The study aims to explore whether an online compassion-based guided self-help intervention is perceived as acceptable to people with heterogeneous skin conditions, in terms of retention rates and explicit feedback. The study also aims to investigate the feasibility of providing online compassion-based self-help and email guidance. Changes in depression, self-compassion and skin-related distress will be assessed to give an estimate of likely effect sizes for future research

The study will investigate an online compassion-based self-help intervention with email guidance with people with skin conditions who are experiencing depressive symptoms. As the study aims to investigate a novel intervention, the study will be an acceptability and feasibility study that uses a pre-post design. Participants with skin conditions will be recruited from the general population using online methods (social media and advertisements on skin condition charities/organisations websites). Participants will complete baseline measures using Qualtrics and then be able to commence a six-week online intervention, consisting of a dedicated website containing six self-help sessions to work through. Regular guidance will be provided by the researcher via email. The self-help exercises in the current study will consist of a number of exercises derived from Compassion Focused Therapy (CFT)/Compassionate Mind Training, such as using soothing rhythm breathing, compassionate imagery and compassionate writing. Explicit feedback will be sought from participants at the end of each session, and at the end of the intervention overall. Engagement with the website will be monitored via user logins and this will be used to calculate the retention rate for the intervention. Post-intervention measures will be collected one week after the end of the intervention. All participants will be provided with signposting information relating to mental health and skin conditions, and advised to see their GP if they require any further support with their physical or mental health.

Intervention The guided self-help intervention will consist of six online sessions of self-help information for participants to work through, plus activities to carry out in-between sessions. The intervention will consist of psycho-education material, self-monitoring, and compassion-inducing exercises from CFT. The self-help exercises in the intervention will be evidence-based as being effective for depression: the compassion-focused imagery exercises and the letter-writing exercise will be based on those used in published studies. Other exercises, such as thought monitoring and relapse prevention planning, are commonly used in cognitive behavioural therapy (CBT) and, as CFT is an adapted form of CBT, will be included in the current self-help intervention. The session content and homework exercises will build on previous sessions and homework, so there will be a clear sense of progression through the intervention. In addition, imagery and written homework exercises will be alternated, to provide variety and keep participants engaged in the intervention. Examples relating to skin conditions will be given throughout the self-help materials. Expert feedback regarding the content of the website has been sourced through personal contacts and social media. Feedback has already been gathered from three people with skin conditions. Changes to the website deemed necessary based on their feedback have been made.

Data analysis strategy Text responses from participants' feedback on the intervention overall will be analysed using content analysis to identify helpful aspects of the intervention and areas for improvement. Quantitative data (outcome measures and acceptability ratings) will be screened for outliers and missing values, and descriptive statistics will be conducted for all variables. The data will be tested for the assumption of normality. Paired t-tests will be used to test for differences in participants' psychological outcome measures before and after the intervention. This information will also be used to calculate effect sizes (dz) for changes in scores on each outcome measure. Intention-to-treat and completer analyses will be carried out.

Inclusion Criteria:

• self-report of currently having a skin condition that has been present for at least the last six months and has been diagnosed by a medical professional.
• scored 10-20 (inclusive) on DASS-DEP (depression subscale of Depression Anxiety Stress Scales).

Exclusion Criteria:

• currently receiving a psychological therapy for a mental health problem.
• current diagnosis of a serious mental illness (e.g. psychosis or bipolar disorder).
• current diagnosis of a drug or alcohol problem.

Individual patient data will not be made available to maintain confidentiality, but aggregated data may be made available from the lead researcher upon reasonable request.

Rolling recruitment: from baseline for each participant until data collection ended on Day 42. Participants also were able to contact the lead researcher by email after this point (no fixed end point for this).