ADAPTATI ON TO PORTUGUESE OF THE DEPRESSI ON, ANXI ETY AND STRESS SCALES ( DASS)
João Luís Alv es Apóst olo1 Aida Cr uz Mendes2 Z aida Agu iar Azer edo3
Apóst olo JLA, Mendes AC, Azer edo ZA. Adapt at ion t o Por t uguese of t he Depr ession, Anx iet y and St r ess Scales ( DASS) . Rev Lat in o- am En f er m agem 2 0 0 6 n ov em br o- dezem br o; 1 4 ( 6 ) : 8 6 3 - 7 1 .
Obj ect iv e: t o adapt t o Por t uguese, of Por t ugal, t he Depr ession, Anx iet y and St r ess Scales, a 21- it em sh or t scale ( DASS 2 1 ) , design ed t o m easu r e depr ession , an x iet y an d st r ess. Met h od: Af t er t r an slat ion an d back - t r an slat ion w it h t h e h elp of ex per t s, t h e DASS 2 1 w as adm in ist er ed t o pat ien t s in ex t er n al psy ch iat r y consult s ( N= 101) , and it s int er nal consist ency, const r uct validit y and concur r ent validit y w er e m easur ed. Result s: The DASS 21 pr oper t ies cer t ify it s qualit y t o m easur e em ot ional st at es. The inst r um ent r ev eals good int er nal consist ency . Fact or ial analy sis show s t hat t he t w o- fact or st r uct ur e is m or e adequat e. The fir st fact or gr oups m ost of t he it em s t hat t heor et ically assess anx iet y and st r ess, and t he second gr oups m ost of t he it em s t hat assess depr ession, explaining, on t he w hole, 58.54% of t ot al var iance. The st r ong posit ive cor r elat ion bet w een t h e DASS 2 1 an d t h e Hosp it al An x iet y an d Dep r ession scale ( HAD) con f ir m s t h e h y p ot h esis r eg ar d in g t h e cr it er ion v alidit y , how ev er , r ev ealing fr agilit ies as t o t he div er gence bet w een t heor et ically differ ent const r uct s.
DESCRI PTORS: depr ession ; an x iet y ; st r ess; scales; ev alu at ion
ADAPTACI ÓN PARA LA LENGUA PORTUGUESA DE
LA DEPRESSI ON , AN XI ETY AN D STRESS SCALE ( DASS)
Obj et ivo: adapt ar a la lengua por t uguesa, de Por t ugal, la Depr ession, Anxiet y and St r ess Scale, ver sión cor t a de 21 ít em s, ( DASS- 21) , que per m it e ev aluar depr esión, ansiedad y est r és. Mét odo: Después de haber sido t r aducida y r et r ov er t ida, con la ay uda de per it os, la DASS- 2 1 fue adm inist r ada a enfer m os en consult a ex t er na de psiquiat r ía ( N= 1 0 1 ) , y fue ev aluada la consist encia int er na, la v alidez de const r uct o y la v alidez concur r ent e. Result ados: Las pr opiedades de la DASS- 21 at est iguan su calidad par a evaluar est ados em ocionales. El inst r um ent o r eveló buena consist encia int er na. El análisis fact or ial m uest r a que la est r uct ur a de dos fact or es es la m ás aj u st ada. El pr im er f act or agr u pa la m ay or ía de los ít em s qu e t eór icam en t e ev alú an an siedad y est r és, y el segu n do agr u pa la m ay or ía de los ít em s qu e ev alú an depr esión , ex plican do en su con j u n t o el 58,54% de la v ar iación t ot al. La fuer t e cor r elación posit iv a ent r e la DASS- 21 y la escala Hospit al Anx iet y and Depr ession con f ir m a la h ipót esis r elat iv a a la v alidez de cr it er io, sien do sin em bar go r ev eladas f r agilidades r elat iv am en t e a la div er gen cia en t r e con st r u ct os t eór icam en t e difer en t es.
