Strengths and Difficulties Questionnaire (SDQ) – self-completion

Abstract

The Strengths and Difficulties Questionnaire (SDQ) is a widely utilized, brief screening tool designed to assess the emotional, behavioral, and relational adjustment of children and young people. The self-completion version, specifically tailored for adolescents, comprises 25 items that measure five key areas: four scales focused on difficulties (Emotional Symptoms, Conduct Problems, Hyperactivity/Inattention, and Peer Relationship Problems) and one scale focused on strengths (Prosocial Behaviour). The instrument also incorporates an essential impact supplement to determine the clinical significance of the reported difficulties, making it valuable for epidemiological studies and clinical practice in identifying potential cases of psychopathology.

Keywords

SDQ, Strengths and Difficulties Questionnaire, Child Assessment, Adolescent Mental Health, Behavioral Screening, Prosocial Behavior, Emotional Symptoms, Psychopathology.

Authors

Robert Goodman, Howard Meltzer, Virginia Bailey.

Purpose

The primary purpose of the SDQ self-completion version is to efficiently screen large populations of young people for emotional and behavioral problems, allowing for the rapid identification of individuals who may require further comprehensive diagnostic assessment or intervention. By focusing both on deficits (difficulties) and positive attributes (strengths), the scale offers a balanced perspective on the young person’s overall psychological adjustment.

A crucial component is the impact supplement, which moves beyond symptom counting to assess the extent to which reported difficulties cause personal distress, impede daily functioning across various environments (home, school, leisure), and create burdens for those around the respondent. This helps clinicians and researchers distinguish between subclinical symptom levels and those that reach the threshold of clinical significance.

Construct

The Strengths and Difficulties Questionnaire is structured around a five-factor model of psychological adjustment. Each factor is measured by five specific items, totaling 25 items, which collectively contribute to scores reflecting both internalizing and externalizing problems, as well as positive social functioning.

• Emotional Symptoms: Reflects internalizing distress, including anxiety, depressive mood, and somatic complaints (e.g., worries, unhappiness).
• Conduct Problems: Reflects externalizing behaviors and rule violations (e.g., fighting, lying, temper loss).
• Hyperactivity/Inattention: Reflects attention deficits and motor restlessness (e.g., fidgeting, poor concentration).
• Peer Relationship Problems: Reflects difficulties in social integration, isolation, and victimization (e.g., being bullied, having few friends).
• Prosocial Behaviour: Reflects positive social engagement, empathy, and helpfulness (e.g., being kind, sharing).

Validity

The self-report version of the SDQ has demonstrated robust validity across numerous international studies. Concurrent validity is supported by its strong correlations with established, longer measures of child psychopathology, such as the Child Behavior Checklist (CBCL) and diagnostic interviews. The scale effectively discriminates between young people referred to mental health services and those drawn from the general population, confirming its utility as a screening tool.

Construct validity is evidenced by the clear differentiation between the four difficulty scales and the Prosocial scale, reflecting the distinction between negative and positive aspects of adjustment. Furthermore, the inclusion of the impact supplement significantly increases the predictive validity for identifying clinical caseness, as functional impairment is a critical component of psychiatric diagnosis.

Reliability

The reliability of the SDQ is generally strong for the composite scores. The Total Difficulties score (sum of the four problem scales) typically exhibits good internal consistency, with Cronbach’s alpha coefficients routinely falling above 0.70, validating its use as a measure of overall psychological distress in adolescents.

While the internal consistency for the individual five-item subscales can sometimes be lower (as is common with very brief scales), they remain acceptable for screening purposes. Test-retest reliability studies have confirmed the stability of the scores over short periods, indicating that the instrument provides consistent measurement of stable behavioral and emotional characteristics in young people.

Factor Analysis

The theoretical foundation of the Strengths and Difficulties Questionnaire rests on a five-factor structure, which aligns with common clinical conceptualizations of child and adolescent problems. Multiple Confirmatory Factor Analysis (CFA) studies have been conducted globally to test this structure across various cultural and linguistic groups. While the five-factor model is generally supported and used for standard scoring, research (e.g., Goodman et al., 2010) occasionally suggests that a broader, secondary structure comprising Internalizing (Emotional Symptoms and Peer Problems) and Externalizing (Conduct Problems and Hyperactivity) factors, along with the separate Prosocial factor, also provides a statistically acceptable fit, particularly when seeking broader clinical classifications.

Instrument

Test Type: Psychometric Screening tool for behavioral and emotional problems.

