The Strengths and Difficulties Questionnaire: A Research Note

Transcription

1 J. Child Psychol. Psychiat. Vol, 38. No, 5, pp , 1997 Cambridge Uiversity Press 1997 Associatio for Child Psychology ad Psychiatry Prited i Great Britai, All rights reserved /97 $ ,00 The Stregths ad ifficulties Questioaire: A Research Note Robert Goodma Istitute of Psychiatry, Lodo, U.K. A ovel behavioural screeig questioaire, the Stregths ad ifficulties Questioaire (SQ), was admiistered alog with Rutter questioaires to parets ad teachers of 403 childre draw from detal ad psychiatric cliics. Scores derived from the SQ ad Rutter questioaires were highly correlated; paret-teacher correlatios for the two sets of measures were comparable or favoured the SQ. The two sets of measures did ot differ i their ability to discrimiate betwee psychiatric ad detal cliic atteders. These prelimiary fidigs suggest that the SQ fuctios as well as the Rutter questioaires while offerig the followig additioal advatages: a focus o stregths as well as difficulties; better coverage of iattetio, peer relatioships, ad prosocial behaviour; a shorter format; ad a sigle form suitable for both parets ad teachers, perhaps thereby icreasig paret-teacher correlatios. Keywords: Questioaire, child behaviour, psychopathology, stregths. Abbreviatios: CBCL: Child Behavior Checklist; ROC: Receiver Operatig Characteristic; SQ: Stregths ad ifficulties Questioaire. impulsivity-reflectiveess, havig frieds, beig victimised, ad actig prosocially are poorly covered. Fially, whereas oe versio of the Achebach questioaire is desiged for completio by youg people themselves (Achebach, 1991b), there is o equivalet Rutter questioaire for self-completio. A previous research ote (Goodma, 1994) described a expaded Rutter paret questioaire that icorporated all of the origial Rutter items as well as may additioal items, mostly o childre's stregths. The iclusio of these additioal items did ot appear to atteuate the valuable properties of the origial Rutter questioaire as a behaviour screeig istrumet, though the extra items presumably did make the questioaire somewhat more time-cosumig to complete. Factor aalyses suggested that amog childre of ormal itelligece the expaded questioaire was tappig five distict dimesios; coduct problems, emotioal symptoms, hyperactivity, peer problems, ad prosocial behaviour. Usig these fidigs as a guide, the SQ was desiged to meet the followig specificatios; it should fit easily o oe side of paper; it should be applicable to childre ad youg people ragig from 4 to 16 years; the same versio should be completed by parets ad teachers; a similar versio should be available for self-report; both stregths ad difficulties should be well represeted; ad there should be equal umbers of items o each of five relevat dimesios, amely coduct problems, emotioal symptoms, hyperactivity, peer relatioships, ad prosocial behaviour. This paper compares iformatcompleted SQs with Rutter paret ad teacher questioaires. Itroductio This paper describes a brief behavioural screeig questioaire that provides balaced coverage of childre ad youg people's behaviours, emotios, ad relatioships. The value of this ovel Stregths ad ifficulties Questioaire (SQ) is evaluated agaist the bechmark set by the Rutter paret ad teacher questioaires. The SQ has bee desiged to meet the eeds of researchers, cliicias, ad educatioalists. The Rutter questioaires are log-established ad highly respected behavioural screeig questioaires that have proved valid ad reliable i may cotexts (Elader & Rutter, 1996). Though substatially shorter ad therefore quicker to complete tha the Child Behavior Checklist (CBCL; Achebach, 1991a), the Rutter paret questioaire seem o less useful for may purposes (Berg, Lucas, & McGuire, 1992; Elader & Rutter, 1995; Fomboe, 1989). eveloped three decades ago, the Rutter questioaires have geerally wor well, though they do show their age i some ways. Thus all items are about udesirable traits whereas the recet tred, particularly i educatio, has bee to emphasise childre's stregths ad ot just their deficits. I additio, the rage of behavioural items covered by the Rutter questioaires is ow somewhat dated. Thus ail-bitig ad thumb-suckig are icluded whereas may areas of cotemporary iterest icludig cocetratio, Requests for reprits, or sample questi^paires (available i may laguages), to: r. R. Goodma, epartmet of Child ad Adolescet Psychiatry, Istitute of Psychiatry, e Crespigy Park, Lodo SE5 8AF, U.K. 581

