Health-Care, Self-Determination Theory Packet

1. Abstract

The Health-Care, Self-Determination Theory Packet is an integrated suite of psychometric instruments designed to operationalize and evaluate the motivational, cognitive, and interpersonal dimensions of health behavior change within the conceptual architecture of Self-Determination Theory (SDT; Deci & Ryan, 1985, 2000). Developed under the leadership of Geoffrey C. Williams, Edward L. Deci, and Richard M. Ryan, the packet consolidates three distinct yet theoretically interlocked measurement tools: the Treatment Self-Regulation Questionnaire (TSRQ), the Perceived Competence Scale (PCS), and the Health Care Climate Questionnaire (HCCQ). Across behavioral domains—including smoking cessation, dietary modification, physical exercise adherence, alcohol moderation, diabetes glycemic control, and medical treatment adherence—the battery captures how supportive healthcare environments facilitate autonomous motivation and feelings of competence, ultimately driving sustained lifestyle change.

The centerpiece of the packet, the TSRQ, evaluates the underlying regulatory styles that govern health actions along the self-determination continuum. In its full operationalization, the instrument comprises 15 items stratified into three primary subscales: Autonomous Motivation (6 items capturing identified and integrated regulation), Controlled Motivation (6 items assessing external and introjected regulation), and Amotivation (3 items capturing non-intentionality or absence of regulation). Items are evaluated on a 7-point Likert-type scale ranging from 1 (“not at all true”) to 7 (“very true”). Confirmatory factor analyses across diverse clinical cohorts consistently confirm a multidimensional factor structure, demonstrating strong factor loadings (> .60) and solid goodness-of-fit indices (CFI > .92, RMSEA < .06). Subscale internal consistencies consistently yield Cronbach’s alpha coefficients exceeding .80 for autonomous and controlled regulation across multiple clinical populations. Companion instruments within the battery exhibit parallel psychometric robustness: the 4-item PCS achieves internal consistency coefficients around α = .90, while the 6-item short form and 15-item full version of the HCCQ routinely record alphas between .82 and .96. This article provides an extensive psychometric synthesis of the Health-Care SDT Packet, detailing its theoretical foundation, structural validity, score calculation methodologies, clinical utility, and complete item inventories.

2. Keywords

Self-Determination Theory, Treatment Self-Regulation Questionnaire, TSRQ, Health Care Climate Questionnaire, HCCQ, Perceived Competence Scale, autonomous motivation, controlled motivation, health behavior change, smoking cessation, medication adherence, psychometrics

3. Authors

The Health-Care, Self-Determination Theory Packet was formulated and psychometrically validated through long-standing collaborations among prominent clinical researchers and experimental social psychologists centered at the University of Rochester:

• Geoffrey C. Williams, M.D., Ph.D.: Professor Emeritus of Medicine, Psychiatry, and Psychology, Department of Medicine and Clinical and Social Sciences in Psychology, University of Rochester, Rochester, New York, USA. Dr. Williams has led pioneering clinical trials applying Self-Determination Theory to primary care interventions, smoking cessation, diabetes self-management, and cardiovascular risk reduction.
• Edward L. Deci, Ph.D.: Professor of Psychology and Gowen Professor of the Social Sciences Emeritus, Department of Clinical and Social Sciences in Psychology, University of Rochester, Rochester, New York, USA; Professorial Fellow, Australian Catholic University, Sydney, Australia. Co-founder of Self-Determination Theory.
• Richard M. Ryan, Ph.D.: Professor at the Institute for Positive Psychology and Education, Australian Catholic University, North Sydney, Australia; Professor Emeritus of Psychology, University of Rochester, Rochester, New York, USA. Co-founder of Self-Determination Theory and pioneer in organismic integration research.
• Collaborating Psychometricians and Clinical Investigators: Notable contributors to specific questionnaire iterations and validation studies include Chantal S. Levesque (Missouri State University), Diane Elliot (Oregon Health & Science University), Martin A. Pickering, Bradley Bodenhamer, Patrick J. Finley, Wendy S. Grolnick, and Robert W. Plant.

4. Purpose

Chronic lifestyle-related medical conditions—such as atherosclerotic cardiovascular disease, type 2 diabetes mellitus, chronic obstructive pulmonary disease, and obesity—require persistent, long-term modifications in daily human behavior. Traditional behavior change frameworks in medicine have predominantly relied on extrinsic compliance mechanisms, coercive health warnings, external surveillance, or physician-directed authority. Although such methods may generate short-term behavioral conformity, empirical evidence indicates they routinely fail to yield enduring lifestyle transformation, characterized instead by high relapse rates, treatment attrition, and psychological reactance.

