Ketamine is a prescription-only medicine that may be prescribed off-label by our medical team following a comprehensive assessment to assist in the psychotherapy.
Ketamine is a prescription-only medicine that may be prescribed off-label by our medical team following a comprehensive assessment to assist in the psychotherapy.
THE SCIENCE
Ketamine works on multiple parts in the brain and body, re-engaging a set of receptor pathways and supporting neuroplasticity. It can help shift patterns that have people stuck in depressive, anxious, trauma and chronic states.
This evidence explains the science in clear terms and, more importantly, what these changes can mean for you.
IMPORTANT INFORMATION
This page is an educational resource. Ketamine is a prescription-only medicine in the UK. Its use in the treatment of depression and other mental health conditions is off-label — meaning it is not a licensed indication, but it is a recognised and lawful clinical practice when prescribed by an appropriately qualified clinician following thorough assessment. Nothing on this page constitutes medical advice or a recommendation for treatment. Suitability is determined through individual clinical assessment.
Ketamine’s primary action is blockade of NMDA receptors — a class of glutamate receptor involved in synaptic communication, learning and the regulation of excitatory activity in the brain. By inhibiting these receptors, ketamine alters the balance between excitatory and inhibitory signalling, triggering a downstream cascade that affects how brain regions communicate with one another.
WHAT THIS MAY MEAN FOR YOU
In depression, anxiety and chronic stress, certain neural circuits can become hyperactive and self-reinforcing — particularly those involved in rumination, threat detection and negative thinking. The changes ketamine initiates at the receptor level may temporarily reduce that hyperactivity, creating a shift in the brain’s functional state that some people describe as a quietening of persistent mental noise.
KEY POINTS
Following NMDA receptor blockade, ketamine triggers a secondary cascade involving AMPA receptor activity, increased release of brain-derived neurotrophic factor (BDNF) and the formation of new synaptic connections — a process known as synaptogenesis. These changes support neuroplasticity: the brain’s capacity to adapt, reorganise and form new patterns of activity.
WHAT THIS MAY MEAN FOR YOU
Chronic depression, trauma and persistent anxiety are associated with reduced synaptic connectivity in regions involved in mood and cognition. The neuroplastic changes ketamine may stimulate could help restore some of that flexibility — creating a period in which established patterns of thinking, feeling and responding may be more open to change than usual.
KEY POINTS
“Ketamine’s significance is not simply that it acts quickly, but that it appears to open a temporary state in which brain, mind and experience may become more receptive to change.”
— The Emerge Clinic
Ketamine does not act uniformly across the brain. Its effects are network-specific, influencing particular regions and the connections between them in ways that are relevant to mood, emotional regulation, self-perception and cognitive flexibility.
WHAT THIS MAY MEAN FOR YOU
The regions ketamine influences are precisely those most implicated in depression, trauma and anxiety. Reduced reactivity in threat-processing areas can contribute to a sense of greater calm. Changes in self-referential networks may quieten the critical inner voice. Shifts in prefrontal function may support clearer thinking and greater perspective.
KEY POINTS
Prefrontal Cortex
Supports cognitive control, insight and the capacity to reflect rather than react
Amygdala
Reduced fear reactivity and hypervigilance.
Hippocampus
Improved context for memory and emotional regulation.
Anterior Cingulate Cortex
Better error detection, motivation and emotional regulation.
Default Mode Network
Reduced self-referential thinking and rumination.
Alongside its primary glutamatergic effects, ketamine influences monoamine systems including dopamine, serotonin and opioidergic pathways. These effects are generally indirect and unfold over a different timescale to the immediate NMDA receptor action. Dopaminergic activity in particular is associated with reward processing, motivation and the capacity to experience pleasure — functions that are frequently disrupted in depression.
WHAT THIS MAY MEAN FOR YOU
One of the most debilitating features of depression is anhedonia — the loss of interest or pleasure in things that previously felt meaningful. The monoamine effects of ketamine may contribute to early improvements in motivation, emotional engagement and reward sensitivity, though these changes vary between individuals and are not guaranteed.
KEY POINTS
Chronic stress and persistent depression are associated with elevated neuroinflammation — an activation of immune-related processes within the brain that can interfere with neuroplasticity, synaptic function and mood regulation. Ketamine interacts with several inflammatory and stress-response pathways, and there is growing evidence that it may reduce markers of neuroinflammation in some individuals, though this remains an area of active research.
WHAT THIS MAY MEAN FOR YOU
For people whose difficulties have a significant stress or trauma history, inflammatory processes may be part of what sustains their symptoms. Ketamine’s potential anti-inflammatory effects could contribute to an improvement in mood, energy and cognitive clarity — though individual response varies and this mechanism is less well established than the glutamatergic effects described in earlier sections.
KEY POINTS
The neuroplastic window that ketamine may open does not produce change on its own. What happens within that window – the psychological work done before, during and after treatment – is central to whether the shift in the brain’s functional state translates into lasting therapeutic benefit.
This is the clinical rationale for ketamine-assisted psychotherapy as a model rather than ketamine as a standalone medical intervention
WHAT THIS MAY MEAN FOR YOU
The period following a ketamine session may be one in which long-standing patterns of thinking, relating and responding are temporarily more accessible and more open to examination. Psychotherapy during this period is not an add-on – it is an attempt to make meaningful use of a biological state that would otherwise pass without being fully utilised.
KEY POINTS
FROM RECEPTOR TO PSYCHOLOGICAL CHANGE: A CONCEPTUAL PATHWAY
Ketamine Session
Medically supervised treatment within a structured clinical programme
Neurochemical Shift
Changes in receptor activity, glutamate signalling and synaptic communication
Neuroplasticity
Increased synaptic connectivity and network flexibility
Functional Change
Shifts in mood, emotional regulation and cognitive flexibility
Therapeutic Opportunity
Psychotherapy and lifestyle changes help with healing
This is a conceptual model of a complex biological process. Individual response varies – not everyone will experience each stage in the same way or to the same degree.
“When the brain becomes more flexible, psychotherapy can reach deeper. Change is not forced — it’s allowed.”
— The Emerge Clinic
THE BOTTOM LINE
Ketamine acts across multiple biological systems simultaneously — not through a single pathway but through a cascade of neurochemical, structural and network-level changes. The science does not support a simple mechanism. It supports a complex one, which is why treatment requires careful clinical management rather than a formulaic approach.
The most meaningful and durable change is most likely to occur when the biological effects of ketamine are met with structured psychotherapeutic work — before, during and after treatment.
FURTHER READING
IN THIS SERIES
The Research
What the evidence tells us
The Journey
Ketamine’s journey from anaesthesia to psychiatry
Personalised Ketamine Science
What may respond, how we tailor it
Psychology & Personal Insight
Working together in medication
Risk & Safety
Safe, ethical care and continuity
This page does not constitute medical advice. Ketamine is a prescription-only medicine in the UK and its use in mental health treatment requires thorough individual assessment by a qualified clinician. The science described here informs our approach – it does not determine suitability for any individual. If you would like to discuss whether ketamine-assisted psychotherapy may be appropriate for you, the first step is a confidential conversation with the team.