2 R. GOOMAN 5S2 Materials ad Methods Samplig Questioaires were obtaied o 403 childre aged 4-16 years attedig oe of two Lodo child psychiatric cliics or the childre's departmet of a Lodo detal hospital. The parets of childre attedig these cliics were recruited ito the study util a plaed total of roughly childre had bee attaied for both detal ad psychiatric samples. I the detal cliic ad oe of the psychiatric cliics (Cliic A), parets who had give iformed coset were asked to complete two behavioural screeig questioaires while awaitig their cliic appoitmet. Participatig parets were subsequetly asked for permissio for their child's teacher to be approached o a similar basis. The other psychiatric cliic (Cliic B) routiely used questioaires prior to the first assessmet, sedig them to all parets ad, whe permissio was obtaied, to teachers as well. I this cliic, parets were routiely set both behavioural screeig questioaires ad asked if they would be willig for their aswers (ad the teacher's aswers) to be used ot oly for cliical purposes but also for research. Some of the parets from Cliic B did ot complete questioaires themselves but did give permissio for teacher questioaires to be used for research. The proportio of refusals was ot systematically recorded sice, as explaied later, the statistical aalyses did ot require the samples to be represetative. Methods Respodets were admiistered a Rutter questioaire ad a Stregths ad ifficulties Questioaire (SQ) i radomised order. Parets were give the Rutter A(2) Questioaire ad teachers the Rutter B(2) Questioaire; both were scored i the stadard way to geerate scores for total deviace, coduct problems, emotioal symptoms, ad hyperactivity (Rutter, 1967; Rutter, Tizard, & Whitmore, 1970; Schachar, Rutter, & Smith, 1981). The iformat-rated versio ofthe SQ was admiistered to both parets ad teachers. This versio of the SQ is reproduced i full i Appedix A for iformatio oly. The SQ asks about 25 attributes, 10 of which would geerally be thought of as stregths, 14 of which would geerally be thought of as difficulties, ad oe of which " gets o better with adults tha with other childre" is eutral. Though o SQ item is idetically worded to ay Rutter item, five items are similarly worded. The iitial choice of items was guided by the factor loadigs ad frequecy distributios that had previously bee obtaied o a expaded Rutter paret questioaire (Goodma, 1994); items were subsequetly modified ad amalgamated o the basis of a successio of iformal trials as well as advice from colleagues. The 25 SQ items are divided betwee 5 scales of 5 items each, as show below. Hyperactivity Scale. " Restless, overactive, caot stay still for log"; "Costatly fidgetig or squirmig"; "Easily distracted, cocetratio waders"; ' 'Thiks thigs out before actig"'; ad ""Sees tasks through to the ed, good attetio spa''. Emotioal Symptoms Scale. "Ofte complais of headaches, stomach-ache or sickess"; "May worries, ofte seems worried"; "Ofte uhappy, dow-hearted or tearful"; "Nervous or cligy i ew situatios, easily loses cofidece"; ad "May fears, easily scared". Coduct Problems Scale. "Ofte has temper tatrums or hot tempers"; ""Geerally obediet, usually does what adults request''; "Ofte fights with other childre or bullies them"; "Ofte lies or cheats"; ad "Steals from home, school or elsewhere". Peer Problems Scale. "Rather solitary, teds to play aloe"; "'Has at least oe good fried"; ''Geerally liked by other childre"; "Picked o or bullied by other childre"; ad "Gets o better with adults tha with other childre". Prosocial Scale. " Cosiderate of other people's feeligs "; "Shares readily with other childre (treats, toys, pecils, etc.)"; "Helpful if someoe is hurt, upset or feelig ill"; "Kid to youger childre"; ad "Ofte voluteers to help others (parets, teachers, other childre)". Each item ca be marked "ot true", "somewhat true" or "certaily true". For all of the items except the five prited above i italics, the item is scored 0 for "ot true", 1 for " somewhat true", ad 2 for "certaily true". For the five items prited above i italics, the item is scored 2 for " ot true ", 1 for "somewhat true", ad 0 for "certaily true". The score