Health-Care, Self-Determination Theory Packet

1. Abstract

The Health-Care, Self-Determination Theory Packet represents a unified psychometric battery formulated by Geoffrey C. Williams, Richard M. Ryan, and Edward L. Deci to assess the core motivational and relational dynamics underpinning health behavior change. Grounded in Self-Determination Theory (SDT), the battery operationalizes how autonomy, perceived competence, and interpersonal support drive sustained health-related actions. Central to this packet is the Treatment Self-Regulation Questionnaire (TSRQ), a 15-item psychometric instrument designed to evaluate individual motivational orientations across three distinct regulatory styles along the organismic integration continuum: autonomous motivation (comprising identified and integrated regulation), controlled motivation (comprising external and introjected regulation), and amotivation. Complementing the TSRQ, the packet incorporates the 4-item Perceived Competence Scale (PCS) to evaluate domain-specific self-efficacy and agency, alongside the 6-item short form (and 15-item full version) of the Health Care Climate Questionnaire (HCCQ) to quantify patient perceptions of practitioner autonomy support.

Administered using a standardized 7-point Likert scale ranging from 1 (not at all true) to 7 (very true), the packet has been tailored and validated across multiple preventative and therapeutic domains, including smoking cessation, nutritional improvement, regular exercise, and responsible alcohol consumption. Extensive structural equation modeling (SEM) and confirmatory factor analyses demonstrate that the TSRQ exhibits robust construct validity, structural stability across diverse clinical cohorts, and pronounced discriminant validity when contrasted with perceived competence. Internal consistency reliabilities across literature consistently achieve Cronbach’s alpha coefficients between α = .73 and α = .93 across the autonomous and controlled subscales, while the PCS regularly exceeds α = .90, and the HCCQ achieves values above α = .82 (short form) and α = .90 (long form). Empirically, autonomous self-regulation and perceived competence prospectively predict long-term smoking cessation, verified glycemic control (HbA1c), sustained weight loss, and chronic medication adherence.

2. Keywords

Self-Determination Theory, Treatment Self-Regulation Questionnaire, TSRQ, Perceived Competence Scale, Health Care Climate Questionnaire, Autonomous Motivation, Controlled Motivation, Smoking Cessation, Health Behavior Change, Organismic Integration Theory, Psychometrics

3. Authors

The instruments comprising the Health-Care, Self-Determination Theory Packet were conceptualized, operationalized, and psychometrically validated by primary investigators at the University of Rochester:

• Geoffrey C. Williams, MD, PhD: Professor of Medicine, Psychiatry, and Clinical and Social Psychology at the University of Rochester Medical Center (URMC), Rochester, NY, USA. Dr. Williams has led translational clinical trials applying Self-Determination Theory to chronic illness prevention, physician-patient communication, tobacco dependence, and metabolic disease management.
• Richard M. Ryan, PhD: Co-founder of Self-Determination Theory; Professor at the Institute for Positive Psychology and Education, Australian Catholic University, North Sydney, Australia, and Professor Emeritus of Clinical and Social Sciences in Psychology at the University of Rochester. Dr. Ryan has published extensively on human motivation, personality development, and psychological well-being.
• Edward L. Deci, PhD (1942–2023): Co-founder of Self-Determination Theory; former Helen F. and Fred H. Gowen Professor of Psychology at the University of Rochester. Dr. Deci’s seminal theoretical and empirical investigations laid the groundwork for contemporary understandings of intrinsic motivation, extrinsic incentives, and basic psychological needs.

4. Purpose

The central purpose of the Health-Care, Self-Determination Theory Packet is to quantify the psychological processes that determine why individuals initiate, maintain, or abandon health behavior modifications. Historically, clinical behavior change interventions relied heavily on cognitive-behavioral constructs, social learning paradigms, or blunt external contingencies such as fear appeals, incentives, and clinician directives. While these traditional models could predict short-term compliance during acute programmatic monitoring, they frequently failed to explain post-intervention relapse. The Health-Care SDT Packet was formulated to overcome this limitation by systematically evaluating qualitative distinctions in human motivation, specifically differentiating self-determined volitional behavior from behavior driven by introjected pressures or external mandates.