DESCRI PTORES: depr esión ; an siedad; est r és; escalas; ev alu ación
ADAPTAÇÃO PARA A LÍ NGUA PORTUGUESA
DA DEPRESSI ON, ANXI ETY AND STRESS SCALE ( DASS)
Ob j et iv o: ad ap t ar p ar a a lín g u a Por t u g u esa, d e Por t u g al, a Dep r ession , An x iet y an d St r ess Scale, v er são cur t a de 21 it ens ( DASS- 21) , que per m it e av aliar depr essão, ansiedade e est r esse. Mét odo: Após t er sid o t r ad u zid a e r et r ov er t id a, com a aj u d a d e p er it os, a DASS- 2 1 f oi ad m in ist r ad a a d oen t es em con su lt a ex t er n a de psiqu iat r ia ( N= 1 0 1 ) , e f oi av aliada a con sist ên cia in t er n a, a v alidade de con st r u t o e a v alidade concor r ent e. Result ados: As pr opr iedades da DASS- 21 at est am a sua qualidade par a avaliar est ados em ocionais. O in st r u m en t o r ev elou boa con sist ên cia in t er n a. A an álise f at or ial m ost r a qu e a est r u t u r a de dois fat or es é m ais aj ust ada. O pr im eir o fat or agr upa a m aior ia dos it ens que t eor icam ent e av aliam ansiedade e est r esse e o segundo agr upa a m aior ia dos it ens que avaliam depr essão, explicando no seu conj unt o 58,54% da var iância t ot al. A for t e cor r elação posit iv a ent r e a DASS- 21 e a HAD confir m a a hipót ese r elat iv a à v alidade de cr it ér io, sendo no ent ant o r ev eladas fr agilidades r elat iv am ent e à div er gência ent r e const r ut os t eor icam ent e difer ent es.
DESCRI TORES: depr essão; an siedade; est r esse; escalas; av aliação
1
RN, PhD in Nur sing Science; Resear cher, Healt h Science Resear ch Unit , e- m ail: j oaoapost [email protected] ; 2 RN, PhD; Coor dinat ing Pr ofessor, Resear cher, Healt h Science Resear ch Unit , e- m ail: am [email protected] . Higher School of Nur sing Dr. Ângelo da Fonseca, Coim bra, Por t ugal; 3 PhD, MD, Abel Salazar
I nst it ut e of Biom edical Sciences, Por t o Univer sit y, Por t ugal, e- m ail: zaida@net c.pt
I NTRODUCTI ON
T
h e r el a t i o n b et w een n eg a t i v e em o t i o n a l st at es has been t he obj ect of clinical, concept ual and o p er at i o n al at t en t i o n , co n si d er i n g t h at r esear ch es hav e dev eloped m odels t o ex plain t he differ ent iat ion an d su per posit ion bet w een an x iet y an d depr ession , as w ell as inst r um ent s t o assess t hese m ood st at es, su ch as t h e sh or t v er sion of t h e DASS- 4 2 , i. e. t h e DASS- 2 1( 1 ).The adapt at ion of t his scale t o Por t uguese is j ust ified by t he fact t hat it s specific qualit ies allow for t he sim ult aneous assessm ent of t hree em ot ional st at es - d ep r ession , an x iet y an d st r ess - , b ecau se it is a s h o r t v e r s i o n , e a s i l y a p p l i c a b l e i n t h e c l i n i c a l en v ir on m en t , an d becau se it can be u sed t o assess t hese st at es in adolescent s and adult s.
Alt hough anx iet y and depr ession ar e usually consider ed as dist inct st at es, bot h disor der s pr esent su p er p o si n g ch ar act er i st i cs. As sh o w n b el o w , t h i s su p er p osit ion led t o t h e d ev elop m en t of m od els t o ex p l a i n co m m o n a n d d i st i n ct i v e ch a r a ct er i st i cs o f t hese t w o concept s.
I n f a ct , t h e d i scu ssi o n a b o u t t h e r el a t i o n bet w een anx iet y and depr ession has been t he t ar get of different st udies and is as old as research on t hese sy ndr om es, hav ing been int er pr et ed as: a) differ ent p o i n t s i n t h e s a m e c o n t i n u u m ; b ) a l t e r n a t i v e m an ifest at ion s of a diat h esis, an u n der ly in g disease w it h t h e sam e n at u r e; c) h et er ogen eou s sy n dr om es t hat ar e associat ed because t hey shar e som e subt ypes of sym pt om s; d) separ at e phenom ena in w hich, over t i m e , e a c h c a n d e v e l o p t h e o t h e r ; e ) d i s t i n c t p h e n o m e n a f r o m a c o n c e p t u a l a n d e m p i r i c a l v i ew p o i n t . St u d i es f o cu si n g o n a sh ar ed f act o r o f gener al dist r ess t en d t o see an x iet y and depr ession
as p oin t s in t h e sam e con t in u u m or as a com m on diat hesis ( a and b) , w hile research focusing on specific fact or s point t ow ar ds dist inct phenom ena ( d and e) . H o w e v e r, a f u l l c h a r a c t e r i z a t i o n o f a n x i e t y a n d d e p r e s s i o n s h o u l d c o n s i d e r e a c h o f t h e s e p er sp ect iv es( 2 ).