The primary purpose of the Health-Care, Self-Determination Theory Packet is to provide clinicians, behavioral scientists, and clinical trialists with psychometrically validated instruments that diagnose why patients initiate, maintain, or abandon health-related behaviors. Drawing from SDT’s process model of healthcare, the packet conceptualizes health behavior transformation not merely as the acquisition of behavioral habits, but as an internalization process wherein individuals integrate health-relevant values into their core identity.

Clinically, the packet fulfills several distinct functions:

• Diagnostic Assessment of Motivational Quality: By measuring autonomous versus controlled regulatory styles via the TSRQ, the packet allows clinicians to ascertain whether a patient’s motivation is driven by authentic personal commitment (autonomous) or by interpersonal pressure, guilt, or fear of disapproval (controlled).
• Evaluation of Clinical Interpersonal Climates: Through the HCCQ, the battery allows health systems and training programs to measure whether healthcare providers support patient autonomy, acknowledge patient perspectives, and provide meaningful rationales, or whether they employ controlling, paternalistic styles.
• Measurement of Behavioral Self-Efficacy and Agency: Through the PCS, the battery monitors patients’ domain-specific feelings of efficacy and confidence regarding their capacity to institute and sustain demanding lifestyle modifications (e.g., maintaining long-term smoking abstinence or adhering to complex insulin regimens).
• Structural Testing of Mediation Pathways: In intervention research, the packet enables structural equation modeling of the theoretical chain of change: an autonomy-supportive healthcare climate (HCCQ) predicts enhancements in autonomous self-regulation (TSRQ) and perceived competence (PCS), which jointly predict sustained behavioral adherence and objective biological markers (e.g., glycosylated hemoglobin, serum cotinine levels, lipid profiles).

5. Psychological Construct

The Health-Care, Self-Determination Theory Packet assesses three core psychological constructs operationalized across specialized subscales:

1. Behavioral Self-Regulation (TSRQ)

Within Self-Determination Theory, motivation is not analyzed solely as a unitary quantitative property (i.e., how much motivation an individual possesses), but as a qualitative continuum of behavioral regulation. The TSRQ evaluates where an individual’s reasons for health action reside along this perceived locus of causality (PLOC) continuum:

• Autonomous Regulatory Style: Represents behaviors driven by an internal perceived locus of causality. Autonomous regulation encompasses two distinct forms of internalized motivation: identified regulation (wherein the behavior is consciously valued as personally meaningful and aligned with health goals) and integrated regulation (wherein the health behavior is fully assimilated into the individual’s core values and identity). In the TSRQ, autonomous items capture convictions such as taking personal responsibility for health, aligning actions with central life goals, and valuing health as vital to overall well-being (e.g., Item 1: “Because I feel that I want to take responsibility for my own health”; Item 11: “Because it is consistent with my life goals”).
• Controlled Regulatory Style: Represents behaviors driven by an external perceived locus of causality, where action is pressured, coerced, or seductively guided by external contingencies. Controlled regulation comprises external regulation (acting to satisfy external demands, obtain social rewards, avoid punishment, or appease significant others) and introjected regulation (acting to avoid internal sanctions such as guilt, shame, and self-derogation, or to achieve contingent self-worth and social approval). In the TSRQ, controlled items capture both interpersonal pressures (e.g., Item 4: “Because others would be upset with me if I smoked”; Item 9: “Because I feel pressure from others to not smoke”) and intrapsychic pressures (e.g., Item 2: “Because I would feel guilty or ashamed of myself if I smoked”; Item 7: “Because I would feel bad about myself if I smoked”).
• Amotivation: Reflects a complete absence of intentionality, self-determination, or perceived contingency between actions and outcomes. Individuals who are amotivated experience helplessness, lack of purpose, or an inability to comprehend why they should undertake the targeted health behavior (e.g., Item 5: “I really don’t think about it”; Item 15: “I don’t really know why”).

2. Perceived Competence (PCS)

Perceived competence designates the degree to which an individual feels capable, effective, and confident in overcoming barriers to initiate and maintain a specific health-related behavior over the long term. While structurally cognate to Albert Bandura’s concept of perceived self-efficacy, perceived competence within SDT is explicitly positioned as one of three basic psychological needs necessary for psychological thriving. The PCS does not measure generalized global confidence; rather, it assesses targeted perceived efficacy toward specific behavioral demands (e.g., permanently abstaining from tobacco, adhering consistently to exercise routines, or maintaining nutritional self-restraint).

