Intervention for the Promotion of Gratitude

The PANAS consists of 20 items with a range from 1 (very slightly or not at all) to 5 (extremely). Respondents have to indicate the extent to which they experienced the feeling or emotion during the past few weeks. This scale evaluates two independent dimensions: positive affect and negative affect. The maximum score for each subscale is 50. The scale showed excellent internal consistency (α between .84 and .90) and convergent and discriminant validity. The Spanish version has demonstrated high internal consistency (α = 0.89 and 0.91 for positive affect and negative affect in women, respectively, and α = 0.87 and 0.89 for PA and NA in men, respectively) in college students.

The GQ-5 consists of six items that measure span, frequency, intensity and density of gratitude and primarily focuses on the unidimensional emotional component of gratitude. Participants have to rate six items (e.g., "I have so much in life to be thankful for") on a seven-point Likert scale (GQ-6: α = 0.82)

This is a life satisfaction scale consisting of five items. Participants are asked to indicate their degree of agreement with each statement using a 7-point Likert scale (from 1 = strongly disagree to 7 = strongly agree). Scores can range from 5 to 35 points, indicating a greater life satisfaction with higher scores (alpha = .88).

The OASIS is a 5-item self-report scale that evaluates the frequency and severity of anxiety symptoms, the functional impairment related to these symptoms (i.e. school, work, home, or social impairment), and behavioral avoidance. Each item instructs respondents to endorse one of five responses that best describes their experiences over the past week. Response items are coded from 0 to 4, added together to obtain a total score ranging from 0 to 20. Previous studies have shown good internal consistency (α = 0.80), test-retest reliability, and convergent and discriminant validity. The Spanish version has shown good internal consistency (α = 0.86), and convergent and discriminant validity.

The ODSIS is a brief self-reported scale with 5 items that assess the severity and functional impairment associated with depressive symptoms. Items are coded on a 5-point scale (0-4). The sum of the scores is used to obtain the total score, which can be a maximum of 20. The measure has shown excellent internal consistency (α = 0.94 in an outpatient sample, 0.92 in a community sample, and 0.91 in a student sample) and good convergent/discriminant validity. The Spanish validation has excellent internal consistency (α = 0.93), as well as convergent and discriminant validity.

The Pemberton Happiness Index (PHI) is a self-reported scale of overall well-being that includes both remembered and experienced well-being. PHI index incorporates two components: (a) an 11-item measure that includes general, eudaimonic, hedonic, and social well-being rated on a scale from 0 to 10 (in this scale, participants are asked to rate each statement using a scale from 0 -fully disagree- to 10 -fully agree-) and (b) a single score that results from the combination of positive and negative experiences from the day before, also on a scale from 0 to 10. The scale has shown excellent internal consistency in Spanish samples (alpha between .91 and .92).

The Dispositional Hope Scale (DHS) is a 12-item instrument, with 4 pathways items, measuring abilities to identify feasible ways to goal, and four agency items, which evaluate motivations for pursuing goals, and four filler items. Items are scored in a scale from 1(definitely false) to 4 (definitely true). In the Spanish version, Cronbach's alphas ranged between .67 and .83.

The SHS is a 4-item Likert-type (from 1 to 7) scale measure that evaluates global subjective happiness using statements with which participants either self-rate themselves or compare themselves to others. The scale has an adequate unitary structure and temporal stability confirmed in 14 samples, showing moderate correlations with constructs such as self-esteem, depression, satisfaction, or neuroticism.

The scale comprises 6 items, rated on a scale from 0 (nothing at all) to 9 (completely), that cover how logical the treatment seems to be, how successfully the patients think the treatment will be in reducing their symptoms, how confident they are in recommending the treatment to a friend, how much improvement in their symptoms they think will occur, how much they really feel that therapy will help them to reduce their symptoms, and how much improvement in their symptoms they really feel will occur.