Th e t r ipar t it e anx iet y and depr ession m odel ex plain s su per posin g an d dist in ct iv e ch ar act er ist ics. Th i s m o d e l i n d i ca t e s t h e f o l l o w i n g t h r e e f a ct o r s: Negat iv e Af f ect ion ( NA) , gr ou pin g ch ar act er ist ics of anx iet y and depr ession; r educed Posit iv e Affect ( PA) , c o m m o n i n d e p r e s s i o n , a n d Ph y s i o l o g i c a l Hy per st im ulat ion ( FH) , com m on in anx iet y( 2).
Th e s t r e s s c o n c e p t p u t s u p a d d i t i o n a l qu est ion s r elat ed t o t h e st u dy of n egat iv e af f ect iv e st at es or condit ions, and is considered as an affect ive react ion st andard or st at e t hat has clear affinit ies w it h an x iet y( 1 ).
Am ong ex ist ing scales t o assess m ood st at e a l t e r a t i o n s, t h e D ASS- 2 1 h a s b e e n t r a n sl a t e d t o differ ent languages and used in a num ber of validat ion st u d ies.
Va r i o u s st u d i es h av e b een p u b l i sh ed t h a t apply t he DASS- 21 t o clinical sam ples, t w o of w hich developed w it h an English ver sion( 3- 4) and one w it h a Spanish version( 5), using sam ples of 258, 439 and 98 su b j ect s, r esp ect iv ely.
Tw o s t u d i e s h a v e b e e n p u b l i s h e d i n Por t uguese( 6- 7) w hich apply t he DASS- 4 2 t o sam ples of 295 and 200 subj ect s, r espect iv ely.
The t hr ee DASS subscales can be consider ed consist ent w it h t he t r ipar t it e m odel( 2), as depr ession is char act er ized by low posit iv e affect , r educed self-est eem and encour agem ent , and despair ; anx iet y by physiological hyper st im ulat ion and st r ess by per sist ent t ension, ir r it abilit y and low t hr eshold t o becom e upset or fr u st r at ed.
I n t his cont ext , t his st udy aim s t o adapt t he D ep r essi o n , An x i et y a n d St r ess Sca l es ( D ASS) t o Por t u g u ese.
METHODOLOGY
An i n st r u m en t ’s v al i d i t y d em o n st r at es t h e ex t ent t o w hich an inst r um ent or em pir ical indicat or m easu r es w h at it is su p p osed t o m easu r e. For t h e c r o s s - c u l t u r a l a d a p t a t i o n o f t h e D A S S - 2 1 , a m et h od olog y w as ad op t ed t o t est it s m easu r em en t p r o p e r t i e s a n d e q u i v a l e n c e i n t h e n e w c u l t u r a l co n t ex t .
I n i t i a l l y, t h e D ASS- 2 1 w a s t r a n s l a t e d t o Por t uguese fr om Por t ugal by a m ent al and psychiat r ic h ealt h n u r sin g sp ecialist an d b y a b ilin g u al En g lish t eacher, result ing in version 1. Bot h versions, i.e. t he or ig in al an d 1 , w er e sen t b y e- m ail t o a b ilin g u al Por t uguese w ho lived in t he USA and pr oduced ver sion 2 of t he DASS- 21.
t he or iginal aut hor, w ho suggest ed changes in it em s 4 and 10. These suggest ions w er e accept ed, r esult ing in v er sion 3.
Consensual v alidat ion( 8) w as r ealized by four m ent al and psychiat ric healt h nursing specialist s fluent in English, w ho assessed and com par ed t he differ ent v e r s i o n s i n t e r m s o f s e m a n t i c , i d i o m a t i c a n d con cept u al equ iv alen t of t h e it em s’ con t en t s. Wh en no consensus could be r eached about t he suggest ions, t he highest num ber of agr eem ent s am ong t he j udges w as pr efer r ed. This r esult ed in t he definit iv e v er sion. A pr et est w as r ealized w it h a sam ple of fiv e per sons during psychiat ric consult s, w ho did not r eveal a n y d i f f i cu l t y t o u n d e r st a n d t h e co n t e n t s o f t h e st at em en t s.