At the core of the packet, the Treatment Self-Regulation Questionnaire (TSRQ) fulfills several clinical and research objectives:

• Assessing Quality of Motivation: Rather than viewing motivation as a unitary, quantitative dimension (i.e., how much motivation an individual possesses), the TSRQ measures qualitative styles of behavioral regulation. It distinguishes between patients pursuing change out of deep personal value (autonomous regulation) versus those acting to avoid guilt or satisfy external pressures (controlled regulation).
• Predicting Maintained Behavior Change: Research across behavioral medicine indicates that the autonomous regulatory subscale serves as a potent prospective predictor of long-term adherence. It differentiates patients who sustain difficult regimens—such as lifelong smoking cessation or chronic disease management—from those who return to high-risk behaviors once clinical oversight ceases.
• Evaluating Health Care Climates: The integration of the TSRQ with the Health Care Climate Questionnaire (HCCQ) enables investigators to test mediation pathways. Clinicians can determine whether an autonomy-supportive clinical style directly fosters internal self-regulation and psychological competence, thereby yielding objective biological gains such as reduced viral load or improved glycemic control.
• Intervention Tailoring: Clinically, the TSRQ can be administered at baseline to screen individuals at high risk of treatment attrition due to dominant external regulation or amotivation, permitting clinicians to adopt specialized autonomy-supportive counseling techniques (e.g., Motivational Interviewing aligned with SDT principles).

The packet has been adapted to address multiple health behaviors, including smoking cessation, dietary management, physical activity engagement, and responsible alcohol consumption. By employing uniform response structures across these disparate behavioral domains, the packet offers researchers a standardized methodology to compare motivational profiles across distinct clinical populations.

5. Psychological Construct

The instruments within the Health-Care, Self-Determination Theory Packet operationalize several interrelated psychological constructs derived from contemporary motivational science. The constructs encompass internal regulatory orientations, subjective competence appraisals, and perceived interpersonal atmospheres.

Autonomous Regulatory Style

Autonomous motivation represents the most self-determined and volitional form of behavioral regulation. Within the TSRQ, autonomous regulation is primarily operationalized through identified regulation and integrated regulation. In identified regulation, the individual has consciously evaluated the target health behavior, recognized its inherent utility, and personally accepted its value (e.g., “Because I personally believe it is the best thing for my health”). Integrated regulation occurs when this identification is brought into full congruence with the individual’s core values, beliefs, and overarching identity (e.g., “Because it is consistent with my life goals”). Autonomously regulated individuals experience a strong internal perceived locus of causality (I-PLOC); their behavioral engagement is characterized by vitality, reduced psychological conflict, psychological ownership, and enhanced perseverance in the face of setbacks.

Controlled Regulatory Style

Controlled motivation characterizes behaviors enacted under perceived internal or external pressure, reflecting an external perceived locus of causality (E-PLOC). The TSRQ measures two operational tiers of controlled motivation:

• External Regulation: The least autonomous form of extrinsic motivation, wherein behavioral enactment is contingent upon tangible rewards, compliance with explicit practitioner or familial mandates, or the evasion of interpersonal conflict and punishment (e.g., “Because others would be upset with me if I smoked” or “Because I feel pressure from others to not smoke”).
• Introjected Regulation: A partially internalized form of regulation in which the behavior is driven by internal psychological sanctions, such as ego involvement, anticipated shame, self-recrimination, or guilt (e.g., “Because I would feel guilty or ashamed of myself if I smoked”). Although introjected regulation is internally generated, the individual experiences it as controlling, compulsory, and psychologically alienating, frequently leading to psychological distress and treatment drop-out.

Amotivation

Amotivation reflects the absence of intentionality, behavioral agency, or psychological value toward the target behavior. Amotivated individuals either do not act at all or act purely passively without personal intent (e.g., “I really don’t think about it” or “I don’t really know why”). In health-care settings, amotivation emerges from feelings of severe incompetence, an inability to perceive a contingency between behavior change and health outcomes, or an utter lack of personal relevance regarding the recommended therapeutic regimen.

Perceived Competence

Measured via the 4-item Perceived Competence Scale (PCS), this construct denotes an individual’s felt sense of confidence, capability, and mastery in executing and maintaining a specific health-related behavior over the long term (e.g., “I am able to meet the challenge of not smoking”). While conceptually aligned with Albert Bandura’s construct of self-efficacy, perceived competence in SDT focuses on the psychological satisfaction derived from effective functioning within autonomy-supportive contexts.

Perceived Autonomy Support (Health Care Climate)

Assessed via the Health Care Climate Questionnaire (HCCQ), this construct reflects the patient’s perception of the interpersonal climate cultivated by medical providers. An autonomy-supportive climate is defined by practitioners who actively elicit and acknowledge patient perspectives, provide meaningful physiological rationales for recommendations, offer genuine therapeutic choices (including the choice not to change), and minimize coercive language, control, or interpersonal judgment.