3. Perceived Autonomy Support (HCCQ)

The healthcare climate construct assesses patients’ subjective appraisals of their therapeutic encounters. An autonomy-supportive healthcare climate is characterized by practitioners who:

• Elicit and acknowledge the patient’s personal perspective and emotional experiences;
• Provide relevant choices, options, and shared decision-making regarding regimens;
• Offer meaningful medical rationales when specific actions are recommended;
• Refrain from pressuring, controlling language, guilt-induction, or coercive strategies;
• Convey empathy and unconditional positive regard, supporting the patient’s competence.

6. Theoretical Framework

The Health-Care Packet is grounded in Self-Determination Theory (Deci & Ryan, 1985; Ryan & Deci, 2017), an organismic-dialectical meta-theory of human development and motivation. SDT posits that all human beings possess inherent growth tendencies and innate psychological needs that operate as psychological nutriments required for optimal functioning, constructive social development, and personal well-being.

Organismic Integration Theory (OIT)

A primary sub-theory underpinning the TSRQ is Organismic Integration Theory. OIT details the continuum of internalization through which non-intrinsically motivated behaviors (such as taking antihypertensive medication, enduring dietary restrictions, or tolerating nicotine withdrawal) can become autonomous. Because health behaviors are rarely intrinsically enjoyable at the outset, behavior change depends on internalizing extrinsic behavioral regulations:

1. External Regulation: Lowest autonomy; behavior is sustained solely by tangible rewards, surveillance, or fear of punitive consequences.
2. Introjected Regulation: The contingency is internalized, but the behavior is energized by guilt, contingent self-esteem, or fear of social judgment; the individual feels an internal compulsion.
3. Identified Regulation: The individual consciously endorses the value of the health behavior, accepting it as personally important.
4. Integrated Regulation: The highest form of extrinsic internalization, wherein the behavior harmonizes with the person’s integrated identity, core values, and life philosophy.

The TSRQ collapses these stages into composite autonomous (identified + integrated) and controlled (external + introjected) dimensions, reflecting the empirical clustering observed in factor analyses of health behaviors (Ryan & Connell, 1989; Williams et al., 1996).

Basic Psychological Needs Theory (BPNT)

A complementary sub-theory, Basic Psychological Needs Theory, postulates three universal psychological needs:

• Autonomy: The experience of volition, agency, and self-endorsement of one’s actions.
• Competence: The experience of mastery, effectiveness, and capability to navigate challenges.
• Relatedness: The experience of warmth, care, mutual understanding, and connection to others.

In the healthcare context, Williams, Deci, and Ryan (1998) formulated the Self-Determination Model of Health Behavior. This model demonstrates that when the healthcare environment satisfies these basic needs—predominantly through an autonomy-supportive climate (measured by the HCCQ)—patients experience an expansion in their perceived competence (measured by the PCS) and autonomous self-regulation (measured by the TSRQ). This motivational cascade enhances psychological vitality, self-management adherence, and objective clinical markers.

7. Validity

The Health-Care SDT Packet has undergone extensive psychometric validation across medical settings, observational cohorts, and randomized clinical trials:

Construct and Structural Validity

Levesque et al. (2007) conducted a definitive structural validation study of the TSRQ across three independent health behaviors: healthy eating, regular physical activity, and tobacco abstinence. Multi-sample confirmatory factor analyses verified that the hypothesized three-factor structure (Autonomous Regulation, Controlled Regulation, and Amotivation) provided an excellent fit across all three samples, confirming metric invariance. Factor loadings across items were uniformly strong, loading distinctly onto their respective constructs without cross-loadings above .25.

Convergent and Discriminant Validity

Studies have verified clear discriminant validity between autonomous self-regulation (TSRQ) and perceived competence (PCS). While positively correlated (typically r = .30 to .50), structural equation modeling demonstrates they operate as distinct latent constructs with independent predictive paths toward health outcomes (Williams, Freedman, & Deci, 1998). Convergent validity has been established by demonstrating positive associations between autonomous regulation and measures of dispositional autonomy, internal health locus of control, and general self-efficacy, alongside inverse correlations with depressive symptoms, external health locus of control, and amotivation.

