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Core Services


We can provide expert witness for victims of trauma and human rights abuses for UK, Asylum Tribunals and International Courts.

Our experts have provided expert witness in national and International cases. Civil, Criminal, Military and Family courts.



Our London based Clinical Psychologists can assist with a variety needs. We utilise evidenced based psychological therapies such as CBT. 

Click here to make an appointment with a Clinical Psychologist today at our Clinic in Clapham, London, UK

We are BUPA Approved.



Recent training includes:


Trauma and psychosis

Motivational Interviewing in Trauma

Psychological care for refugees



Criterion A Psychology Services was established to meet demand for experienced clinical psychologists to provide services to people around the world who have been or are involved with traumatic events. We provide evidence-based, psychological treatment for adults experiencing many mental health and mental wellbeing demands including PTSD, depression, anxiety, addictions and psychosis. See our Psychological Treatment Page for further information. 

We have a bank of consultants who are ready to meet your needs. We provide expert witness, training and consultation and treatment.

Criterion A Psychology Services was founded by Dr. Brock Chisholm. Dr. Chisholm has extensive experience in working with victims of trauma. He has provided expert witness to several high profile cases and has provided evidence based psychological intervention to many people suffering complex reactions to traumatic events. He is trained in EMDR, Cognitive Behaviour Therapy, Motivational Interviewing and Narrative Exposure Therapy.

Individual psychological therapy is not sufficient for many survivor’s of trauma. That is why Criterion A provides a comprehensive service and treatment packages for complicated traumatic stress reactions.

Dr. Brock Chisholm is on the list of experts for the Preventing Sexual Violence Initiative hosted by The Stabilisation Unit under the British Foreign and Commonwealth Office.

Why Criterion A? Criterion A refers to the traumatic event that can elicit a PTSD reaction. We specialise in providing solutions to people affected by traumatic events. 


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