Materials and methods

Study design and setting

This cross-sectional analytical study was conducted among undergraduate medical (MBBS) students at Believers Church Medical College Hospital, Thiruvalla, Kerala, India, between January 2019 and December 2021.

Study population and sampling

The study population consisted of all MBBS students enrolled in the institution during the study period, including students from the 2016, 2017, 2018, 2019, 2020, and 2021 admission batches (first-year to final-year MBBS students).

Sample Size

A census sampling approach was used. All undergraduate MBBS students enrolled at Believers Church Medical College Hospital during the study period (2019-2021) were considered eligible for participation. Therefore, no formal sample size calculation was performed. Instead, all 600 eligible students from the 2016-2021 admission batches were invited to participate in order to maximize study power and minimize sampling bias. A total of 507 students completed the questionnaire, yielding a response rate of 84.5%. Although the response rate was high (84.5%), characteristics of non-responders were not available for comparison; therefore, the possibility of non-response bias cannot be completely excluded.

Inclusion and exclusion criteria

The study included all MBBS students enrolled at Believers Church Medical College Hospital, Thiruvalla, Kerala, India, during the study period (2019-2021) who provided informed consent to participate. Students who did not provide informed consent or submitted incomplete questionnaire responses were excluded from the study.

Data collection procedure

Data were collected over a three-year period (January 2019 to December 2021) using a structured, self-administered questionnaire distributed electronically through Google Forms (Google LLC, California, USA). Participation was voluntary, and responses were anonymous and confidential. The questionnaire consisted of demographic information, the Social Interaction Anxiety Scale (SIAS) [11,12,13], and the Rosenberg Self-Esteem Scale (RSES) [8]. Participants were also asked to report the age at which they first experienced symptoms related to social anxiety and low self-esteem.

Study instruments

The SIAS, developed by Mattick and Clarke, is a validated 20-item self-report instrument designed to assess distress associated with social interactions and fear of negative evaluation (see Appendix A) [11]. The SIAS has demonstrated excellent internal consistency, high test-retest reliability, and good convergent and discriminant validity [11]. Each item is rated on a five-point Likert scale with response options ranging from 0 = "not at all characteristic or true of me," 1 = "slightly characteristic or true of me," 2 = "moderately characteristic or true of me," 3 = "very characteristic or true of me," and 4 = "extremely characteristic or true of me." Items 5, 9, and 11 are reverse scored. Total scores range from 0 to 80, with scores ≥35 considered indicative of clinically significant social anxiety [11,13].

The RSES is a widely used and validated 10-item measure of global self-esteem with good reliability and construct validity across diverse populations [5,8,9]. Each item is rated on a four-point Likert scale with response options 0 = "strongly disagree," 1 = "disagree," 2 = "agree," and 3 = "strongly agree." Negatively worded items (2, 5, 6, 8, and 9) are reverse scored. Total scores range from 0 to 30 in the original scoring system; in the present study, responses were coded on a 0-4 scale (maximum score 40), with scores <20 considered indicative of low self-esteem (see Appendix B).

Both the SIAS and RSES were used solely for non-commercial academic research. To the best of our knowledge, no additional permission or licensing was required for this use. Therefore, no separate permission documents were obtained.

Outcome measures

The primary outcome measures were the prevalence of social anxiety and the prevalence of low self-esteem among medical students. Secondary outcome measures included the association between social anxiety and low self-esteem, the association of gender with social anxiety and low self-esteem, and the distribution of the reported age of onset of social anxiety-related difficulties.

Statistical analysis

Data were entered and analyzed using IBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, NY, USA). Descriptive statistics were used to summarize participant characteristics and prevalence estimates. Associations between categorical variables were assessed using a chi-square (χ2) test. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Pearson and Spearman correlation analyses were performed to assess the relationship between SIAS and RSES scores. Multivariable logistic regression analysis was conducted with social anxiety as the dependent variable and relevant predictors entered into the model. Internal consistency of the SIAS and RSES was assessed using Cronbach's alpha. A p-value <0.05 was considered statistically significant. Because the primary analyses consisted of descriptive statistics, chi-square tests, odds ratios, correlation analyses, and logistic regression, formal assessment of homogeneity of variances was not applicable. Pearson and Spearman correlation coefficients were used to account for the distributional characteristics of the data.

Ethical considerations

Informed consent was obtained from all participants prior to inclusion. Participant anonymity and confidentiality were maintained throughout the study. The study was approved by the Institutional Ethics Committee at Believers Church Medical College, Thiruvalla, Kerala, India (Reg No.: ECR/1118/lNST/KL/2019). Before accessing the questionnaire, participants were presented with an electronic Participant Information Sheet describing the study objectives, voluntary nature of participation, expected time required, confidentiality measures, and contact details of the principal investigator. Participants were required to provide electronic informed consent by selecting an "I agree to participate" option before proceeding to the questionnaire. Those who declined consent could not access the survey. Responses were collected anonymously, and no personally identifying information was obtained. Consequently, individual participants with elevated SIAS or low RSES scores could not be identified or contacted. Participants were informed that the questionnaires were screening tools rather than diagnostic instruments and were advised to seek professional mental health evaluation if they experienced significant psychological distress.