Predictive and Criterion Validity

The predictive validity of the packet’s scales is supported by longitudinal health outcome data:

• Glycemic Control in Diabetes: In a prospective study of patients with type 2 diabetes mellitus, Williams, Freedman, and Deci (1998) found that baseline HCCQ scores predicted increases in autonomous motivation (TSRQ) and perceived competence (PCS) over 12 months, which in turn directly predicted significant reductions in glycosylated hemoglobin (ΔHbA1c > -0.5%, p < .01).
• Tobacco Abstinence: Williams et al. (1999, 2006) established in large-scale clinical trials (e.g., N = 1,006 adult smokers) that patients who perceived their physicians as autonomy-supportive on the HCCQ demonstrated significantly higher autonomous motivation (TSRQ) and perceived competence (PCS), leading to higher 6-month and 24-month validated 7-day point-prevalence and prolonged tobacco abstinence confirmed via serum cotinine.
• Weight Loss and Dietary Maintenance: In a landmark investigation of adult outpatients participating in an intensive 6-month weight loss program, Williams, Grow, Freedman, Ryan, and Deci (1996) demonstrated that baseline autonomous motivation measured by the TSRQ prospectively predicted both 6-month weight reduction and sustained weight loss maintenance at a 23-month follow-up, whereas controlled motivation was associated with greater attrition and weight regain.
• Medication Adherence: Williams, Rodin, Ryan, Grolnick, and Deci (1998) evaluated outpatients prescribed chronic medication regimens, documenting that autonomous regulation on the TSRQ significantly predicted objectively validated pill-count adherence over 14 weeks (β = .32, p < .001).

8. Reliability

The instruments within the Health-Care SDT Packet demonstrate high internal consistency and longitudinal temporal stability across diverse clinical settings:

Treatment Self-Regulation Questionnaire (TSRQ)

Across validation studies spanning smoking cessation, diet modification, and exercise initiation (e.g., Levesque et al., 2007; Williams et al., 1996, 1999), internal consistency metrics consistently achieve robust benchmarks:

• Autonomous Motivation Subscale: Cronbach’s alpha coefficients routinely range from α = .80 to α = .88.
• Controlled Motivation Subscale: Cronbach’s alpha coefficients range from α = .75 to α = .84.
• Amotivation Subscale: Despite comprising only 3 items, the subscale exhibits satisfactory reliability, with alpha coefficients varying between α = .71 and α = .79.
• 8-Item Short Form: In studies utilizing the abbreviated 8-item version (4 autonomous items, 4 controlled items), alphas remain stable: autonomous α ≈ .80–.85; controlled α ≈ .73–.79.

Perceived Competence Scale (PCS)

The 4-item PCS demonstrates exceptionally high internal consistency across all behavioral applications. Across trials involving diabetes self-management, smoking cessation, and physical exercise (Williams, Freedman, & Deci, 1998; Williams et al., 2006), Cronbach’s alpha for the PCS has consistently hovered at α ≈ .90, demonstrating strong item homogeneity without redundancy.

Health Care Climate Questionnaire (HCCQ)

The HCCQ exhibits excellent internal consistency across both of its primary structural formats:

• 15-Item Original Version: Cronbach’s alpha coefficients consistently exceed .90 (typically α = .92 to .96) across outpatients, primary care attendees, and specialized disease management centers (Williams, Grow, et al., 1996).
• 6-Item Short Form: Optimized for structural equation modeling and large survey batteries to minimize participant burden, the 6-item version yields robust reliability coefficients consistently around α = .82 to .86.

9. Factor Analysis

The factorial validity of the instruments in the Health-Care Packet has been systematically established via both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA).

Structural Modeling of the TSRQ

Initial factor analytic investigations by Williams et al. (1996) using principal components analysis with varimax and oblimin rotations confirmed two distinct primary factors corresponding to autonomous and controlled self-regulation. In their comprehensive psychometric investigation across 4,288 individuals participating in healthcare behavior interventions, Levesque et al. (2007) subjected the 15-item TSRQ to multi-group structural equation modeling across three health domains (diet, exercise, smoking):

