Review of Theory
Self-determination theory (SDT) posits that three interconnected psychological needs—autonomy, relatedness, and competence—predict motivation and wellbeing (Deci, Olafsen, & Ryan, 2017). That is, holistic health will more likely be achieved when someone feels (a) free to make decisions that are important to his/her health or well-being (autonomy); (b) valued, accepted, supported, and included by personal and professional significant others (connectedness or relatedness); and (c) a sense of mastery or self-efficacy about skills and behaviors needed for achieving relevant goals (competence Gourlan, Trouilloud, & Sarrazin, 2013; Ryan, Patrick, Deci, & Williams, 2008). Like the social ecological model, SDT emphasizes the critical nature of socio-contextual factors in human development (Deci et al., 2017).
A growing body of research suggests the three SDT constituents are positively associated with improved health-related behavior. In particular, autonomy contributes to improved self-regulation across cognitive, emotional, motivational, and behavioral dimensions over a lifespan (Miller et al., 2018). Also, social support or connectedness is understandably important for behavior change in general, and health behavior is no exception. In fact, there is a push to integrate social relationships and support into federal, state, and local public health priorities given the robust, compelling body of research supporting the role of.social support in health (Holt-Lunstad, Robles, & Sbarra, 2017). The third element of SDT, competence, has an important, established role in both general and health behavior change (Bachmann et al., 2016; Ryan et al., 2008; Strecher, McEvoy DeVellis, Becker, & Rosenstock, 1986). Competence alone, however, is insufficient in achieving sustainable health behavior change. The SDT model emphasizes the importance of autonomy and competence together in ensuring adherence to health behavior change (Ryan et al., 2008).
There is a significant body of knowledge supporting SDT-based health behavior change in adults. Autonomous motivation and behavioral regulation help promote and maintain physical exercise, weight loss, and adherence (Silva et al., 2010). Similarly, increased autonomy is predictive of higher physical activity among primary care patients (Fortier, Sweet, O’Sullivan, & Williams, 2007) as well as post-bariatric patients (Gonzalez-Cutre, Megías, Beltràn-Carrillo, Cervelló, & Spray, 2018).
Evidence in Youth
Multimodal interventions integrating SDT have improved obesity treatment outcomes in children and adolescents. For instance, Delamater et al. (2013) developed a web-based family platform for intervention with children who were overweight (8 to 12 years). The intervention was based in SDT concepts, and the authors created an instrument (the Intrinsic Motivation Inventory for Weight Management) that measured participant self-efficacy and perceived importance of weight management. They found that compliance with the web-based intervention improved both Body Mass Index (BMI) and dietary intake. Another randomized controlled trial of 54 adolescents examined outcomes of an SDT-based intervention. Specifically, the intervention group received standard weight loss program (SWLP) on physical activity (PA) practice plus motivational interviewing (MI; n = 26) while the control group received only SWLP (и = 28). The SWLP + MI group lost more weight, increased physical activity over time, and showed improved motivation relative to the SWLP-only group (Gourlan et al., 2013).
Although limited, there is emerging evidence that SDT-based interventions promote physical activity in youth. For example, activity increases have been strongly associated with elevated autonomous motivation, and autonomous motivation has been associated with a more positive disposition towards physical activity (Vier-ling, Standage, & Treasure, 2007). Notably, autonomy-facilitating contexts that included teachers and parents predicted autonomous motivation pertaining to physical activity. Consistent with these findings, increased autonomous motivation among adolescents with obesity was associated with increased physical activity (Verloigne et al., 2011).
As noted previously, screen time—including time spent on watching television, working/playing on a computer, and game consoles—is an obesogenic agent that adversely influences healthy physical activity (Trandafir et al., 2018). SDT-based interventions have been successfully applied to reduce screen time. One SDT-based intervention that included (a) classes on fitness and health, (b) a healthy physical activity program, and (c) meetings with families produced reductions in screen time in adolescents (Gonzâlez-Cutre et al., 2018). The program heavily emphasized a combination of self-efficacy, tailored programming (autonomy), and connectedness. Another Australian school-based program utilizing an SDT-informed smart phone intervention (for 12-14 year-old boys from low-income households) found the intervention effective in reducing screen time and controlling consumption of certain unhealthy foods, while also increasing muscular fitness (Smith et al., 2014).
The Smith study noted above found an SDT-based smart phone intervention helpful in reducing the consumption of sugar-sweetened beverages by 12—14 year-old boys from low-income backgrounds (Smith et al., 2014). There is more support for healthy eating from SDT-based interventions for adults. This could be a function of the relatively limited control children and adolescents have over their own food environments. One multi-component program called the Kid’s Choice Program, ultimately rooted in SDT, demonstrated an increase in consumption of fresh fruits and vegetables as well as healthy beverages by children who participated (Hendy, Williams, & Camise, 2011). Interestingly, this intervention was delivered by parent volunteers and was very cost effective (Hendy et al., 2011). Another parent-directed intervention that focused on individualized changes in home food environments, psychoeducation and skill-based instruction about energy balance, self-management of weight, and social support significantly improved home food environments, parent weight loss, and child weight loss despite no direct contact with the children (Anderson, Newby, Kehm, Barland, & Hearst, 2014).
SDT has long been applied to tobacco cessation but has limited research on its application to alcohol and drug abuse (Smith, 2011). Research on self-determination interventions and tobacco finds that these interventions are successful in reducing smoking behavior. For example, a study by Williams, Cox, Kouides, and Deci (1999) examined two different types of messages regarding smoking, one being supportive of autonomy and one without autonomous messages, with a sample of9th-12th grade adolescents (n = 400). The results of this study found that adolescents who received messages regarding not smoking being supportive of autonomy had more autonomous motivation for smoking cessation that predicted decreases in smoking. Another study conducted by Slater, Kelly, Lawrence, Stanley, and Comello (2011) looked to use media campaigns focused on emphasizing the inconsistency of marijuana use with personal autonomy. The study was conducted with adolescents with a mean age of 12.4 years (n = 3,236). Results of the study found that exposure to the autonomous messages regarding marijuana use predicted reduced marijuana use. Although there is more work to be done, interventions focused on self-determination appear to be promising in reducing adolescent substance use.
Risky Sexual Behavior
The research on self-determination on risky sexual behavior is limited. Research that has been done has mainly examined the relationships between self-determination (autonomy) and risky sexual behavior rather than interventions. Hardy, Dollahite, Johnson, and Christensen (2015) found that adolescents with higher motivation profiles, and profiles higher in autonomous motivation (rather than controlled motivation), demonstrated lower levels of risky sexual behavior. Given the limited research in this area, additional work is needed to determine the usefulness of a self-determination framework on reducing adolescent risky sexual behavior.