Rel i ab i l i t y, cr i t er i o n an d co n st r u ct v al i d i t y w er e assessed( 9 - 1 0 ). Rel i a b i l i t y co r r esp o n d s t o t h e d e g r e e o f c o n g r u e n c e a t w h i c h t h e a t t r i b u t e i s m easu r ed . Th u s, in t er n al con sist en cy w as an aly zed t hr ough t he correlat ion bet w een t he it em and t he scale t ot al it t heor et ically belongs t o and Cr onbach’s alpha for each scale. Crit erion validit y w as assessed t hrough t h e cor r elat ion b et w een t h e DASS- 2 1 an d an ot h er eq u i v al en t m easu r e, t h at i s, co n co m i t an t v al i d i t y. Con st r u ct v alidit y w as assessed t h r ou gh ex plor at or y fact or analysis of principal com ponent s w it h ort hogonal var im ax r ot at ion( 9- 10). To com plem ent fact or analy sis, w e an aly zed t h e cor r elat ion bet w een t h e it em s an d t he t ot al score for each subscale. This analysis serves as a good st ruct ural validit y argum ent , w hich indicat es t hat t he it em s m easur es t he const r uct of t he scale it belon gs t o an d n ot an ot h er. A good v alidit y f or t h e it em show s t hat t he it em ’s cor r elat ion w it h t he scale it belon gs t o is su bst an t ially h igh er t han cor r elat ion w it h t he scale it does not belong t o( 7).
I n st r u m en t s
Th e DASS- 2 1( 1 ) is a set of t h r ee f ou r - poin t Li k er t su b sca l es f o r sel f - r ep o r t i n g . Ea ch su b sca l e co n si st s o f se v e n i t e m s, a i m e d a t a sse ssi n g t h e em ot ional st at es of depr ession, anx iet y and st r ess.
Par t icipant s ar e ask ed t o m ar k t he ex t ent t o w hich each st at em ent applied t o him / her dur ing t he last w eek . Ther e ar e four possible answ er s in t er m s of sev er it y or fr equency, or ganized in a scale fr om 0 t o 3. The r esult is obt ained by adding up t he scor es of t he it em s for each of t he t hr ee subscales.
The depr ession subscale assesses sy m pt om s lik e in er t ia; an h edon ia; dy sph or ia; lack of in t er est /
involvem ent ; self- depr eciat ion; devaluat ion of life and
d i sco u r a g e m e n t . Th e a n x i e t y su b sca l e e v a l u a t e s
e x c i t a t i o n o f t h e a u t o n o m o u s n e r v o u s s y s t e m ;
m usculoskelet al effect s; sit uat ional anxiet y; subj ect ive
a n x i e t y e x p e r i e n ce s . Fi n a l l y, t h e st r e ss su b sca l e
assesses difficult y t o r elax ; ner v ous ex cit at ion; easy p e r t u r b a t i o n / a g i t a t i o n ; i r r i t a b i l i t y / e x a g g e r a t e d
r eact ion an d im pat ien ce.
Th e Hospit al An x iet y an d Depr ession ( HAD) Scale( 11), used in t his st udy as a concurrent validat ion cr it er ion , w as dev eloped t o obt ain an in st r u m en t t o m easur e t he sev er it y of anx iet y and depr ession in a non- psychiat ric environm ent . Validat ion st udies of t his in st r u m en t f or t h e Por t u g u ese lan g u ag e h av e b een published( 12- 13).
I t em s 1 , 7 an d 1 1 of t h e an x iet y su b scale assess t ension, unr est and agit at ion, w hile it em 5 looks at concer n. The r em aining t hr ee it em s ( 3, 9 and 13) seem t o lie closer t o t he aut onom ic anxiet y const r uct . This four - point self- r epor t Liker t scale consist s of 14 it em s, seven of w hich assess anxiet y and seven depr ession. Each st at em ent is answ er ed by under lining how t he per son has felt dur ing t he last w eek. Answ er s ar e r ank ed on a scale fr om 0 t o 3 and t he r esult of each dim ension is obt ained by adding up t he answ er s t o t he it em s in each subscale.