6. Theoretical Framework

The conceptual foundation of the Health-Care Packet is Self-Determination Theory (Deci & Ryan, 1985; Ryan & Deci, 2017), a macro-theory of human personality, motivation, and psychological wellness. SDT posits that humans are active, growth-oriented organisms with an innate propensity toward psychological integration and optimal functioning. However, this actualizing tendency requires continuous psychological nourishment from the social environment. Specifically, SDT conceptualizes motivation through several interlocking mini-theories that directly underpin the TSRQ, PCS, and HCCQ.

Organismic Integration Theory (OIT)

The TSRQ is directly derived from Organismic Integration Theory, which describes the multidimensional continuum of extrinsic motivation. OIT rejects the simplistic dichotomy between intrinsic and extrinsic motivation, proposing that extrinsically motivated behaviors can vary substantially in their degree of autonomy depending on how successfully they have been internalized. Internalization refers to the active psychological process through which individuals assimilate socially prescribed practices or health directives into personal values.

The continuum moves sequentially from non-regulation (amotivation) to external regulation, introjected regulation, identified regulation, and integrated regulation. By capturing these specific positions, the TSRQ operationalizes where a patient resides on this continuum. Rather than treating extrinsic motivation as inherently maladaptive, SDT posits that identified and integrated forms of extrinsic motivation function effectively as autonomous self-regulation, providing the primary motivational fuel for health behaviors that are rarely intrinsically enjoyable (e.g., taking daily medications, enduring nicotine withdrawal, or restricting caloric intake).

Basic Psychological Needs Theory (BPNT)

SDT identifies three fundamental, universal psychological needs essential for psychological health and sustained behavior change:

• Autonomy: The experience of volition, self-governance, and psychological freedom in one’s actions.
• Competence: The experience of mastery, effectiveness, and capacity to produce desired behavioral outcomes (assessed by the PCS).
• Relatedness: Feeling valued, understood, and safely connected to significant others, including medical providers.

When the healthcare environment satisfies these basic needs, patients are empowered to internalize behavioral regulations. Conversely, when clinical environments thwart autonomy through authoritarian demands, patients default to controlled regulation or amotivation, precipitating behavioral failure.

Cognitive Evaluation Theory (CET) and Climate Models

Cognitive Evaluation Theory explains how contextual events (e.g., interpersonal communication, feedback, and structural constraints) influence internal motivation. In the health-care context, this is operationalized through the HCCQ. Autonomy-supportive health-care climates provide informational, non-judgmental feedback, recognize the patient’s emotional resistance, and convey unconditional positive regard. This supportive climate nurtures both perceived competence and autonomous self-regulation, establishing a structural mediation chain: Health Care Climate → Autonomous Regulation & Perceived Competence → Objective Health Outcomes.

7. Validity

The psychometric validity of the instruments comprising the Health-Care SDT Packet has been substantiated through extensive empirical research spanning diverse clinical settings, patient cohorts, and experimental designs.

Construct and Factorial Validity

Construct validity for the TSRQ was rigorously established across multiple health domains in seminal validation studies, notably by Levesque et al. (2007). Conducting confirmatory factor analyses across large cross-sectional and longitudinal cohorts engaging in diet improvement, regular exercise, and tobacco cessation, the investigators demonstrated that the multi-dimensional structure of autonomous motivation, controlled motivation, and amotivation fits empirical data consistently across distinct behavioral regimens. The latent factors exhibit appropriate convergent validity, with individual items loading robustly (> .60) onto their designated regulatory constructs.

Convergent Validity

Convergent validity is documented through significant associations with theoretically aligned psychological constructs. Autonomous regulation on the TSRQ correlates positively with validated indices of self-actualization, internal locus of control, readiness to change stages (Transtheoretical Model contemplation and maintenance stages), treatment attendance, and broad psychological well-being. Controlled regulation correlates with psychological distress, public self-consciousness, perceived stress, and external pressure scales. The Perceived Competence Scale (PCS) correlates strongly with general self-efficacy measures, while demonstrating clear conceptual independence from the TSRQ subscales.

Discriminant Validity

A critical milestone in the validation of the packet was demonstrating that perceived autonomy (TSRQ) and perceived competence (PCS) represent distinct constructs. In a landmark study of diabetic patients, Williams, Freedman, and Deci (1998) utilized structural equation modeling to confirm that while perceived autonomy and perceived competence were moderately correlated, they occupied unique structural positions. Path analyses revealed that an autonomy-supportive health care climate directly predicted perceived competence and autonomous regulation, but perceived competence specifically mediated the direct relationship between autonomous motivation and objective metabolic control.

