A cross-sectional study was conducted in two parts, in urban and rural schools of Anand, Gujarat, India. Schools within 15 km radius of our Hospital were chosen for the study. Study was conducted over a period of one year from February 2016 to February 2017. The study was approved by the Institutional Ethics Committee vide approval letter no IEC/HMPCMCE/63/Faculty/6/41/16 dated 28/01/2016. Written informed assent was taken from the study participants and consent was taken from their teachers for each part of the study.

The first part of the study was to translate English version of CES-DC into Gujarati and validating the same.

Study population, sample size, inclusion criteria: The first part of the study population was 300 students who were sampled from one school. Inclusion criteria were: a) Gujarat medium student, b) 8^th to 12^th grade. This gave ethnic uniformity to the study sample.

SCALE 1: Centre for Epidemiological Studies Depression Scale for Children (CES-DC) [5].

The CES-DC is a valid and reliable measure of various dimensions of depressive symptoms in adolescents. It uses 20 easy to understand statements that are rated on a 4-point Likert scale from 0 to 3 (0=not at all, 1=a little, 2=some, 3=a lot). Scale generates a total score out of 60, with higher scores indicating greater number of symptoms [Annexure 1].

SCALE 2: Rosenberg’s Self-Esteem Scale

The Rosenberg’s Self-Esteem Scale (RSES) is a 10-question scale used to measure self-esteem [11]. It has previously been widely used in Indian adolescents [12,13]. It has 5 positively and 5 negatively worded questions that are rated on a 4-point Likert scale from 0 to 3 (0=strongly disagree, 1=disagree, 2=agree, 3=strongly agree). The negatively worded items are reversed scored. Sum of all items generates a total score out of 30. Higher scores indicate higher levels of self-esteem [Annexure 2].

SCALE 3: Patient Health Questionnaire-9 (PHQ-9)

The PHQ-9 Modified for Teens [ages 11-17 years] is a screening instrument with 9-items modified from PHQ-9, which is a valid and reliable measure of depression in adults. [14] It is rated for depressive symptoms experienced keeping in mind last 2 weeks. Each question is rated from 0 to 4 (0=not at all, 1=several days, 2=more than half the days, 3=nearly every day). Scale generates a total score out of 27. Cut-off scores of 5, 10 and 15 are used for mild, moderate and severe level of depression [Annexure 3].

The items were first translated from English to Gujarati by one of the authors. Back-translation was carried out by another author. The back-translated version was compared with the original. A panel of experts evaluated the translated scale (two Psychiatrists, a Physician).

The approved Gujarati version was printed and copies of the questionnaire were made. After obtaining prior permission of the authorities in charge of the concerned school and the assent of the individual students were taken, the translated Gujarati versions of the CES-DC and Rosenberg’s scale and PHQ-9 administered to 300 students from 8^th to 12^th standard. of one Gujarati medium school. Questionnaires were given in the class and students were instructed by study team person on how to fill them. Responses were scored according to the scoring system of the respective questionnaires.

Data analysis was done using SPSS version 16, SPSS Inc, Illinois, USA. The translated version was tested for semantic equivalence, content equivalence, construct validity, discriminant validity and reliability as done in the Chinese CES-DC translation study [6].

Semantic equivalence: The three experts rated each item on the translated version of the CES-DC and the translated version of RSES on a 4-point scale rating scale of semantic equivalence (1=not equivalent, 2=some equivalent, 3=equivalent, 4=most equivalent). Item that were scored as 1 or 2 by any expert were amended.

Content equivalence: The three experts rated each item on the translated version of the CES-DC and the translated version of RSES on a 4-point scale rating scale of content equivalence (1=not relevant, 2=somewhat relevant, 3=quite relevant, 4=very relevant). Item level content validity is calculated as the number of experts giving a rating of 3 or 4. As per Polit DF et al., for a three to five panel expert the acceptable item level content validity index (I-CVI) should be 1 [15].

Construct validity testing: The pearson product-moment correlation coefficient was used to judge correlation between translated CES-DC and PHQ-9 to establish construct validity. A positive correlation was hypothesised.