Sam ple and dat a collect ion
B e f o r e t h e s t a r t o f d a t a c o l l e c t i o n , t h e r e s e a r c h p r o j e c t w a s a p p r o v e d b y t h e Et h i c s Com m ission of a Psychiat ric Hospit al in t he Dist rict of Coim b r a, Por t u g al.
Th e DASS an d t h e HAD w er e ap p lied t o a sam ple of 101 per sons w ho at t ended ext er nal consult s at t hat Psychiat ric Hospit al bet w een April 2nd and June 22nd 2004.
Pe o p l e w h o a cce p t e d t o p a r t i ci p a t e w e r e ask ed t o sign t h e f r ee an d in f or m ed con sen t t er m . The necessar y condit ions w er e offer ed t o allow each par t icipant t o answ er, w it h t he necessar y help of t he r esear cher or a nur se r esponsible for t he ser v ice, in or der t o clar ify any doubt s.
RESULTS
St u dy sam ple ch ar act er ist ics
Th u s, t h e st u d y w as car r i ed o u t w i t h 1 0 1 y ou n g , ad u lt an d eld er ly p er son s, w it h a m in im u m ag e of 1 7 an d m ax im u m of 8 0 y ear s ( m ean 4 5 . 4 1 y ea r s a n d st a n d a r d d ev i a t i o n 1 2 . 5 7 y ea r s) . Mo st par t icipant s ( 63.37% ) w er e w om en. I n t er m s of civ il st at us, 69.31% w er e m ar r ied, 21.78% single, 6.93% d i v o r c e d a n d 1 . 9 8 % w i d o w e d . W i t h r e s p e c t t o educat ion, 52. 48% had four y ear s, 18. 81% bet w een 5 and 9 year s, 16.83% bet w een 10 and 12 year s and 1 1 . 8 8 % higher educat ion.
Reliabilit y st u dy
As ex p ect ed , t h e DASS- 2 1 r ev ealed st r on g int er nal consist ency, w it hout pr oblem it em s and w it h cor r ect ed v alu es f or cor r elat ion b et w een each it em and t he scor e of t he subscale it t heor et ically belongs t o r anging bet w een 0.31 and 0.78 and bet w een each it em and t he scor e of t he 21 it em s bet w een 0.42 and 0.83. Cr onbach’s alpha w as 0.90 for depr ession, 0.86 for anx iet y, 0. 88 for st r ess and 0. 95 for t he t ot al of t he t hr ee subscales.
Con st r u ct v alidat ion
Fact or analy sis of pr incipal com ponent s w it h Var i m ax r o t at i o n( 9 - 1 0 ) d i d n o t cl ear l y ev i d en ce t h e t h r ee- f act o r so l u t i o n , as p r o p o sed b y t h e o r i g i n al a u t h o r. Al t h o u g h , u si n g t h e cr i t e r i o n o f r e t a i n i n g f act or s w h ose ow n v alu es w er e h igh er t h an 1 , an d alt h ou gh t h e it em s dist r ibu t ed t h e r espect iv e f act or loads across t hree fact ors, w e did not find a concept ual ident it y t hat corresponded t o t he original classificat ion in an y of t h ese f act or s. As t o t h e st r ess su b scale, it em s 8, 11, 12, 14 and 18 sat ur at e bet w een 0.59 and 0.80 in fact or 1, but it em 6 sat ur at es in fact or 2 ( 0.50) and it em 1 sat ur at es in fact or 3 ( 0,69) . I t em s 7, 15, 19 and 20 of t he anx iet y subscale sat ur at e bet w een 0 . 5 7 an d 0 . 7 3 in f act or 1 , bu t t h e r em ain in g t h r ee it em s dist ribut e t he respect ive fact or loads across t he ot her t w o fact or s. Finally, in t he depr ession subscale, fiv e it em s display t heir highest fact or load, bet w een 0.48 and 0.73, in fact or 2. How ever, it em 5 sat ur at es in fact or 3 ( 0.60) and it em 13 in fact or 1 ( 0.66) .
