Diabetes mellitus (DM) is highly prevalent, and a significant public health problem. Approximately 25-30% of all individuals with DM develop painful diabetic neuropathy (PDN). PDN is considered a complex, multi-dimensional condition, possibly affecting the physical and mental health of the individual. PDN is usually described as a sense of burning, stabbing, aching and/or pricking mainly affecting areas like toes, legs, and feet and physically interfering with mobility, sleep, mood, and overall quality of life. This condition represents both a significant problem in its own right and a useful condition in which to test treatments that may offer wider benefits for neuropathic pain conditions in general.

A relatively new and promising approach to chronic pain, within the wider range of cognitive and behavioural approaches, is Acceptance and Commitment Therapy (ACT). ACT is a form of Cognitive Behavioural Therapy (CBT) that focuses specifically on increasing psychological flexibility. Psychological flexibility is the capacity to change or continue with a behaviour, depending on which is more effective, according to one's goals and what the current situation affords. Psychological flexibility in turn includes processes of acceptance, values-based action, and other processes related to mindfulness. There are no published studies of ACT for individuals with PDN, and the limited available evidence indicates that a CBT-based intervention like ACT has the potential to reduce pain in people with PDN. People with PDN have clear treatment needs. While ACT may help them, little is known directly about the relevance of different components of ACT for this condition or about how to customise it for them. The proposed research aims to conduct a small feasibility trial which will pilot test a psychological treatment for PDN and assess the feasibility, acceptability and effectiveness of such a treatment.

People with diabetes often experience a type of pain called Painful Diabetic Neuropathy (PDN). PDN is described as a stabbing, burning, pricking, or aching sensation affecting the toes, feet, and legs. This type of pain can interfere with walking, sleep, mood and overall quality of life. Although medication may offer some short-term improvement in this pain, this is a chronic condition for the majority of the patients and the pain typically remains a problem. Our research team aims to assess the acceptability and potential benefits of a psychological treatment for people with PDN.

The intervention is a tailored ACT-based self-management intervention which will be delivered online. The purpose of this intervention is to improve participant daily functioning via increased psychological flexibility. The development of the PDN ACT-based intervention involved a multidisciplinary team of psychologists, health professionals and diabetes specialists.

The ACT treatment package will embrace the core treatment processes of acceptance, cognitive defusion, mindfulness, and values-based action. Methods will include practice in contacting painful experiences, experiential cognitive methods to promote awareness, exercises similar to mindfulness, methods to increase one's the role of goals and values in patient choice, and to help people flexibly stick to commitments.

The process will involve, two brief direct one-to-one contact sessions, one at the beginning and one at the end of the intervention, with convenient means according to each participant, as for example Skype, phone or face to face. Following the first one-to-one session there will be 8 short online sessions, with a duration of 20-30 minutes each. In accordance with ACT principles, participants will be encouraged to complete tasks between the online sessions. Particularly, they will be asked to write on a diary weekly, which will include ratings for openness, awareness and engagement. Within the diary we will also ask participants to note changes, in medication, if any, and if the data is sufficient and relevant we will include them in the final analysis. The completion of these tasks has been found to be predictive of CBT outcomes.

Inclusion Criteria:

• Aged at least 18 years.
• Confirmed diagnosis of diabetes.
• Presence of painful diabetic neuropathy.
• Have full verbal and written proficiency in English.
• Willingness and ability to take part.
• Have computer literacy.

Exclusion Criteria:

• Not understanding verbal explanation or written information in English.
• Suffering from neuropathy due to other causes than diabetes.

King's College London (KCL) and Guy's and St Thomas' NHS Foundation trust (GSTT) are the co-sponsors for this study based in the United Kingdom. They will be using information from participants in order to undertake this study and will act as the data controller for this study. This means that they are responsible for looking after participants' information and using it properly. King's College London and Guy's and St Thomas' NHS Foundation trust will keep identifiable information about participants for 7 years after the study has finished. Participants rights to access, change or move information are limited, as KCL and GSTT need to manage participants information in specific ways in order for the research to be reliable and accurate. If participants withdraw from the study, KCL and GSTT will keep the information about them that have already been obtained. To safeguard participants rights, KCL and GSTT will use the minimum personally-identifiable information possible.