• Model Specifications: A three-factor model specifying Autonomous Regulation (Items 1, 3, 6, 8, 11, 13), Controlled Regulation (Items 2, 4, 7, 9, 12, 14), and Amotivation (Items 5, 10, 15) as correlated latent factors was evaluated.
• Fit Indices: The three-factor solution yielded acceptable to strong fit statistics across all behavioral groups: Comparative Fit Index (CFI) ranged from .92 to .95; Non-Normed Fit Index (NNFI / TLI) > .91; Root Mean Square Error of Approximation (RMSEA) ranged from .052 to .064 (90% CI: .048–.068); Standardized Root Mean Square Residual (SRMR) ≤ .058.
• Factor Loadings: Standardized factor loadings for autonomous items ranged from .62 to .84. Standardized factor loadings for controlled items ranged from .55 to .78. Amotivation items yielded loadings ranging from .58 to .81. Cross-factor loadings remained negligible.
• Invariance Testing: Factorial invariance tests supported full metric invariance across distinct clinical behavior groups, confirming that the underlying conceptual dimensions are measured equivalently regardless of the specific behavioral domain.

Structural Modeling of the PCS and HCCQ

Confirmatory factor analyses of the 4-item PCS consistently confirm a strictly unidimensional latent factor, with standardized factor loadings typically exceeding .80 (e.g., .82, .88, .89, and .85), explaining over 75% of the total item variance. Similarly, CFA investigations of the 6-item and 15-item HCCQ establish a single, robust latent dimension of “Perceived Autonomy Support,” with short-form loadings routinely exceeding .70, demonstrating that healthcare climate is empirically perceived by patients as a cohesive interpersonal style.

10. Instrument / Measurement Tool

The operational specifications of the instruments comprising the Health-Care SDT Packet are structured as follows:

• Tool Name: Health-Care, Self-Determination Theory Packet (encompassing the TSRQ, PCS, and HCCQ).
• Constructs Assessed: Autonomous Motivation, Controlled Motivation, Amotivation, Perceived Competence, and Perceived Autonomy Support.
• Administration Format: Paper-and-pencil self-report or computer-administered survey instrument. Can be administered individually or as an embedded clinical intake module.
• Target Populations: Adults and adolescents participating in medical care, outpatient counseling, disease management programs, or clinical lifestyle intervention trials.
• Administration Time:
  • Complete 15-item TSRQ: 4–6 minutes.
  • 4-item PCS: 1–2 minutes.
  • 6-item short HCCQ: 2–3 minutes.
  • Total battery time: Approximately 8–12 minutes.
• Response Scale: 7-point Likert scale:
  • 1 = not at all true
  • 2 = [unlabeled anchor]
  • 3 = [unlabeled anchor]
  • 4 = somewhat true
  • 5 = [unlabeled anchor]
  • 6 = [unlabeled anchor]
  • 7 = very true
• Scoring and Computational Procedures:
  • TSRQ Autonomous Motivation Subscale: Calculate the mean of items # 1, 3, 6, 8, 11, and 13. High scores reflect greater internalized, autonomous behavioral regulation.
  • TSRQ Controlled Motivation Subscale: Calculate the mean of items # 2, 4, 7, 9, 12, and 14. High scores reflect greater external or introjected regulation.
  • TSRQ Amotivation Subscale: Calculate the mean of items # 5, 10, and 15. High scores reflect perceived lack of control or intentionality.
  • Relative Autonomous Motivation Index (RAMI): In clinical trials and regression models where a single composite index of relative autonomy is required, the index is computed as:
    RAMI = Mean(Autonomous Items) - Mean(Controlled Items)
    Positive values indicate predominantly autonomous regulation, whereas negative values indicate predominantly controlled regulation.
  • Perceived Competence Scale (PCS): Calculate the arithmetic mean of items # 1, 2, 3, and 4. Higher scores reflect greater perceived self-efficacy and behavioral mastery.
  • Health Care Climate Questionnaire (HCCQ – 6 Item): Calculate the arithmetic mean of all 6 items. Higher scores reflect an interpersonal environment perceived as highly autonomy-supportive.

11. Permissions & Fee and Test Year

The instruments within the Health-Care, Self-Determination Theory Packet were developed across successive empirical investigations spanning from 1995 (Ryan, Plant, & O’Malley, 1995; Williams et al., 1996) through formal structural validations in 2007 (Levesque et al., 2007). All instruments developed by the Self-Determination Theory research group are classified as open-access for academic, scientific, and non-commercial clinical research purposes. In accordance with the principles maintained by the developers, the questionnaires can be utilized and adapted without royalty fees or formal written copyright permission, provided that appropriate scholarly attribution is maintained in all subsequent publications and presentations.