Discriminant validity testing: The correlation between the translated CES-DC and RSES was used to judge discriminant validity. A negative correlation was hypothesised.

Reliability testing: Cronbach’s alpha was used to judge the reliability of the translated CES-DC.

The second part of the study comprised of administering the validated Gujarati CES-DC scale to school going adolescents of Gujarati medium school for assessing the prevalence of depression among them and identifying the factors associated with the same.

Study population, sample size and inclusion criteria: Urban and rural schools of Anand district, within 15 km radius of our Hospital were chosen for the study. Five schools were included in the study. All of them were co-educational. Permission was sought from the Head of the institutions and the respective class teachers of grades 8 to 12 of the selected schools. Convenience sampling method was used. The students were explained on how to fill the questionnaire and after obtaining individual assent, the questionnaires were distributed to them. Total of 1000 students in the age group of 13-17 years participated in the study. Students who participated in the initial study to validate the questionnaire were also included in prevalence study and the school drop-outs were excluded from the study.

Study instrument consisted of validated CES-DC questionnaire and Socio-demographic profile. A cut-off score of >15 was used.

Descriptive analysis was done to assess the prevalence of depressive symptoms among the students and to identify factors contributing to the same.

Demography of the participants from the validation study are shown in [Table/Fig-1].

Semantic validity: None of the items on the translated versions of CES-DC and RSES were rated by the panel of three experts as 1 or 2.

Content validity: All items on the translated versions of CES-DC and RSES were rated by the panel of three experts as 3 or 4, thus each item on both scales had a I-CVI of 1.

Construct and discriminant validity: As was hypothesised for construct validity, there was positive correlation between translated CES-DC and PHQ-9 (r= +0.596, n=300, p<0.001). Likewise, as hypothesised there was negative correlation between translated version of CES-DC and RSES (r= -0.254, n=300, p<0.001).

The translated CES-DC had a Cronbach’s alpha value of 0.708, which suggest good reliability. Sub-scale Cronbach’s alpha coefficients were a) Somatic: 0.464 (7 items), b) Depression: 0.655 (7 items), c) Positive: 0.453 (4 items), and d) Interpersonal: 0.528 (2 items). Correlations ranging from 0.453 to 0.655 were found between individual items and total score on translated version.

A total of 1000 students studying in Class 8^th to Class 12^th were enrolled in the second part of the study, of which all the students submitted answers to all the questions. Out of all the participating students, 532 (53.2%) were found to be having depressive symptoms and 468 (46.8%) had no depressive symptoms as per the screening test CES-DC scale. The male-female ratio was comparable. Prevalence of depressive symptoms was found to be higher in boys in class 8^th, class 9^th, and class 10^th as compared to girls in the same classes. But in class 11^th and class 12^th, prevalence of depressive symptoms was higher in girls as compared to boys. Higher the class more are the depressive symptoms. There was no association between students who had depressive symptoms and type of family. In this study, the depressive symptoms are lowest among students who were born first in the family, and peaked in students who were third, fourth and fifth [Table/Fig-2].

This study examines the validity of the CES-DC as a screening tool for school going adolescents from Gujarati medium schools.

Psychometric properties of the CES-DC

The study shows that translated version of CES-DC has good internal consistency with a Cronbach’s alpha of 0.708. This finding suggests good reliability and comparable to Chinese version of CES-DC (0.80) and Kinyarwanda version of the CES-DC (0.86) [16,17]. Subscale Cronbach’s alpha coefficient for the translated scale ranged from 0.46 to 0.65 and were comparable to Cronbach’s alpha coefficients for the four subscales on the Chinese version range (0.39 to 0.57) [6].

The negative correlation between translated CES-DC and RSES (r=-0.254) indicates that those having low self-esteem had higher level of self-reported depressive symptoms. A study by Masselink M et al., has shown that low self-esteem is an enduring vulnerability for developing depressive symptoms [18]. Hence the translated scale has acceptable discriminant validity. However, this was not as strong as in the Chinese CES-DC validation study (r= -0.52) [6].