for each ofthe five scales is geerated by summig the scores for the five items that make up that scale, thereby geeratig a scale score ragig from 0 to 10. The scores for hyperactivity, emotioal symptoms, coduct problems, ad peer problems ca be summed to geerate a total difficulties score ragig from 0 to 40; the prosocial score is ot icorporated i the reverse directio ito the total difficulties score sice the absece of prosocial behaviours is coceptually differet from the presece of psychological difficulties. The Rutter A(2) ad the SQ were both completed by the parets of 346 childre: 158 detal cliic atteders ad 188 psychiatric cliic atteders. The Rutter B(2) ad the SQ were both completed by the teachers of 185 childre: 39 detal cliic atteders ad 146 psychiatric cliic atteders. Most of the teacher reports were o psychiatric cliic atteders because the parets of childre attedig Child Psychiatric Cliic B geerally agreed to the cliic sedig questioaires to teachers for cliical as well as research purposes; parets of childre attedig the detal cliic or Child Psychiatric Cliic A were less likely to give permissio for teacher questioaires to be obtaied solely for research purposes. Statistical Aalysis As i previous studies comparig the validity of differet screeig questioaires (e.g. Berg et a l, 1992), aalyses of Receiver Operatig Characteristic (ROC) curves were used to establish how well each questioaire was able to distiguish betwee high- ad low-risk samples, determiig the area uder the curve for each questioaire (Haley & McNeil, 1982). For this purpose, the oly uderlyig assumptio is that childre recruited from the two psychiatric cliics were substatially more likely to have psychiatric disorders tha childre recruited from the detal cliic. There is o assumptio that all subjects recruited from the psychiatric cliics had psychiatric disorders, or that all subjects recruited from the detal cliic were free from psychiatric disorder. Equally, there is o assumptio that the psychiatric sample was represetative of all childre betwee 4 ad 16 who atted psychiatric cliics, or that the detal sample was represetative of all childre attedig detal cliics, let aloe of all childre aged betwee 4 ad 16. Sice the ROC curves for the SQ ad Rutter questioaires were derived from the same set of patiets, the statistical compariso of the areas uder these ROC curves allowed for the paired ature ofthe data (Haley & McNeil, 1982). Compariso ofthe paret-teacher correlatios of the SQ ad Rutter questioaires also allowed for the paired ature of the data, usig structural equatio modellig (EQS, BMP Statistical Software) ad examiig whether costraiig the two correlatios to be the same resulted i a sigificatly poorer fit. Though appropriate for tests of comparative validity ad crosssituatio correlatio, the case-cotrol samplig used i this study does ot geerate sesitivity or specificity estimates that

3 STRENGTHS AN IFFICULTIES QUESTIONNAIRE could securely be geeralised to represetative epidemiological or cliical samples; such estimates will subsequetly be derived from other studies i progress. Reported correlatios are Pearso product-momet correlatios, but the patter of fidigs was ot chaged whe Spearma correlatios were used istead. Itraclass correlatios which are ofte appropriate for reliability estimates were ot used to measure paret-teacher agreemet eve though this agreemet could be costrued as a idex of iter-rater reliability. Parets ad teachers make ratigs based o differet sources of iformatio, whereas measures of iterrater reliability are more appropriately derived from idepedet ratigs based o the same source of iformatio. Furthermore, employig itraclass correlatios would have ivolved mixig paret- ad teacher-derived scores, ad this would have bee iappropriate sice mea scores differed systematically betwee paret ad teacher ratigs a differece allowed for whe iterpretig these scores (Rutter, 1967; Rutter et al., 1970; ad see Appedix B). 