Predictive and Ecological Validity

The instruments within the packet demonstrate predictive validity across objective physiological and behavioral endpoints:

• Smoking Cessation: In randomized controlled trials (Williams, Cox, Kouides, & Deci, 1999; Williams et al., 2006), autonomous regulation on the TSRQ and high scores on the PCS significantly predicted biochemically verified, 6- and 24-month continuous tobacco abstinence. Patients who experienced provider autonomy support demonstrated higher autonomous motivation, which directly mediated quitting success.
• Glycemic Control: Williams, Freedman, and Deci (1998) found that diabetic patients with elevated autonomous motivation and perceived competence exhibited statistically significant, clinically meaningful reductions in glycated hemoglobin (HbA1c) over a 12-month follow-up period.
• Weight Management: In longitudinal evaluations of weight-loss programs (Williams, Grow, Freedman, Ryan, & Deci, 1996), initial autonomous regulation predicted higher rates of program completion, regular physical activity, and sustained weight loss maintenance at two-year follow-up examinations. Controlled regulation, conversely, was associated with rapid weight regain post-intervention.
• Medication Adherence: Outpatient evaluations by Williams, Rodin, Ryan, Grolnick, and Deci (1998) established that autonomous regulation prospectively predicted long-term medication adherence tracked via electronic pill-monitoring systems.

8. Reliability

The instruments within the Health-Care SDT Packet display high internal consistency and structural stability across diverse clinical environments.

Internal Consistency

Extensive psychometric investigations consistently demonstrate strong internal consistency coefficients across all subscales:

• Treatment Self-Regulation Questionnaire (TSRQ):
  • Autonomous Motivation Subscale (6 items): Cronbach’s alpha coefficients range between α = .81 and α = .93 across tobacco cessation, diet, and physical activity studies (Levesque et al., 2007; Williams et al., 1996).
  • Controlled Motivation Subscale (6 items): Cronbach’s alpha coefficients consistently fall between α = .73 and α = .87, reflecting acceptable to good internal reliability across clinical populations.
  • Amotivation Subscale (3 items): Alpha coefficients generally range from α = .71 to α = .82, showing adequate consistency despite its brief 3-item length.
• Perceived Competence Scale (PCS): The 4-item PCS consistently exhibits internal consistency, with Cronbach’s alpha values routinely documented at or above α = .90 across all validated behavioral domains (Williams, Freedman, & Deci, 1998; Williams et al., 1996).
• Health Care Climate Questionnaire (HCCQ): The original 15-item HCCQ yields alpha values exceeding α = .90 (often α = .92 to α = .96). The 6-item short form, widely utilized in structural equation modeling, demonstrates reliable consistency with Cronbach’s alpha regularly documented between α = .82 and α = .88.

Test-Retest Stability

Temporal stability assessments over short-term test-retest intervals (2 to 4 weeks) in non-intervention cohorts demonstrate stability coefficients ranging from r = .76 to r = .86 for the autonomous and controlled subscales of the TSRQ. In clinical intervention trials, however, scores are systematically responsive to autonomy-supportive educational counseling, exhibiting expected shifts toward elevated autonomous regulation over time.

9. Factor Analysis

The structural composition of the TSRQ has been evaluated across exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) paradigms to substantiate its multi-dimensional scoring hierarchy.

Confirmatory Factor Analysis (CFA) Evidence

In the primary multi-sample psychometric validation study conducted by Levesque et al. (2007), CFA was employed to examine the factor structure of the 15-item TSRQ across three health behaviors (smoking cessation, healthy diet, and regular exercise). Multiple competing structural models were tested:

1. A single-factor unidimensional model (representing a general motivation construct).
2. A two-factor model differentiating autonomous from non-autonomous reasons.
3. A three-factor model positing separate latent factors for Autonomous Motivation, Controlled Motivation, and Amotivation.

Across all clinical samples, the hypothesized three-factor model demonstrated good fit to the data, outperforming alternative specifications. Standard fit indices conformed to rigorous structural criteria:

• Comparative Fit Index (CFI): Ranged from .92 to .96 across health domains.
• Tucker-Lewis Index (TLI): Consistently reached or exceeded .91.
• Root Mean Square Error of Approximation (RMSEA): Estimated between .046 and .062 (with 90% confidence intervals well within the acceptable threshold < .08).
• Standardized Root Mean Square Residual (SRMR): Fell below .058 across evaluated cohorts.