Format: Self-report questionnaire (25 items plus an impact supplement). Items are scored on a 3-point Likert scale: Not True, Somewhat True, Certainly True.

Language Available: Translated and validated into over 80 languages worldwide.

Population Group: Children and young people (Self-completion version is for older youth).

Age Group: Typically 11 to 17 years old.

Population Details: Used extensively in clinical, educational, and general community settings to screen for high-risk individuals.

Test Methodology: Can be administered via paper-and-pencil, computer, or tablet. Scoring involves deriving five subscale scores, a Total Difficulties score (sum of the four difficulty scales), and an impairment score from the impact supplement questions.

Keywords

Emotional Symptoms, Conduct Problems, Hyperactivity, Peer Problems, Prosocial Behavior, Clinical Impairment, Total Difficulties Score, Adolescent Assessment, Adolescence.

Authors

Author ORCID Identifier: N/A (Information not provided in source).

Affiliation Email addresses: N/A (Information not provided in source).

Correspondence Address: N/A (Information not provided in source).

Permissions & Fee and Test Year

The Strengths and Difficulties Questionnaire (SDQ) is available free of charge for non-commercial academic research and clinical use in most languages. Formal permission is required for any commercial application or modification of the scale. The initial pilot study validating the self-completion version of the instrument was published in 1998 by Goodman, Meltzer, and Bailey.

Reference’s

Goodman R (1997) The Strengths and Difficulties Questionnaire: A Research Note. Journal of Child Psychology and Psychiatry, 38, 581-586.

Goodman R, Meltzer H, Bailey V (1998) The Strengths and Difficulties Questionnaire: A pilot study on the validity of the self-report version. European Child and Adolescent Psychiatry, 7, 125-130.

Goodman R (1999) The extended version of the Strengths and Difficulties Questionnaire as a guide to child psychiatric caseness and consequent burden. Journal of Child Psychology and Psychiatry, 40, 791-801.

Goodman A, Lamping DL, Ploubidis GB (2010) When to use broader internalising and externalising subscales instead of the hypothesised five subscales on the Strengths and Difficulties Questionnaire (SDQ): data from British parents, teachers and children. Journal of Abnormal Child Psychology, 38, 1179-1191.

Items of the Strengths and Difficulties Questionnaire (SDQ) – self-completion

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The original questionnaire and scoring details can be found at: http://www.sdqinfo.com/py/sdqinfo/b3.py?language=Englishqz(USA)

Response Options: Not True, Somewhat True, Certainly True

1. I try to be nice to other people. I care about their feelings
2. I am restless, I cannot stay still for long
3. I get a lot of headaches, stomach-aches or sickness
4. I usually share with others, for example CD’s, games, food
5. I get very angry and often lose my temper
6. I would rather be alone than with people of my age
7. I usually do as I am told
8. I worry a lot
9. I am helpful if someone is hurt, upset or feeling ill
10. I am constantly fidgeting or squirming
11. I have one good friend or more
12. I fight a lot. I can make other people do what I want
13. I am often unhappy, depressed or tearful
14. Other people my age generally like me
15. I am easily distracted, I find it difficult to concentrate
16. I am nervous in new situations. I easily lose confidence
17. I am kind to younger children
18. I am often accused of lying or cheating
19. Other children or young people pick on me or bully me
20. I often offer to help others (parents, teachers, children)
21. I think before I do things
22. I take things that are not mine from home, school or elsewhere
23. I get along better with adults than with people my own age
24. I have many fears, I am easily scared
25. I finish the work I’m doing. My attention is good

Do you have any other comments or concerns?

Overall, do you think that you have difficulties in any of the following areas: emotions, concentration, behavior or being able to get on with other people?

No, Yes minor difficulties, Yes definite difficulties, Yes severe difficulties

If you have answered “Yes”, please answer the following questions about these difficulties:

• How long have these difficulties been present? Less than a month, 1-5 months, 6-12 Months, Over a year
• Do the difficulties upset or distress you? Not at all, Only a little, A medium amount, A great deal
• Do the difficulties interfere with your everyday life in the following areas?

HOME LIFE: Not at all, Only a little, A medium amount, A great deal

FRIENDSHIPS: Not at all, Only a little, A medium amount, A great deal

LEARNING: Not at all, Only a little, A medium amount, A great deal

LEISURE ACTIVITIES: Not at all, Only a little, A medium amount, A great deal

• Do the difficulties make it harder for those around you (family, friends, teachers, etc.)? Not at all, Only a little, A medium amount, A great deal