583 Sesitivity 1-1 _:_^:-.;-'* 0.8- / ' 0.6- / T J -^SQ Results Rutter I 1 Age ad Geder 0 The mea age {S) ofthe detal sample was 10.8 years (3.1) while that ofthe psychiatric sample was 9.8 years (3.3), a sigificat differece [t (401) = 3.00, /? <.01]. As expected, the proportio of males was higher i the psychiatric sample (63%, 153/244) tha i the detal sample (53%, 85/159) [cotiuity-adjusted/ (1) = 3.03, p <.05, 1-tailed]. The results reported here are for the sample as a whole, though closely similar results were obtaied whe ROC ad correlatioal aalyses were repeated separately for boys ad girls, ad separately for childre aged 4-10 ad Sesitivity Specificity Pigure 2. ROC curves for teacher-rated questioaires. iscrimiatig betwee Psychiatric ad Nopsychiatric Samples The ability of the two questioaires to distiguish betwee detal ad psychiatric cases is reflected i the Receiver Operatig Characteristic (ROC) curves show i Figs. 1 ad 2 for paret ad teacher reports respectively. The ROC curves for the Rutter questioaires are based o total deviace scores, whereas the SQ curves are based o total difficulties scores. The comparable ability of the two measures to discrimiate betwee the two samples is evidet from the extet to which the two curves almost superimpose o oe aother. Quatitatively, this comparability ca be judged from the area uder each ofthe curves, which is a measure of how well that measure discrimiates betwee the two samples; the area uder the curve would be 1.0 for a measure that discrimiated perfectly, ad.5 for a measure that discrimiated with o better tha chace accuracy. For paret reports, the area uder the curve (95 % cofidece iterval) was.87 ( ) for the SQ as compared with.87 ( ) for the Rutter A(2) paret questioaire a osigificat differece (z =.13, p =.9). For teacher reports, the correspodig values were.85 ( ) for the SQ as compared with.84 ( ) for the Rutter B(2) teacher questioaire a osigificat differece (2 =.41,;; =.7) SQ-Rutter Specificity 0.8 Pigure 1. ROC curves for paret-rated questioaires. Correlatios Table 1 shows the correlatios betwee SQ ad Rutter scores. The correlatios were oly margially lower whe the aalyses were repeated for the detal ad psychiatric samples separately. No cross-measure corre-

4 R. GOOMAN 584 Table 1 Iter-measure Correlatio for Each Type of Rater SQ-Rutter correlatio Total eviace/ifficulties score Coduct Problems score Emotioal Symptoms score Hyperactivity score Table 2 Iter-rater Correlatios for Each Type of Measure Paret-Teacher correlatio (N == 128) Total eviace/ifficulties score Coduct Problems score Emotioal Symptoms score Hyperactivity score Peer Problems score Prosocial Behaviour score SQ Rutter.62* * Correlatio sigificatly higher tha the comparable Rutter correlatio (p <.02); all other comparisos osigificat. latios ca be preseted o two SQ scores the peer problems score ad the prosocial behaviour score sice they have o Rutter couterpart. Paret-Teacher Correlatios Table 2 presets the correlatio coefficiets betwee teacher- ad paret-derived scores whe both are usig the SQ or whe both are usig Rutter questioaires. For comparable scores, the cross-situatio correlatios of the SQ ad Rutter measures were geerally similar, apart from the higher SQ correlatio for total score \X^ (1) = 5.90, p <.02]. Though the correlatios were lower whe the aalyses were repeated for the detal ad psychiatric samples separately, these correlatios were geerally comparable for the SQ ad Rutter measures, apart from a higher SQ correlatio for total score i the psychiatric sample [x^ (1) = 4.05, p <.05). iscussio Give the well-established validity ad reliability ofthe Rutter questioaires (Elader & Rutter, 1996), the high correlatio betwee the total scores geerated by the SQ ad Rutter questioaires is evidece for the cocurret validity of the SQ. Paret-teacher correlatios were either equivalet for the two measures or slightly favoured the SQ, perhaps because the SQ Paret report Teacher report A^= used idetical items for parets ad teachers whereas the Rutter questioaires were somewhat differet for parets ad teachers. The ROC aalyses showed that the two measures had equivalet predictive validity, as judged by their ability to distiguish betwee psychiatric ad opsychiatric samples. Of course, discrimiatig betwee psychiatric ad detal cliic atteders is a relatively easy task, but the high correlatio betwee SQ ad Rutter scores withi each cliic group suggests that the two measures are also likely to be comparably discrimiatig i more demadig screeig tasks, such as detectig oreferred cases of child metal health problems i the commuity; further empirical studies would be eeded to cofirm this. Sice previous studies have show that