The positive correlation between CES-DC and PHQ-9 (r= +0.596) indicated that those having higher levels of self-reported depressive symptoms on PHQ-9 had higher self-reported depressive symptoms on the translated version of CES-DC. The Chinese translation had used an anxiety scale for demonstrating construct validity and had reported a correlation of r=0.63 [6]. Hence, the translated scale has acceptable convergent validity.

Adolescent period is often accompanied by new stress, behavioural change, and relationship problems and this affects psycho-social development. Adolescent mental health needs are a growing concern in both developed and developing nations. Depression in adolescents may affect their social as well as personal lives with potentially serious long-term consequences. Adolescent with depression is at high risk of mental disorders such as antisocial behaviour and substance abuse disorders [19]. The school is the most significant social context in the life of a child as almost one third of a day is spent here. Thus, it is essential to assess the prevalence of depression in school-going adolescents. Parents, teachers, school or college counsellors and other supportive adults need to be empowered to recognise and respond to emotional and behavioural difficulties among school going adolescent [20].

In the present study, a total of 1000 adolescent students studying in Class 8^th to Class 12^th were enrolled. They were studied using the validated Gujarati version of CES-DC. The study was carried out in both rural and urban Gujarati medium schools in Gujarat. The prevalence of depression among students was found to be 53.2% by using screening test. Another study showed lower prevalence (38%) of depression among adolescents [21]. In one another study by Jha KK et al., [22] prevalence of depression was found to be 49.2%. Studies in USA have found that 3-9% of adolescents meet criteria for depression at any one time, and at the end of adolescence, as many as 20% of adolescents reported a lifetime affliction of depression [23].

Boys and girls were equally distributed (57.6% and 42.4% each) in the study population, but prevalence of depression was found to be slightly higher among females than males with increasing standards (11^th and 12^th) which are consistent with the results of earlier studies [24,25]. They also mentioned high rate of depression in adolescent females attributed to hormonal differences [26]. Depression among the females was more prevalent (41.8%) as compared to that among males (35%). However, there was no statistical association between gender and depression. In one study, females had higher prevalence (62%) than the males (40.5%) [27]. Factors like self-esteem, coping ability, support from parents may explain these differences.

This study reported higher prevalence among students in class 10^th, 11^th and 12^th students (59.6%, 63.2%, and 70.3% respectively) as compared to Class 8^th and 9^th (42.7%, 48.9% respectively). Similarly, other studies have also reported a higher prevalence of depression in 10^th and 12^th division students due to the pressure of academic performance in the board examinations [28]. In the present study, it was observed that prevalence of depression among students from nuclear families was higher as compared to those from joint families. Similar observation was found in the study by Jha KK et al., [22].

The study also shows lowest prevalence of depression among students who was born first in the family, and prevalence rate peaking in students who were third, fourth and fifth order. This is consistent with a previous study [29]. Percentage distribution of depression in relation to birth order in this study was: first (51.1%), second (53.1%), third (59.2%), fourth (63.3%), and fifth (75.0%) [Table/Fig-2]. Jha KK et al., reported lowest prevalence of depression among students who were born first in the family; prevalence rate peaking in students with birth order three, and then dipping in students with birth order fourth and above [22].

The socio-economic status of the children enrolled in this study was not known. This was not done due to the practical problem of enquiring about the income of the family to minors who wouldn’t be aware of it. This was a school-based study in which those registered with the school were enrolled for the study. The adolescents who were not registered in the school might be from vulnerable section of society who are more prone for depression. The study was based on the response to CES-DC Scale (in Gujarati) by the students themselves and there may be some inaccuracy in the results.

The translated version of the CES-DC is a valid and reliable tool to assess depressive symptoms in school going adolescents among Gujarati children. The CES-DC scale is simple, short, easy-to-use questionnaire, to identify at-risk population and associated factors, which could be utilised in a general practice setting to screen adolescents for depression. Students should receive life skills education in school to learn coping skills and to mitigate other factors responsible for depression. Raising awareness amongst stake holders [parents, teachers and students] is also required. Active, early intervention can help prevent worsening of depression and its impact on life.