Date of Award




Document Type

Master's Thesis

Degree Name

Master of Arts (MA)


Department of Psychology


Clinical Psychology

Content Description

1 online resource (iii, 36 pages)

Dissertation/Thesis Chair

Drew A. Anderson

Committee Members

Julia M. Hormes


Diagnosis, Disordered eating, Eating pathology, Orthorexia nervosa, Undergraduates, College students, Eating disorders, Exercise addiction, Perfectionism (Personality trait), Health attitudes, Food habits, Diet

Subject Categories

Clinical Psychology | Psychiatric and Mental Health | Social and Behavioral Sciences


The pursuit of a healthy lifestyle has become a central focus of Western societies over the past few decades. As rates of chronic conditions, such as obesity and type II diabetes, continue to rise, so too has the desire to maintain one’s optimal state of health. For some, the pursuit of a healthy diet becomes an obsession that interferes with one’s physical and psychological wellbeing. Orthorexia Nervosa (ON) is a proposed eating disorder characterized by a pathological fixation on healthy eating. Unlike other established eating disorders (EDs), ON is focused on the quality of one’s diet, rather than the quantity of food consumed. Although researchers have attempted to define and measure ON, no standardized diagnostic tools exist, and current measurement tools lack sufficient psychometric properties. There is also debate as to whether ON constitutes its own unique diagnosis, or if ON is merely a variation of another EDs, such as anorexia nervosa. As such, the current study aimed to examine the relationship between ON and ED symptomatology using a newly created measure of ON, the Orthorexia Nervosa Inventory (ONI). This study also examined the relationship of ONI to other ED-related constructs, such as compulsive exercise, maladaptive perfectionism, and intolerance of uncertainty. Participants were undergraduate students from a large, Northeastern university who completed a series of online, self-reported questionnaires. Study measures included the ONI, the Eating Attitudes Test (EAT-26), the Compulsive Exercise Test (CET), the Frost Multidimensional Perfectionism Scale – Concern Over Mistakes subscale (FMPS-COM), and the Intolerance of Uncertainty short scale (IUS-12). Relationships between all variables were assessed using Pearson correlations, and multiple linear regression was conducted to determine how much unique variance in EAT-26 scores was explained by the ONI. All variables were positively related to ON, and the ONI demonstrated unique predictive ability towards the EAT-26 (b=.061, p<.001), even after controlling for other ED-related constructs (F(6,245)=32.43, p<.001, R2=.429). This study lends support to the categorization of ON as a unique ED and highlights the clinical need to remain vigilant to patient symptoms that resemble ON symptomatology. Furthermore, more research using the ONI as a measurement tool is important to determine the reliability and validity of the measure.