Researchers intending to modify the instruments for novel disease contexts or commercial applications should consult the formal guidelines maintained at the official Self-Determination Theory research portal (selfdeterminationtheory.org). The copyright remains held by the original authors (Geoffrey C. Williams, Edward L. Deci, and Richard M. Ryan).

12. References

• Deci, E. L., & Ryan, R. M. (1985). Intrinsic motivation and self-determination in human behavior. Plenum Publishing Co. https://doi.org/10.1007/978-1-4899-2271-7
• Deci, E. L., & Ryan, R. M. (2000). The “what” and “why” of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11(4), 227–268. https://doi.org/10.1207/S15327965PLI1104_01
• Levesque, C. S., Williams, G. C., Elliot, D., Pickering, M. A., Bodenhamer, B., & Finley, P. J. (2007). Validating the theoretical structure of the Treatment Self-Regulation Questionnaire (TSRQ) across three different health behaviors. Health Education Research, 22(5), 691–702. https://doi.org/10.1093/her/cyl148
• Pelletier, L. G., Tuson, K. M., & Haddad, N. K. (1997). Client Motivation for Therapy Scale: A measure of intrinsic motivation, extrinsic motivation, and amotivation for therapy. Journal of Personality Assessment, 68(2), 414–435. https://doi.org/10.1207/s15327752jpa6802_11
• Ryan, R. M., & Connell, J. P. (1989). Perceived locus of causality and internalization: Examining reasons for acting in two domains. Journal of Personality and Social Psychology, 57(5), 749–761. https://doi.org/10.1037/0022-3514.57.5.749
• Ryan, R. M., & Deci, E. L. (2017). Self-determination theory: Basic psychological needs in motivation, development, and wellness. Guilford Press. https://doi.org/10.1521/978.14625/28806
• Ryan, R. M., Plant, R. W., & O’Malley, S. (1995). Initial motivations for alcohol treatment: Relations with patient characteristics, treatment involvement, and dropout. Addictive Behaviors, 20(3), 279–297. https://doi.org/10.1016/0306-4603(94)00072-7
• Williams, G. C., Cox, E. M., Kouides, R., & Deci, E. L. (1999). Presenting the facts about smoking to adolescents: The effects of an autonomy supportive style. Archives of Pediatrics & Adolescent Medicine, 153(9), 959–964. https://doi.org/10.1001/archpedi.153.9.959
• Williams, G. C., Deci, E. L., & Ryan, R. M. (1998). Building health-care partnerships by supporting autonomy: Promoting maintained behavior change and positive health outcomes. In A. L. Suchman, P. Hinton-Walker, & R. Botelho (Eds.), Partnerships in healthcare: Transforming relational process (pp. 67–87). University of Rochester Press.
• Williams, G. C., Freedman, Z. R., & Deci, E. L. (1998). Supporting autonomy to motivate glucose control in patients with diabetes. Diabetes Care, 21(10), 1644–1651. https://doi.org/10.2337/diacare.21.10.1644
• Williams, G. C., Gagné, M., Ryan, R. M., & Deci, E. L. (2002). Facilitating autonomous motivation for smoking cessation: An experimental test of basic self-determination theory. Health Psychology, 21(1), 40–50. https://doi.org/10.1037/0278-6133.21.1.40
• Williams, G. C., Grow, V. M., Freedman, Z. R., Ryan, R. M., & Deci, E. L. (1996). Motivational predictors of weight loss and weight-loss maintenance. Journal of Personality and Social Psychology, 70(1), 115–126. https://doi.org/10.1037/0022-3514.70.1.115
• Williams, G. C., McGregor, H. A., Sharp, D., Levesque, C., Kouides, R. W., Ryan, R. M., & Deci, E. L. (2006). Testing a self-determination theory intervention for motivating tobacco cessation: Supporting autonomy and competence in a clinical trial. Health Psychology, 25(1), 91–101. https://doi.org/10.1037/0278-6133.25.1.91
• Williams, G. C., Rodin, G. C., Ryan, R. M., Grolnick, W. S., & Deci, E. L. (1998). Autonomous regulation and long-term medication adherence in adult outpatients. Health Psychology, 17(3), 269–276. https://doi.org/10.1037/0278-6133.17.3.269
• Zeldman, A., Ryan, R. M., & Fiscella, K. (2004). Client motivation, autonomy support and contemporary outcome in a methadone maintenance program. Journal of Applied Social Psychology, 34(6), 1144–1162. https://doi.org/10.1111/j.1559-1816.2004.tb02000.x

13. Items of the Scale (Questionnaire)