Promoting Positive Emotions in Adolescents Using Positive Events Training: An Indicated Approach

Mean value of four daily diary items (i.e., "How relaxed, content, enthusiast, good do you feel?"), rated on a 0 ("not at all") to 100 ("a lot") rating scale. Higher values represent, higher levels of positive emotions (min = 0, max = 100).

Mean value of four daily diary items (i.e., "How relaxed, content, enthusiast, good do you feel?"), rated on a 0 ("not at all") to 100 ("a lot") rating scale. Higher values represent, higher levels of positive emotions (min = 0, max = 100).

Mean value of three daily diary items tapping into difficulties experiencing consummatory pleasure, anticipatory pleasure and motivational difficulties using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you find it difficult to enjoy yourself?"; "To what extent did you look forward to doing enjoyable things? (reverse-scored), "Conditional: if 0-50 ("not at all - neutral"): Was this because there really weren't any enjoyable things to look forward to, or because they were there but you couldn't really look forward to them?; "How happy did you feel?" (reverse-scored)). Higher score reflects higher levels of anhedonia (min = 0, max = 100).

Mean value of three daily diary items tapping into difficulties experiencing consummatory pleasure, anticipatory pleasure and motivational difficulties using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you find it difficult to enjoy yourself?"; "To what extent did you look forward to doing enjoyable things? (reverse-scored), "Conditional: if 0-50 ("not at all - neutral"): Was this because there really weren't any enjoyable things to look forward to, or because they were there but you couldn't really look forward to them?; "How happy did you feel?" (reverse-scored)). Higher score reflects higher levels of anhedonia (min = 0, max = 100).

Mean value of four daily life items to measure mental strategies to reduce the intensity and/or frequency of positive emotions, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you think, "This pleasant feeling won't last"?"; "To what extent did you think, "I don't deserve to feel good"?"; To what extent did you think, "Something might go wrong that will make my good/pleasant feeling go away"?; "To what extent did you think about how difficult it would be if your good/pleasant feeling suddenly disappeared?"). Higher score reflects higher levels of dampening (min = 0, max = 100).

Mean value of four daily life items to measure mental strategies to reduce the intensity and/or frequency of positive emotions, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you think, "This pleasant feeling won't last"?"; "To what extent did you think, "I don't deserve to feel good"?"; To what extent did you think, "Something might go wrong that will make my good/pleasant feeling go away"?; "To what extent did you think about how difficult it would be if your good/pleasant feeling suddenly disappeared?"). Higher score reflects higher levels of dampening (min = 0, max = 100).

Mean value of two daily life items tapping into the the engagement in attending to, appreciating and enhancing positive experiences, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you allow the good/pleasant feeling to be there and simply let it be?", "To what extent did you try to really focus your attention on the good/pleasant feeling in order to fully experience it and truly enjoy it?"). Higher scores reflect a higher tendency to savor (min = 0, max = 100).

Mean value of two daily diary items tapping into the the engagement in attending to, appreciating and enhancing positive experiences, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "To what extent did you allow the good/pleasant feeling to be there and simply let it be?", "To what extent did you try to really focus your attention on the good/pleasant feeling in order to fully experience it and truly enjoy it?"). Higher scores reflect a higher tendency to savor (min = 0, max = 100).

Mean value of three daily diary items to measure anxiety, stress and depressed feelings, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "How anxious did you feel?"; "How depressed (down) did you feel?"; "How stressed did you feel?"). A higher score reflects higher levels of emotional distress (min = 0, max = 100).

Mean value of three daily diary items to measure anxiety, stress and depressed feelings, using a 0-100 Likert scale (0 = "not at all", 100 = "a lot"; items: "How anxious did you feel?"; "How depressed (down) did you feel?"; "How stressed did you feel?"). A higher score reflects higher levels of emotional distress (min = 0, max = 100).

8 cue words in response to which a positive future event is generated, accompanied with single-item rating scales ranging from 1 (not at all) to 9 (very much). In line with the study of Hallford, Yeow, et al. (2020), participants rate the index of detail (IoD), mental imagery (MI), anticipated (AdP) and anticipatory pleasure (AyP), and perceived control (PC) and perceived likelihood of occurrence (PLO) associated with the generated future events on the EFT-T. Higher scores reflect higher levels of the feature of interest (min = 8; max = 72).

8 cue words in response to which a positive future event is generated, accompanied with single-item rating scales ranging from 1 (not at all) to 9 (very much). In line with the study of Hallford, Yeow, et al. (2020), participants rate the index of detail (IoD), mental imagery (MI), anticipated (AdP) and anticipatory pleasure (AyP), and perceived control (PC) and perceived likelihood of occurrence (PLO) associated with the generated future events on the EFT-T. Higher scores reflect higher levels of the feature of interest (min = 8; max = 72).

8 cue words in response to which a positive past event is recalled, accompanied with single-item rating scales ranging from 1 (not at all) to 9 (very much). Participants rate the index of detail (IoD), mental imagery (MI), felt and remembered pleasure (FP and RP), associated with the recalled past events on the AMT. Higher scores reflect higher levels of the feature of interest (min = 8; max = 72).

8 cue words in response to which a positive past event is recalled, accompanied with single-item rating scales ranging from 1 (not at all) to 9 (very much). Participants rate the index of detail (IoD), mental imagery (MI), felt and remembered pleasure (FP and RP), associated with the recalled past events on the AMT. Higher scores reflect higher levels of the feature of interest (min = 8; max = 72).

