Introduction
The Leeds Dependence Questionnaire (LDQ), developed in 1994 by Raistrick et al., stands as a significant tool for screening and measuring the severity of substance dependence. Impressively, it effectively captures the “graded intensity” of dependence across psychoactive substances like alcohol, opioids, and stimulants; moreover, it is notably sensitive to treatment-related changes.
Its academic credibility is evident, with key validation studies cited over 400 times, the LDQ is undoubtedly a well-regarded instrument in clinical and research settings. Consequently, this guide explores the LDQ’s features, applications, and overall importance in assessing substance dependence.
Key Features of the Leeds Dependence Questionnaire (LDQ)
Purpose and Use
The primary purpose of the LDQ involves measuring the severity of substance dependence. Specifically, it achieves this by assessing behavioral and cognitive patterns associated with dependence. As a result, the LDQ serves as an indicator of how addicted a person is and, therefore, can help predict the difficulty in achieving positive treatment outcomes. This, in turn, makes it an essential tool for both initial screening and longitudinal research to monitor changes in dependence levels.
Questionnaire Details
Regarding its structure, the LDQ consists of 10 questions. These questions aim to assess various behavioral and cognitive patterns indicative of dependence on substances and substance use disorders. Furthermore, the responses operate on a Likert scale, thereby allowing for a nuanced measurement of dependence severity.
The LDQ primarily falls within the domain of psychology. More specifically, its sub-domains focus on the behavioral and cognitive patterns of dependence on substances, which aligns with criteria for substance use disorders.
Target Population
In terms of its intended users, clinicians and researchers can utilize the LDQ for adults aged 18 years and above. This specifically includes young adults (18-24 years), middle-aged adults (25-44 years), older adults (45-64 years), and seniors (65+ years). Moreover, it particularly targets adults with alcohol, heroin, methadone, and stimulant dependence.
Languages Available
Originally developed in English, the LDQ has subsequently been translated into several other languages to facilitate its global use. For example, available languages include Arabic, Mandarin Chinese, Spanish, French, German, Portuguese, Italian, and Romanian. This multilingual availability significantly enhances its applicability in diverse international research and clinical contexts.
Cost, Licensing, and Administration of the LDQ
The LDQ is free for academic and clinical use. It operates under an open access license type, ensuring broad availability for non-commercial purposes. However, users should note that permission may be required for redistribution. This general freeness, nonetheless, promotes its widespread adoption.
Administration Time and Format is another practical strength of the LDQ.
The questionnaire developers designed it for quick completion, as it typically takes less than 5 minutes. Moreover, it can be administered in various formats, including paper-based, digital (online), interview (in-person), and via phone/video call, thus offering flexibility for diverse settings. Encouragingly, no special training is required for its administration because individuals can self-administer it.
Scoring Method
The LDQ employs a straightforward scoring method that professionals can easily apply. Specifically, they score each of its 10 items from 0 (“Never”) to 3 (“Nearly always”). This results in a total score ranging from 0 to 30. Importantly, a higher score signifies more severe substance dependence; indeed, it’s best to view substance dependence as a continuum where higher scores indicate stronger dependence and greater difficulty in reducing substance use.
Generally, the interpretation of scores is as follows:
- Low dependence: Scores of 10 or less (for males, clinicians often consider this low; for females, 5 or less; if gender is unspecified, they use 8 or less cautiously).
- Moderate dependence: Scores between 11 (or 6 for females, or 9 if unspecified) and 20.
- High dependence: Scores above 20. Additionally, pro-rated scoring is allowed if two or fewer items are missing. Functional population thresholds are also suggested, with males <10 and females <5 indicating lower dependence.
Clinical Utility and Applications
The LDQ offers significant utility in various clinical and research settings, demonstrating its versatility.
- Screening: Firstly, it effectively identifies individuals whose substance use may indicate dependence.
- Monitoring: Secondly, the questionnaire is invaluable for tracking changes in dependence severity over time, particularly in response to treatment interventions.
- Treatment Planning: Thirdly, by quantifying the level of dependence, the LDQ assists clinicians in developing tailored treatment strategies.
