Meet our experts

The Positive team thrives on differences: we have a wide range of working backgrounds and a huge breadth of experience. But there is one thing we all have in common: a passion for harnessing science to help people get the best from their brains.

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Positive Team

Dr Brian Marien

Co-Founder and Chairman

Brian started in medicine and then became fascinated by health, cognitive and behavioural psychology. He worked as a specialist in the Academic Department of Psychological Medicine at St. Bartholomew’s Hospital, before co-founding Positive.

Will Marien

Co-Founder and Chief Executive Officer

Will is passionate about workplace mental health and performance, and specialises in organisational behaviour change. He’s spent the last 10 years working across multiple sectors, transforming behaviours and culture in SMEs, corporates, schools and universities.

Hattie Crosthwaite Eyre

Chief Operating Officer

Hattie is fascinated by human psychology and how we can get the best from our brains. She has a 1st class degree in Human Sciences from Oxford and an MSc in Public Health. She was an Engagement Manager at McKinsey, then COO at psychology start-up Potentialife.

Dr Sinéad Devine-French

Chief Product Officer

Sinead loves empowering people to think, feel and be at their best. She’s a chartered psychologist, with a wealth of experience across private, statutory and educational sectors. She has a strong interest in cognitive and behavioural approaches for sustainable change.

Dr Catherine Marshall

Delivery Director

Catherine has a clinical and academic background, having worked as both a forensic psychiatrist and university lecturer. At Positive, she combines her experience and scientific knowledge to deliver engaging and thought-provoking sessions to clients across industries.

Dr Eloise Crush

Research Director

Eloise spent the first 10 years of her career in corporate banking and management consultancy roles, before returning to her passion: psychology. Her PhD focused on psychological resilience, and she specialises in protective factors for psychological wellbeing.

Dr Alice Gee

Client Team

Alice is a Clinical Psychologist. She worked in NHS psychological services for ten years before setting up in private practice. She has a wealth of experience in the application of psychological approaches for organisations to improve wellbeing, resilience and performance.

Dr Sophia Seltzer-Eade

Client Team

Sophia is a Clinical Psychologist. She’s trained in a number of evidence-based psychological approaches, with a special interest in Cognitive Behavioural Therapy (CBT). She’s worked in a variety of clinical and business settings, and with client groups across the lifespan.

Interested in joining our team?

We're often on the look out for passionate individuals, so take a look at our careers section for open positions.

Scientific Advisory Board

Professor Tom Sensky

Department of Psychological Medicine at Imperial College London

Professor Trudie Chalder

Cognitive Behavioural Psychotherapy at Kings College London

Professor Paul Brown

Faculty of Organisational Neuroscience at Monarch Business School

Geoff Bird

Experimental Psychology at Unversity of Oxford

Business Advisory Board

Alastair Aird

Global Chairman at Wavemaker

Robert Howshall

Head of Product at LOQBOX

Ben Churchill

Chief Strategy Officer at Cool Planet Group

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