CBCL ad Rutter paret questioaire scores are highly correlated (Berg et al., 1992; Fomboe, 1989), ad that these two sets of questioaires are of comparable predictive vahdity (Berg et al., 1992), it is likely that the SQ ad CBCL will also be highly correlated ad have comparable validity; direct comparisos are curretly uder way. The SQ ad Rutter questioaires ca each be used to geerate separate scores for coduct problems, emotioal symptoms, ad hyperactivity. For each of these three scores, there was a high correlatio betwee the SQ score ad the Rutter score; ad paret-teacher correlatios were comparable for the two sets of measures. espite its brevity, the SQ also geerated two scores that have o Rutter couterparts; a peer problems score ad a prosocial behaviour score. The performace of the SQ could potetially have bee udermied by three of its desig features; iclusio of stregths as well as difficulties; use of a idetical questioaire for both parets ad teachers; ad a compact presetatio o just oe side of paper. The equivalece of the SQ ad Rutter scores suggests that these three features have ot had a adverse effect. This should ecourage researchers ad cliicias who are cotemplatig icorporatig similar features ito other questioaires. Rutter questioaires are routiely used to categorise childre as likely psychiatric "cases" or "o-cases" accordig to whether their total deviace score is equal to or greater tha a stadard cut-off; 13 o the Rutter paret questioaire ad 9 o the Rutter teacher questioaire (Rutter, 1967; Rutter et al., 1970). Usig a sigle cut-off for all studies has both advatages ad disadvatages. The advatages are simplicity ad equivalece across studies. The mai disadvatage is that "caseess" does ot have a comparable meaig i

5 STRENGTHS AN IFEICULTIES QUESTIONNAIRE differet studies simply because those studies have employed the same cut-off. Comparability is particularly likely to be lost whe high- ad low-risk samples are cotrasted. A worked example may be helpful. Study X ivolves 100 childre from a high-risk populatio with a true rate of psychiatric disorder of 50 %; if the screeig questioaire has a sesitivity of.8 ad a specificity of.8 whe usig the stadard cut-off, the questioaire will idetify 40 true positives ad 10 false positives. Study Y ivolves 100 childre from a low-risk populatio with a true rate of disorder of 10%; eve with the same sesitivity ad specificity, the questioaire will idetify 8 true positives ad 18 false positives. espite usig the same questioaire ad the same cut-off, a compariso of "cases" from studies X ad Y will primarily be a compariso of true positives from study X with false positives from study Y. Give these problems, the best strategy for researchers may be to choose cut-offs accordig to the likely disorder rate i the sample beig studied, ad accordig to the relative importace for that study of false positives ad false egatives. It may also be appropriate to adjust cutoffs for age ad geder. Ogoig cliical ad epidemiological studies usig the SQ should provide the basis for cut-offs adjusted for these sample characteristics. I additio, plaed trials should establish if the predictive validity of the SQ ca further be improved by a algorithm that combies SQ scores with scores from a additioal ad eve briefer screeig istrumet that elicits the respodet's view o whether the child has sigificat emotioal or behavioural difficulties, ad o the extet to which these difficulties result i social impairmet or distress for the child, or burde for others. Util these various studies are completed, SQ users ca use the provisioal cut-off scores show i Appedix B, which are derived partly from the samples used for this study ad partly from other ogoig epidemiological surveys usig the SQ. The "borderlie" cut-offs ca be used for studies of high-risk samples where false positives are ot a major cocer; the " abormal" cut-offs ca be used for studies of low-risk samples where it is more importat to reduce the rate of false positives. Coclusio These iitial fidigs suggest that the SQ may fuctio as well as the Rutter questioaires (ad, by iferece, the Achebach questioaires) while offerig 585 the followig additioal advatages: a compact format; a focus o stregths as well as difficulties; better coverage of iattetio, peer relatioships, ad prosocial behaviour; ad a sigle