Factor Loadings and Structural Invariance

Standardized factor loadings across items consistently range from .60 to .87 on their designated latent factors. In the autonomous subscale, items emphasizing personal health value (e.g., Item 1, Item 3) and life congruence (Item 6, Item 11) yield standardized loadings exceeding .75. Controlled items split into external pressures (Item 4, Item 9) and introjected guilt/shame (Item 2, Item 7), yet converge reliably onto a higher-order controlled motivation factor with loadings exceeding .58. Multi-group CFA further confirmed full metric and structural invariance across demographic subdivisions, including gender, age groups, and baseline smoking severity, confirming that the measurement parameters are comparable across diverse populations.

10. Instrument / Measurement Tool

The following technical specifications define the structure, format, and scoring rules for the Treatment Self-Regulation Questionnaire (TSRQ) within the Health-Care SDT Packet:

• Instrument Type: Standardized self-report psychometric rating questionnaire.
• Target Population: Clinical and non-clinical adults and adolescents facing health behavior decisions, entering medical regimens, or participating in lifestyle modifications.
• Administration Format: Self-administered paper-and-pencil questionnaire, clinician-assisted structured interview, or secure online digital survey.
• Item Count: 15 items across three subscales (an 8-item short form comprising 4 autonomous and 4 controlled items has also been used in earlier literature).
• Response Scale: 7-point Likert-type scale formatted as follows:
  • 1: Not at all true
  • 2: (Unlabeled intermediate anchor)
  • 3: (Unlabeled intermediate anchor)
  • 4: Somewhat true
  • 5: (Unlabeled intermediate anchor)
  • 6: (Unlabeled intermediate anchor)
  • 7: Very true
• Subscale Item Breakdown (15-Item Version):
  • Autonomous Motivation Subscale: Items 1, 3, 6, 8, 11, and 13.
  • Controlled Motivation Subscale: Items 2, 4, 7, 9, 12, and 14.
  • Amotivation Subscale: Items 5, 10, and 15.
• Scoring Procedures:
  • Autonomous Score: Calculate the arithmetic mean of items 1, 3, 6, 8, 11, and 13 (sum of raw scores divided by 6). Range: 1.00 to 7.00.
  • Controlled Score: Calculate the arithmetic mean of items 2, 4, 7, 9, 12, and 14 (sum of raw scores divided by 6). Range: 1.00 to 7.00.
  • Amotivation Score: Calculate the arithmetic mean of items 5, 10, and 15 (sum of raw scores divided by 3). Range: 1.00 to 7.00.
  • Relative Autonomy Index (RAI) / Relative Autonomous Motivation Index (RAMI): When a single composite score is required, calculate the difference between the autonomous and controlled mean scores:
    RAI = Autonomous Mean - Controlled Mean
    Positive values signify predominantly autonomous self-regulation, whereas negative values reflect predominantly controlled behavioral regulation. (Note: Researchers frequently utilize the subscales as separate predictors in multivariate modeling rather than combining them, preserving distinct variance).
• Associated Packet Instruments:
  • Perceived Competence Scale (PCS): 4 items scored as a single mean composite (Range: 1.00 to 7.00).
  • Health Care Climate Questionnaire (HCCQ): 6-item short form (or 15-item full form) scored as a single mean composite representing perceived provider autonomy support (Range: 1.00 to 7.00).

11. Permissions & Fee and Test Year

The instruments within the Health-Care, Self-Determination Theory Packet were developed across several collaborative investigations beginning in the mid-1990s (Williams et al., 1996; Ryan, Plant, & O’Malley, 1995) and formally consolidated and validated as a dedicated health packet by Geoffrey C. Williams, Richard M. Ryan, and Edward L. Deci (Williams et al., 1998, 1999; Levesque et al., 2007).

In accordance with the open-science principles maintained by the Center for Self-Determination Theory (CSDT), the instruments (including the TSRQ, PCS, and HCCQ across all target behavioral variations) are made available free of charge for academic, educational, non-commercial research, and clinical diagnostic applications. Researchers and clinicians may download, adapt for specific health targets, and utilize these scales without explicit written permission or licensing fees, provided that appropriate scholarly attribution is maintained in subsequent publications and reports. Commercial organizations, pharmaceutical sponsors, or for-profit digital health platforms wishing to integrate the scales into commercial software or proprietary clinical trials are directed to contact the Center for Self-Determination Theory to obtain commercial licensing arrangements.

12. References

The following publications document the theoretical foundation, psychometric validation, and clinical application of the Health-Care Self-Determination Theory Packet:

• 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
• 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 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., 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., Dozier, A. 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 attendance in methadone maintenance therapy. Journal of Substance Abuse Treatment, 27(3), 197–201. https://doi.org/10.1016/j.jsat.2004.07.001

13. Items of the Scale