A neuroscientist's view on how hypnotherapy works

The human brain is an extraordinary organ. As a neuroscientist with a background in psychology, I have spent years studying the factors that drive human behaviour and shape the patterns we find hardest to shift. It was that same fascination with how the brain changes that eventually led me to train as a clinical hypnotherapist.

In recent years, neuroscience research has considerably advanced our understanding of neuroplasticity – the brain's remarkable ability to reorganise itself through experience, repeated thought, and behaviour. Hypnotherapy is one therapeutic approach that works directly with this capacity. It was during my hypnotherapy training that I began to explore what is actually happening at a neural level during and after a hypnotherapy session.

This article is for anyone curious about that intersection – where neuroscience meets therapeutic practice.

Understanding hypnotherapy

Despite what television and stage hypnosis might suggest, hypnotherapy has nothing to do with surrendering control or falling under anyone's spell. What it actually involves is a focused, relaxed brain state in which our attention turns inward and the analytical mind quietens down.

In that state, it becomes easier to access processes that sit below conscious awareness – what is often referred to as the subconscious. From there, we can begin working with automatic thought patterns, emotional responses, and habitual behaviour that may no longer be serving us.

The neuroscience behind hypnotherapy

Hypnotherapy can be understood as a way of working with the brain's natural capacity for focused attention and learning. Three things happen neurologically during hypnosis that are worth understanding:

1. The default mode network becomes less active

The Default Mode Network is the part of the brain that tends to be active during low-demand conditions such as daydreaming, mind-wandering, or replaying the same worry for the tenth time. During hypnosis, activity in this network decreases (1). The internal chatter settles, and attention becomes more focused and inwardly directed. It is this quieter mental space that creates the conditions for new insights, neural connections, and awareness to emerge.

2. Increased theta wave activity

Research has shown that hypnosis is associated with increased theta brain wave activity (2) – the same pattern seen in deep meditation and REM sleep. In these states, the mind tends to be open, creative, and emotionally receptive. This may be one reason why therapeutic suggestions made during hypnotherapy tend to land differently than the same words spoken in ordinary conversation. In a theta state, they appear to reach the brain before the habitual filters of doubt and self-editing have a chance to intervene.

3. Toward a more regulated nervous system

During hypnosis, the amygdala, our brain's threat-detection system, becomes less reactive, which helps allow the nervous system to settle. At the same time, the prefrontal cortex, which is involved in insight, learning, and decision-making, becomes more engaged. This combination creates a state in which it becomes possible to look at old patterns with some clarity rather than defensiveness, and to begin building new responses in their place.

Why patterns keep us stuck, and what shifts them

Most of the patterns that keep people stuck are not logical. They are learned and formed through earlier experiences, emotional imprints, and beliefs that became established long before conscious reasoning had much say in the matter. That is why understanding a pattern intellectually, or deciding to simply ‘think differently’, does not always change it. 

Hypnotherapy works at the level where those patterns are stored. In a relaxed, receptive state, the brain is better placed to form new neural pathways. You are not simply imagining a different response – you are rehearsing it at a neurological level. Repeated rehearsal makes new responses feel familiar. The brain loves familiarity, and what feels familiar, over time, starts to feel like the default.

The changes initiated during a hypnotherapy session are not confined to the session itself. Neuroscience research on memory consolidation suggests that the brain continues to process and stabilise new learning after the experience ends (3), which may be one reason why clients sometimes notice shifts in the days following a session rather than immediately afterwards.

Where the research points

The evidence base for hypnotherapy is continually increasing. It is used in clinical and integrative settings worldwide for a wide range of presentations: anxiety and panic, phobias, IBS and chronic pain, insomnia, trauma, confidence and performance issues, preparation for labour and birth, and habit change, including smoking cessation (4).

It is worth saying that hypnotherapy is not a uniform experience. Some people notice meaningful shifts after one or two sessions. Others need more time for things to settle and integrate. What tends to matter most is the quality of the therapeutic relationship, a sense of safety within the session, and the person's own readiness to engage with the process.

Hypnotherapy is a therapeutic tool that meets people where they are. Clients often already sense, somewhere, what needs to shift. What they need is the right internal conditions for that shift to feel safe – and that is what a well-structured hypnotherapy session can offer. The brain is extraordinarily adaptable, and when the right conditions for change are in place, even long-standing patterns can begin to shift. 

References

1. Deeley, Q., Oakley, D. A., Toone, B., Giampietro, V., Brammer, M. J., Williams, S. C. R., & Halligan, P. W. (2012). Modulating the Default Mode Network Using Hypnosis: Quinton Deeley, David A. Oakley, Brian Toone, Vincent Giampietro, Michael J. Brammer, Steven C. R. Williams, y Peter W. Halligan. International Journal of Clinical and Experimental Hypnosis, 60(2), 206–228. https://doi.org/10.1080/00207144.2012.648070
2. Jensen, M. P., Adachi, T., & Hakimian, S. (2015). Brain oscillations, hypnosis, and hypnotizability. American Journal of Clinical Hypnosis, 57(3), 230–253. https://doi.org/10.1080/00029157.2014.976786
3. Tononi, G., & Cirelli, C. (2014). Sleep and the price of plasticity: From synaptic and cellular homeostasis to memory consolidation and integration. Neuron, 81(1), 12–34. https://doi.org/10.1016/j.neuron.2013.12.025
4. Rosendahl, J., Alldredge, C. T., & Haddenhorst, A. (2024). Meta-analytic evidence on the efficacy of hypnosis for mental and somatic health issues: A 20-year perspective. Frontiers in Psychology, 14, 1330238. https://doi.org/10.3389/fpsyg.2023.1330238