Participants will complete written exercises and breathing exercises that are not associated with self-compassion

The Patient Health Questionnaire - 9 (PHQ-9) (Kroenke et al., 2001) will be used to assess the severity of depressive symptoms and assess responses to treatment. The PHQ-9 has nine items that represent each of the DSM-IV (APA) criteria of depression. The items, such as "feeling down, depressed, or hopeless?", are rated on a scale of 0 (not at all) to 3 (nearly every day) to represent how frequently the symptoms are experienced over the previous two weeks. A total score is calculated by summing the scores for each item, providing a severity score between 0 and 27. Higher scores represent more severe depression, and scores of 5, 10, 15, and 20 represent cut-off points for mild, moderate, moderately severe and severe depression, respectively.

General Anxiety Disorder- 7 (GAD-7) (Spitzer et al., 2006) will be used to assess the severity of anxiety. The GAD-7 includes 7 items that represent the DSM-IV (APA) clinical criteria. The items, such as "becoming easily annoyed or irritable", are scored on a scale between 0 (not at all) to 3 (nearly every day) to represent how frequently the symptoms are experienced over the previous two weeks. A total score between 0 - 21 is calculated by summing each individual item's rating. Higher scores represent more severe anxiety, and scores of 5, 10 and 15 are the cut-off points for mild, moderate and severe anxiety, respectively.

The Perceived Stress Scale (PSS, Cohen et al., 1983) will be used to measure participant's perception of stress. The 10-item self-report questionnaire includes four positively worded items and six negatively worded items that are rated on how frequently (never [0] - very often [4]) respondents perceive their lives as unpredictable, uncontrollable or overwhelming. Positively worded items are reverse scored, and each item response is summed to provide a total score of between 0 - 40 whereby higher scores equal higher perceived stress.

The Adult ADHD Self-report Scale (ASRS; Kessler, 2010) will be used as a screening tool to assess the frequency of ADHD symptoms and as a measuring tool to assess any changes in ADHD symptomatology over time. The measure was created in association with the World Health Organisation (WHO) and is based on the clinical criteria presented in the DSM-IV (APA, 2013). Part A is a 6-item questionnaire that assesses the frequency to which ADHD symptoms are present on a 5-point Likert Scale (Never - Always). It is recommended that individuals who report "sometimes", "often" or "very often" to the first three questions, or "often", "very often" to the final three questions four or more items, have symptoms highly consistent with ADHD.

The Self-Critical Rumination Scale (SCRS, Smart et al., 2016) is a 10-item self-report questionnaire which measures the frequency of self-criticism on a 4-point scale from not at all (0) to very well (3). Self-criticism in this measure is conceptualised as a form of negative thinking that focuses on devaluing oneself. A total score is obtained by summing item responses, whereby higher scores equal greater self-criticism. Scores can range between 0 - 30.

Acceptability of the intervention at post-intervention will be assessed following Sekhon et al.'s (2017) Theoretical Framework of Acceptability (TFA). A visual analogue rating scale will be used to measure: (1) affective attitude - how do you feel about the intervention?; (2) burden - how satisfied were you with the amount of time/effort the intervention required?; (3) ethicality - how well do you feel the intervention fits with your value system?; (4) self-efficacy - how confident are you that you could perform the intervention tasks?; (5) opportunity costs - to what extent did you have to give up something to take part in the intervention?; (6) perceived effectiveness - how confident are you that this intervention will improve your well-being?; (7) intervention coherence will be measured through a basic definitions quiz of self-compassion principles.

Mood will be measured daily using two affective sliders that rate level of alertness and level of happiness/pleasure on a 10-point scale. The two item responses are added together to give an overall score of mood between 0 and 20, whereby higher scores equal a more positive mood.

The Adult ADHD Self-report Scale (ASRS; Kessler, 2010) will be used as a measuring tool to assess any changes in ADHD symptomatology over time. The measure was created in association with the World Health Organisation (WHO) and is based on the clinical criteria presented in the DSM-IV (APA, 2013). It consists of 18 items that question the frequency of ADHD symptoms from "never" to "very often" (0 - 4) over the previous 6 months. Part A consists of 6-items that are most predictive of the disorder. Part B includes an additional 12 items which act as additional cues to participants symptoms. A total score can be obtained by summing the scores. A higher total score would represent a more frequent display of ADHD symptoms, and scores can range between 0 - 72.

Hewitt & Flett Multidimensional Perfectionism Scale (MPS-HW) Short form (2008), is a 15 item self-report questionnaire. Items are rated on a scale between 1-7 (Strongly disagree - strongly disagree), and is scored by summing responses to items. Higher scores indicate higher levels of perfectionism. Scores can range between 15 and 105.