Cross-cultural adaptation and psychometric evaluation of the Brazilian version of the Temporal Experience of Pleasure Scale (TEPS-Br)

Abstract Introduction: Anhedonia is a critical symptom of major depressive disorder that is defined as the reduced ability to experience pleasure. The Temporal Experience of Pleasure Scale (TEPS) is commonly used to measure anhedonia and has exhibited satisfactory reliability. Objectives: We aim to perform cross-cultural adaptation of a Brazilian version of the TEPS and evaluate its psychometric properties. Method: The cross-cultural adaptation was performed according to previously established protocols. Cronbach’s alpha coefficient of internal consistency was used to establish the degree of interrelation and coherence of items. Also, we calculated the intraclass correlation coefficient to determine the stability of the scale after a proposed interval had elapsed and used exploratory factor analysis to evaluate the scale’s factor structure and content validity. Principal component analysis was used to determine the factors to be retained in the factor model. Results: The participants reported that the Brazilian version of the TEPS had good comprehensibility and applicability. The results revealed a statistically significant correlation between measures. The intraclass correlation coefficient calculated was significant. The Cronbach’s alpha value calculated indicated that the scale’s overall internal consistency was adequate. Conclusion: The Portuguese version of the TEPS scale proposed achieved good comprehensibility for the Brazilian population and its psychometric characteristics demonstrated good reliability and validity.


Introduction
Anhedonia can be briefly defined as a reduced ability to experience pleasure. 1 While being a core symptom of major depressive disorder, 2 anhedonia is also a dimensional and transdiagnostic construct identified in a wide range of diseases such as schizophrenia, obsessive-compulsive disorder, autism spectrum disorder, and substance use disorders. [3][4][5][6][7][8] Studies have shown associations between anhedonia and worse psychiatric outcomes. In a clinical trial including adolescents with treatment-resistant depression, presence of anhedonia was a predictive factor for delayed remission, regardless of other psychiatric http://dx.doi.org/10.47626/2237-6089-2020-0131 symptoms. 9 Anhedonia was also reported as one of the strongest predictors of poor psychosocial functioning in a study with 1570 outpatients treated for depression. 10 In substance use disorders, anhedonia was associated with higher alcohol craving, and higher opioid abstinence, as well as social maladjustment and poor general health. 8 Several studies have also presented an association between anhedonia and suicidal ideation. A recent metaanalysis showed that individuals with suicidal ideation had higher anhedonia scores, even in the absence of depression diagnosis. 11 A similar association was reported by Ballard et al. in a post-hoc analysis of three clinical trials designed to evaluate the effects of ketamine. 12 Anhedonia was associated with suicidal thoughts and one day after ketamine administration the improvement in anhedonia was associated with a reduction in suicidal ideation, even after adjustment for depressive symptoms. The authors suggested the reduction in anhedonia may be responsible, at least partially, for the antisuicidal effects of ketamine. 12 Additionally, studies with both pharmacological treatment and non-invasive brain stimulation have reported anhedonia as a predictor of treatment response. 13,14 The most common ways of measuring anhedonia are based on administration of self-report scales or questionnaires. The Temporal Experience of Pleasure Scale (TEPS) is a short, self-administered scale with satisfactory reliability, which was originally proposed by Gard and colleagues as a measure of hedonic capacity.
Moreover, this scale also evaluates the existence of different subcomponents of the hedonic experience, such as the anticipatory and consummatory phases. 15 Anticipatory pleasure is characterized by the individual's expectation of receiving a pleasurable reward and consummatory pleasure describes the feeling of satisfaction in response to the reward. These primarily temporal differences in the subcomponents of reward have been studied in animal models and in humans since the 1970s 4 and are associated with different underlying neurobiological mechanisms. 16 The TEPS presents 18 items, 10 of them related to the experience of anticipatory pleasure, and the other 8 related to the ability to experience pleasure at the time of action. It also has temporal stability in test-retest assessment and validity for measurement of both anticipatory and consummatory aspects of the hedonic behavior. 15 There is an increasing body of multinational and multicultural research, for which adapted measuring tools are needed. 17 The TEPS has already been adapted and validated for use in several countries, including China, 18 France, 19 Germany, 20 and Italy. 21

Methods
This cross-sectional study was conducted in two stages: a cross-cultural adaptation of the scale followed by evaluation of its psychometric properties.

Cross-cultural adaptation
The cross-cultural adaptation was performed according to previously established protocols. 17,22,23 Two independent translations into Portuguese were Gard) whose comments were also considered. The "prefinal" version of the TEPS was defined at this meeting, after discussion of all discrepancies by the evaluation committee.
In the second phase, 42 outpatients from the psychiatric clinics at the Polydoro Ernani de São Thiago University Hospital (HU/UFSC) were enrolled for the pre-final phase and administration of the scale.
These participants were interviewed to examine their understanding of each item, as well as the answers provided. This step was conducted in order to ensure that the version retained equivalence to the circumstances.
After each item, the participant was asked questions such as "Explain in your own words what you understood this question to mean," and "Were there any words in this question you did not understand?" Additionally, the participants were also asked: "Do you have any suggestions or are there any other words we could replace for ones you didn't understand?" All responses given during the process were noted. A final version was produced after the applicability analysis, taking the participants' input into consideration.

Analysis of psychometric properties
The final scale was administered to a population of 173 adult volunteers. They were all undergraduate medical students attending the second to the eleventh semester of medical school. This phase was conducted from March to April 2019 and a ratio of 10 participants per scale item was used to define the sample size. 24 Concomitantly with the application of the final version, demographic data were collected and the HADS was administered for convergent validity testing. 25   Semantics were responsible for one of the main issues observed in this phase of the study, which was also discussed with the author of the original scale.          Furthermore, item 18 influenced both components two and three, which is less problematic, since both components measure aspects related to anticipatory pleasure. A similar phenomenon occurred with items one and four which were considered crossloaded, i.e., they load onto more than one factor with weights greater than 0.3. 26 Additional testing is expected to better clarify the value of these items for the scale set. Analysis of the correlation between TEPS scores and HADS scores was non-significant. However, there was a weak correlation (r = -0.33) with the depression symptoms subscale (even items on the general scale), which shows a closer approximation between the anhedonia construct and the depression construct, when measured by the HADS. Nevertheless, it is considered that this result reveals two different constructs, and a stronger correlation would hardly be expected. Similar correlations were found in other studies that have compared these same characteristics and corroborate this observation. 19,20 Only studies using scales that specifically measured the anhedonia construct found stronger correlations. 15,27 It is suggested that this type of analysis may be performed in the future for the Brazilian population as soon as such tools have had their adaptations and validity tested for use in this population.

Cross-cultural adaptation
One limitation of this study is the lack of better concurrent and convergent validity testing. Another is the fact that the population studied in the second phase is not representative of the general population.
However, as a strength, we can highlight the cross-