[VOLUME 5 I ISSUE 4 I OCT. – DEC. 2018] e ISSN 2348 –1269, Print ISSN 2349-5138 http://ijrar.com/ Cosmos Impact Factor 4.236 Research Paper IJRAR- International Journal of Research and Analytical Reviews 359 A Study Of The Relationship Between Psychological Well-Being And Body Mass Index Of Adolescents Using Ex-Post Facto Research Design. Aditya Pareek 1 & Dr. Uma Joshi 2 1 Research Scholar, Ph.D. (Clinical Psychology), Amity Institute of Behavioral and Allied Sciences (AIBAS), Amity University Rajasthan, Jaipur. 2 Ph.D., Former: Dean, Humanities, Social Science and Liberal Arts; Former: Director, Amity Institute of Behavioral and Allied Sciences (AIBAS), Amity University Rajasthan, Jaipur. Received: July 01, 2018 Accepted: August 21, 2018 ABSTRACT Physical and mental health go hand in hand.The mental health, specifically psychological well-being associated with underweight and obesity is as much a serious concern as physical problems. The sample consisted of 250 adolescents and their Body mass index was measured with the help of BMI machine and criteria for measuring BMI was taken from Indian Academy of Pediatrics. The result were computed with the help of SPSS software using ANOVA and Duncan multiple range test. To assess Psychological well-being of adolescents scale by Birleson, (1990) was used. It was found that adolescents who were obese and underweight scored significantly higher scores on psychological well- being scale indicating poor psychological well-being in comparison to normal weight adolescents. It shows that poor psychological well-being can be a cause or effect of obesity or underweight at an early age. Keywords: Adolescents, BMI, Obesity, Psychological Well-Being,Underweight. Introduction Physical and mental health go hand in hand (Reilly & Kelly, 2010). The mental health, specifically psychological well-being associated with underweight and obesity is as much a serious concern as physical problems (Reilly & Kelly, 2010). At times children with higher and lower than normal BMI has to undergo various types of weight-related teasing such as- name calling, peer teasing (Neumark-Sztainer et al., 2002). It complicated with weight-related gender dynamics(Madowitz, Knatz, Maginot, Crow & Boutelle, 2012). Obese and underweight children may face weight-related bullying since childhood and it may continue till adulthood and may cause a decrease in self-esteem or depressive symptoms(Bell et al., 2007). Adolescent obesity is consistently associated with both poor psychological and social functioning (Roberts & Hao, 2013). Obesity in adolescence has been found to be associated with a range of poor psychological outcomes. Previous research has indicated that adolescent girls are particularly susceptible to appearance-related anxiety with those who are obese reporting more negative physical perceptions of themselves and lower self-worth than their average weight peers (BeLue, Francis & Colaco, 2009). For young women in western societies, being overweight is often equated with being “ugly”, rendering them more susceptible to bullying and victimization (Chrisler, 2011). Zametkin, Zoon, Klein & Munson, (2004) reported that obese adolescents show more sadness, loneliness, and anxiety than their healthy weight peers, in addition to more emotional and behavioral problems. Furthermore, Fonseca, Matos, Guerra & Gomes-Pedro, (2010) replicated these issues with overweight adolescents. Forste & Moore, (2012) found lower life-satisfaction among overweight adolescent girls relative to healthy weight girls, and this negative association operates through perceptions of self, peers, parents, and school which may impact their subjective well-being. Adolescent obesity is reported to be strongly associated with poor psychological functioning and is a strong predictor of depression in adolescent females (Boutelle, Hannan, Fulkerson, Crow & Stice, 2010), and is significantly associated with low self-esteem (McClure, Tanski, Kingsbury, Gerrard & Sargent, 2010). Health-related quality of life is also significantly poorer in obese children and adolescents than in healthy-weight counterparts (Daniels, Armstrong, Malone & Burgess, 2010). Social stigma related to peer-pressure and conformity has a strong association with obesity in adolescence. Obese or overweight adolescents are more likely to experience peer victimization and stigma than their healthy weight counterparts. Adolescent obesity also carries significant physical health implications with a higher risk of a wide range of illnesses, including Type II diabetes, various cancers and cardiovascular illness (Benjamin, 2010). Similarly to obesity, underweight children also suffer from the poor psychological state of mind (Fairburn, Cooper & Shafran, 2003). Few types of research report adverse effect of underweight on thinking, concentration, lack of interest in things and nearby environment (Fairburn, Cooper & Shafran, 2003; Vanlint, 2013; Fairburn et al., 2015). Fairburn et al., (2015) reported