trained low scorers were asked to report honestly, their scores were lower, which suggests part of the gain came from trying to please the experimenter.^[12] Another study found that gains went along with more use of imagination.^[13]

Does low hypnotizability mean hypnosis won’t help?

Not necessarily. It depends on the goal:

• Pain from direct suggestion. In 85 lab pain studies, high scorers got a 42% clinically meaningful reduction in pain and medium scorers 29%. Low scorers gained little.^[15]
• Clinical outcomes overall. In a meta-analysis of 10 clinical studies, hypnotizability explained about 6% of the variation in results. The authors questioned whether testing it in clinics is worth it.^[14] Other reviews found stronger links, with correlations from 0.31 to 0.53.^[16]

So hypnotizability tilts the odds. It does not decide them. For which conditions have good evidence, see does hypnosis work?

What to do if hypnosis doesn’t seem to work on you

• Judge the outcome, not the feeling. Many people expect to feel “under.” Track the thing you want to change, such as time to fall asleep, instead of how deep the session felt.
• Give it several sessions. See how often to practice hypnosis.
• Imagine along actively. In one training study, the people whose responses improved most were also the ones using their imagination more.^[13]
• Make the goal specific. A vague goal gives the session nothing clear to suggest. See how to write a session goal.
• Switch to what has better evidence if it still does nothing. For insomnia that is CBT-I. For anxiety disorders it is CBT. Hypnosis is optional, not the only route.

Hypnova writes hypnosis sessions around your goal. It is a wellness app, and none of the studies above tested it.

Frequently asked questions