- Research: Lastly, it is widely used in research studies, especially those evaluating the effectiveness of treatments for substance use disorders, thereby making it a key instrument in evidence-based addiction science.
Reliability and Validity
Experts recognize the LDQ as a highly reliable and valid instrument for measuring dependence. For instance, it boasts a strong Cronbach’s alpha of 0.94, indicating excellent internal consistency. Furthermore, its test-retest reliability is very high at 0.95.
Numerous studies reinforce its psychometric strength across various substances, including:
- Original Validation Study (1994): Published in Addiction, this foundational study established the LDQ’s reliability and validity. View Study
- Cocaine Dependence Study: This research validated the LDQ’s effectiveness for assessing cocaine dependence, further proving its versatility. View Study
- Italian Adaptation Study: An Italian version of the LDQ was validated, confirming its applicability across diverse populations. View Study
These studies, among others, solidify the LDQ’s robustness and global utility, making it an essential tool for addiction research and clinical practice.
Limitations and Considerations
Despite its many strengths, the LDQ does have a few limitations that users should consider:
- Self-report measure: Responses may be subject to biases inherent in self-reporting.
- Cultural Bias: Validation has occurred primarily in Caucasian samples, which may necessitate cultural adaptation for other populations.
- Language Barriers: Although translated, not all languages are covered, potentially limiting its use in some regions.
- Social Desirability Bias: Respondents might underreport the extent of their substance use or dependence to present themselves more favorably.
Other Versions and Adaptations
It is also useful to know that modified versions of the LDQ exist, for example:
- For medication-overuse headache (MOH).
Additionally, related questionnaires that measure similar or complementary constructs include:
- Severity of Dependence Scale (SDS)
- Alcohol Dependence Scale (ADS)
- Fagerström Test for Nicotine Dependence (FTND)
The LDQ is also noted as suitable for use during periods of abstinence. One platform offering a version is NovoPsych.
Additional Resources
- Original validation study
- Access the questionnaire as a PDF
- For access and inquiries, refer to the following contact points and platforms.
- Addiction Journal Contact: orgaddictionjournal.org
- Publisher: Wiley Online Library
- LDQ Platforms:
- NovoPsych (Australia/Global)
- Greenspace Health (US/Canada)
- For additional LDQ resources, consult Oxford University Press
Frequently Asked Questions (FAQ)
- Who can use the LDQ?
Researchers, clinicians, and healthcare providers can utilize the LDQ for adults (18 years and older) with suspected or known substance dependence, including on alcohol, opioids, and stimulants. - How long does it take to complete the LDQ?
The LDQ is very brief; indeed, an individual typically requires less than 5 minutes to complete it. - How is the LDQ scored?
Each of the 10 questions receives a score on a 0-3 Likert scale, with total scores consequently ranging from 0 to 30. Higher scores indicate greater dependence severity, and specific cut-offs help categorize dependence as low, moderate, or severe. - Is there any cost to using the LDQ?
The LDQ is free for clinical and research use. However, users may need permission for redistribution.
A Word From ResRef
The LDQ is a robust, versatile tool for assessing dependence severity. Its strong psychometric properties and adaptability make it invaluable for both clinical practice and research, though cultural adaptations may enhance its global applicability.
References
- RAISTRICK, D., BRADSHAW, J., TOBER, G., WEINER, J., ALLISON, J. and HEALEY, C. (1994), Development of the Leeds Dependence Questionnaire (LDQ): a questionnaire to measure alcohol and opiate dependence in the context of a treatment evaluation package. Addiction, 89: 563-572. (link)
- Kelly JF, Magill M, Slaymaker V, Kahler C. Psychometric validation of the Leeds Dependence Questionnaire (LDQ) in a young adult clinical sample. Addict Behav. 2010 Apr;35(4):331-6. doi: 10.1016/j.addbeh.2009.11.005. Epub 2009 Dec 3. PMID: 20004062; PMCID: PMC3773982. (link)
- Heather, N., Raistrick, D., Tober, G., Godfrey, C., & Parrott, S. (2001). Leeds Dependence Questionnaire: New Data from a Large Sample of Clinic Attenders. Addiction Research & Theory, 9(3), 253–269. (link)
