
Dr. Cerith Waters
Cerith is a consultant clinical psychologist working within a Specialist Perinatal Mental Health Services in Cardiff and Vale UHB, Wales, UK. He is also the Research Director for the Doctorate in Clinical Psychology at Cardiff University.
Cerith was the creator of the ACT-PNMH intervention in it’s original format of face-to-face group delivery. His journey into ACT started in 2008, when he was completing his PhD and working on a study evaluating the acceptability and effectiveness of CBT and Mindfulness for adult OCD. Cerith has also worked on an innovative evaluation of a pilot service offering a brief ACT intervention to NHS staff, which to the surprise of many, found a significant reduction in psychological distress and sickness absence at 3 months post-treatment.
During clinical training, Cerith sought opportunities to learn and practice ACT. His DCLIN thesis focused on designing a trial evaluating the efficacy of ACT for NHS staff experiencing psychological distress. And upon qualifying, he sought opportunities to merge his interests in perinatal mental health and ACT. In 2014 this ambition was born as he co-led on the set up of the perinatal community mental health service in Cardiff. Cerith then developed the original ACT-PNMH intervention within this perinatal setting, and he has regularly used ACT ever since. Cerith also provides training and supervision to colleagues on using ACT within the area of perinatal mental health. Cerith continues to be involved in evaluations of ACT-PNMH, publishing research papers demonstrating its use for perinatal populations, as he has a passion to show its helpfulness in this area.
Cerith enjoys being in nature as much as possible, particularly at the seaside or climbing mountains. Watching rugby is also a passion of Cerith’s, as is cooking new dishes and growing vegetables.

Claire Traylor
Claire is a Mental Health Nurse, with over 29 years of experience working with the NHS in Wales, UK. Claire has been working in perinatal mental health services for over 10 years, and first learnt about ACT when moving from adult acute in-patient services, to the perinatal service. Claire met Cerith, and supported the delivery of ACT as a group within this setting in 2014, and was one of the first facilitators and continues to be a key facilitator and co-ordinator of the groups running within Cardiff! Claire, like Cerith, has engaged in further training in ACT, reading many books, and ACT has become one of her main models of psychological intervention in her professional work.
Claire also works as a trainer within our team, training teams in using ACT within the area of perinatal nationally and internationally, and has supervised many of the teams who have gone through our ‘train the trainer’ programme to deliver ACT within their service contexts. One of Claire’s many hidden talents is her ability to create metaphors, branding her as the ‘metaphor queen’.
Away from work, Claire enjoys slowing down by the seaside at her static caravan. She loves reading across a wide range of genres, from fiction to ACT based books as she enjoys learning as much as escapism. She loves music, live concerts, and the theatre, and particularly value sharing these experiences with her teenagers.

Dr. Jennifer Berrett
Jenny is a Highly Specialist Clinical Psychologist, working within Maternity Psychology in Cardiff and Vale UHB, Wales, UK. Jenny also works as a research associate and lecturer within Cardiff University. In 2014, whilst working as a research psychology assistant for Cardiff University, Jenny discovered ACT through adult learning classes, and from then on, has taken on further training and continues to use it as a main model to draw on in psychological interventions provided. Jenny joined the Cardiff and Vale Perinatal Mental Health Service in 2019, where she facilitated the face-to-face ACT intervention. Since returning from maternity leave in 2020, Jenny has supported the delivery and adaptation of the group ACT intervention for remote-delivery. Jenny now provides training and supervision in using ACT within different service contexts, and has been involved in the cultural adaptation of ACT internationally.
In her NHS role, Jenny is currently leading on a pilot of using ACT for Pregnancy-After-Loss, a 10 week group adapted from the original ACT-for-Perinatal Mental Health. Two groups have been piloted so far, and the findings are promising, particularly around increased psychological flexibility.
Due to Jenny’s own experience of Hyperemesis Gravidarum (HG), she has both a personal and professional interest in HG, and using ACT with presentations related to HG. This led her to work privately, to support those who have experienced HG and has found ACT to be helpful in targeting the secondary suffering that comes with this.
Jenny enjoys winter walks with hot chocolate, being near the sea, exercising, a good comedy, musical theatre shows, travelling to new places (with a good book!) and trying new foods.