form suitable for both parets ad teachers, perhaps thereby icreasig paret-teacher correlatios. Ackowledgemets I am very grateful for the willig cooperatio of parets ad teachers, ad for the ivaluable assistace of E)r. Hilary Richards ad the staff of the three Lodo cliics that participated i the study: the epartmet of Paediatric etistry of Kig's etal Istitute, Camberwell Child Guidace Cetre, ad the epartmet of Child ad Adolescet Psychiatry, Houslow. Refereces Achebach, T. M. (1991a). Maual for the Child Behavior Checklist ad 1991 Profile. Burligto, VT: Uiversity of Vermot epartmet of Psychiatry. Achebach, T. M. (1991b). Maual for the Youth Self-Report ad 1991 Profile. Burligto, v f : Uiversity of Vermot epartmet of Psychiatry. Berg, I., Lucas, C, & McGuire, R. (1992). Measuremet of behaviour difficulties i childre usig stadard scales admiistered to mothers by computer: Reliability ad validity. Europea Child ad Adolescet Psychiatry, 1, Elader, J., & Rutter, M. (1996). Use ad developmet ofthe Rutter Parets' ad Teachers' Scales. Iteratioal Joural of Methods i Psychiatric Research, 6, Fomboe, E. (1989). The Child Behavior Checklist ad the Rutter Paretal Questioaire: A compariso betwee two screeig istrumets. Psychological Medicie, 19, 111-1S5. Goodma, R. (1994). A modified versio ofthe Rutter paret questioaire icludig items o childre's stregths: A research ote. Joural of Child Psychology ad Psychiatry, 35, Haley, J. A., & McNeil, B. J. (1982). The meaig ad use of the area uder a receiver operatig characteristic (ROC) curve. Radiology, 143, Haley, J. A., & McNeil, B. J. (1983). A method of comparig the areas uder receiver operatig characteristic curves derived from the same cases. Radiology, 148, Rutter, M. (1967). A childre's behaviour questioaire for completio by teachers: Prelimiary fidigs. Joural oj Child Psychology ad Psvehiatry, 8, Rutter, M., Tizard. J., & Whitmore, K. (1970). Educatio, health ad behaviour. Lodo: Logma. Schachar, R., Rutter, M., & Smith, A. (1981). The characteristics of situatioally ad pervasively hyperactive childre: Implicatios for sydrome defiitio. Joural of Child Psychology ad Psychiatry, 22, Accepted mauscript received 26 September 1996

6 586 R. GOOMAN Appedix A: Stregths ad ifficulties Questioaire For each item, please mark the box for Not True, Somewhat True or Certaily True. It would help us if you aswered all items as best you ea eve if you are ot absolutely certai or the item seems daftl Please give your aswers o the basis of the child's behaviour over the last six moths or this school year. Childs Name Male/Female ate of Birth. Cosiderate of other people's feeligs Restless, overactive. caot stay still for log Ofte complais of headaches, stomach-aches or sickess Shares readily with other childre (treats, toys, pecils etc) Ofte has temper tatrums or hot tempers Rather solitary, teds to play aloe Geerally obediet, usually does what adults request May worries, ofte seems worried Helpful if someoe is hurt, upset or feelig ill Costatly fidgetig or squirmig Has at least oe good fried Ofte fights with other childre or bullies them Ofte uhappy, dow-hearted or tearful Geerally liked by other childre Easily distracted, cocetratio waders Nervous or cligy i ew situatios, easily loses cofidece Kid to youger childre Ofte lies or cheats Picked o or bullied by other childre Ofte voluteers to help others (parets, teachers, other childre) Thiks thigs out before actig Steals from home, school or elsewhere Gets o better with adults tha with other childre May fears, easily scared Sees tasks through to the ed. good attetio spa Not True Somewhat True Certaily True Sigature ate Paret/Teacher/Other (please specify:) Thak you very much for your help Robert Goodma, 1977 Appedix B: Provisioal Badig of SQ Scores These bads, which are ot adjusted for age or geder, have bee chose so that roughly 80% of childre i the commuity are ormal, 10 % are borderlie, ad 10 % are abormal. Paret completed Total ifficulties Score Emotioal Symptoms Score Coduct Problems Score Hyperactivity Score Peer Problems Score Prosocial Behaviour Score Teacher completed Total ifficulties Score Emotioal Symptoms Score Coduct Problems Score Hyperactivity Score Peer Problems Score Prosocial Behaviour Score Normal Borderlie Abormal ^ ^ l^-* ^

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