Positive affect will be assessed via the Positive Affect subscale of the Positive and Negative Affect Schedule Scales (PANAS; Engelen et al., 2006; Watson et al., 1988). The extent to which 10 positive feelings (e.g., "enthusiastic") were experienced is rated on a 5-point scale ranging from 1 (rarely) to 5 (very often), with higher scores reflecting higher positive affect (min = 10, max = 50).

Positive affect will be assessed via the Positive Affect subscale of the Positive and Negative Affect Schedule Scales (PANAS; Engelen et al., 2006; Watson et al., 1988). The extent to which 10 positive feelings (e.g., "enthusiastic") were experienced is rated on a 5-point scale ranging from 1 (rarely) to 5 (very often), with higher scores reflecting higher positive affect (min = 10, max = 50).

12 items rated on a 1-5 Likert scale (1 = "This is completely incorrect for me.", 5 = "This is completely correct to me"). A higher total score reflects higher levels of anhedonia (min = 12, max = 60).

12 items rated on a 1-5 Likert scale (1 = "This is completely incorrect for me.", 5 = "This is completely correct to me"). A higher total score reflects higher levels of anhedonia (min = 12, max = 60).

The Leuven Exeter Dampening Scale (LEDS, Bogaert et al., 2025) consists of 13 items rated on a 5-point scale ranging from 1 (not at all) to 5 (very often). A higher score reflects a higher dampening tendency (min = 13, max = 65).

The Leuven Exeter Dampening Scale (LEDS, Bogaert et al., 2025) consists of 13 items rated on a 5-point scale ranging from 1 (not at all) to 5 (very often). A higher score reflects a higher dampening tendency (min = 13, max = 65).

The 10 savoring items of the abridged Ways of Savoring Checklist for Adolescents (not yet validated in Dutch) taps into diverse savoring strategies (WOSC; Chadwick, 2012). Items (e.g., "I looked for other people to share it with") are rated on a 7-point scale ranging from 1 (totally disagree) to 7 (totally agree). Higher scores reflect higher levels of engagement in the respective emotion regulation strategy (min = 10, max = 70).

The 10 savoring items of the abridged Ways of Savoring Checklist for Adolescents (not yet validated in Dutch) taps into diverse savoring strategies (WOSC; Chadwick, 2012). Items (e.g., "I looked for other people to share it with") are rated on a 7-point scale ranging from 1 (totally disagree) to 7 (totally agree). Higher scores reflect higher levels of engagement in the respective emotion regulation strategy (min = 10, max = 70).

21 items, rated on a 0-3 Likert scale (0 = "Not at all applicable", 3 = "Almost always applicable"). Higher total (subscale) scores reflect higher levels of emotional distress (depressive symptoms, anxious symptoms and stress; min = 0, max = 63).

21 items, rated on a 0-3 Likert scale (0 = "Not at all applicable", 3 = "Almost always applicable"). Higher total (subscale) scores reflect higher levels of emotional distress (depressive symptoms, anxious symptoms and stress; min = 0, max = 63).

Statements of the Connor-Davidson Resilience Scale (10 items; e.g., "I am able to adapt to change") are rated on a 5-point scale ranging from 1 (not at all) to 5 (very often), with higher scores reflecting higher levels of resilience (min = 10, max = 50).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent did you feel that you were able to handle many things at the same time?", adapted from Martinez-Corts et al., 2015).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent were you able to cope easily with those feelings of stress?", adapted from Brogly et al., 2024).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent did you try to think of something pleasant from the past or the future to cope with that stress?", new item).

Statements of the Connor-Davidson Resilience Scale (10 items; e.g., "I am able to adapt to change") are rated on a 5-point scale ranging from 1 (not at all) to 5 (very often), with higher scores reflecting higher levels of resilience (min = 10, max = 50).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent did you feel that you were able to handle many things at the same time?", adapted from Martinez-Corts et al., 2015).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent were you able to cope easily with those feelings of stress?", adapted from Brogly et al., 2024).

Daily diary item rated on a 0-100 Likert (0 = not at all; 100 = a lot), with higher scores reflecting higher daily-life resilience (item: "To what extent did you try to think of something pleasant from the past or the future to cope with that stress?", new item).

This self-report scale comprises 7 statements (e.g., "I have been feeling relaxed") rated on a 5-point scale ranging from 1 (never) to 5 (always). Higher scores indicate higher self-reported wellbeing (min = 7, max =35).

This self-report scale comprises 7 statements (e.g., "I have been feeling relaxed") rated on a 5-point scale ranging from 1 (never) to 5 (always). Higher scores indicate higher self-reported wellbeing (min = 7, max =35).

This is a 5-item scale measuring the core characteristics of repetitive negative thinking (Magson et al., 2019). The items are answered on a 5-point frequency scale ranging from never (1) to almost always (5). A higher score reflect higher levels of persisitent negative thinking (min = 5, max = 25).

This is a 5-item scale measuring the core characteristics of repetitive negative thinking (Magson et al., 2019). The items are answered on a 5-point frequency scale ranging from never (1) to almost always (5). A higher score reflect higher levels of persisitent negative thinking (min = 5, max = 25).

Self-report scale consisting of 5 items (e.g., "When I go through difficult things, I realize that others also experience tough moments sometimes, just like I do."), rated on a Likertscale from 1 (never or almost never) to 5 (almost always). A higher score reflects higher levels of common humanity (min = 5, max = 25).

Self-report scale consisting of 5 items (e.g., "When I go through difficult things, I realize that others also experience tough moments sometimes, just like I do."), rated on a Likertscale from 1 (never or almost never) to 5 (almost always). A higher score reflects higher levels of common humanity (min = 5, max = 25).