Giv en t hat t hese r esult s dem onst r at e a t hr ee-dim en sion al st r u ct u r e an d con sider in g t h e fact t h at ,
in fact or analy sis, nine it em s of t he anx iet y and st r ess subscales sat urat e in t he sam e fact or, w e select ed a f o r c e d o r t h o g o n a l s o l u t i o n f o r t w o f a c t o r s , s u p p r e s s i n g t h e f a c t o r l o a d s u n d e r 0 . 3 0 , w h i c h ex plain 29. 51 and 29. 04% , r espect iv ely, t hat is, 58. 55 % of t ot al var iance, as obser ved in Table 1 .
Ta b l e 1 - Ma i n co m p o n en t m a t r i x * a f t er Va r i m a x r o t a t i o n , f o r ce d f o r t w o f a ct o r s ( F1 a n d F2 ) a n d ( cor r ect ed ) Cor r elat ion m at r ix * * of DASS- 2 1 it em s w it h t ot al d im en sion s, con sid er in g t w o d im en sion s, an x iet y / st r ess an d d ep r ession . ( n = 1 0 1 )
s m e t
I F1 F2 Anxiety
s s e r t
S Depression
e v a h o t e g a n a m t o n d i D : 3 D g n il e e f e v i t i s o p y n
a (0.712) 0.614 0.732
o t e m r o f t l u c i f f i d s a w t I : 5 D s g n i h t o d o t e v i t a i t i n i e k a
t (0.441)(0.442) 0.584 0.666
s a w e r e h t t a h t t l e f I : 0 1 D e m e k a m d l u o c t a h t g n i h t o n e v i t i s o p e v a h ( d a e h a e v o m ) s n o i t a t c e p x e ) 0 2 3 . 0
( (0.800) 0.708 0.852
d e s s e r p e d d n a d a s t l e f I : 3 1
D (0.588)(0.506) 0.727 0.752
l e e f o t e g a n a m t o n d i d I . 6 1 D g n i h t y n a t u o b a c i t s a i s u h t n
e (0.780) 0.653 0.807
y r e v h t r o w t o n s a w I t l e f I : 7 1 D n o s r e p a s a h c u
m (0.355)(0.729) 0.668 0.853
o n d a h e f il y m t l e f I : 1 2 D r e v e o s t a h w g n i n a e
m (0.361)(0.743) 0.701 0.832
h t u o m y m t a h t d e z il a e r I : 2 A y r d s a
w (0.495)(0.316) 0.538 0.499
e h t a e r b o t y t l u c i f f i d t l e f I : 4 A r o g n i h t a e r b t s a f y r e v : . g . e ( f o e c n e s b a e h t n i r i a f o k c a l ) t r o f f e l a c i s y h p ) 1 5 4 . 0
( (0.467) 0.608 0.574
s d n a h y m n i ( s r o m e r t t l e f I : 7 A ) e l p m a x e r o f s g e l r
o (0.792)(0.304) 0.762 0.642
t u o b a d e n r e c n o c s a w I : 9 A d l u o c I h c i h w n i s n o i t a u t i s s u o l u c i d i r a y a l p d n a c i n a p e l o r ) 3 3 7 . 0
( 0.634 0.692
d e k c i n a p t s o m l a I : 5 1
A (0.660)(0.452) 0.746 0.700
y m f o g n i t a e b e h t t l e f I : 9 1 A t o n s a w I n e h w n e v e t r a e h t r o f f e l a c i s y h p y n a g n i k a m r o t a e b t r a e h d e t a r e l e c c a : . g . e ( ) e r u l i a f t a e b t r a e h ) 1 3 8 . 0
( 0.656 0.473
y n a t u o h t i w d i a r f a s a w I : 0 2 A n o s a e r d o o
g (0.545)(0.469) 0.682 0.612
m l a c o t s e i t l u c i f f i d t l e f I : 1 S e r u s s e r p e s a e l e r / n w o
d (0.431) 0.412 0.394
e v a h o t d e d n e t I : 6 S n i s n o i t c a e r d e t a r e g g a x e s n o i t a u t i s n i a t r e c ) 8 6 3 . 0
( (0.574) 0.602 0.605
s u o v r e n y r e v t l e f I : 8
S (0.609)(0.560) 0.775 0.748
d e t a t i g a s a w I t l e f I : 1 1
S (0.692)(0.439) 0.776 0.678
x a l e r o t s e i t l u c i f f i d t l e f I : 2 1
S (0.742)(0.427) 0.799 0.707
n e h w t n a r e l o t n i s a w I : 4 1 S m o r f e m d e p p o t s g n i h t y n a g n i o d s a w I t a h w g n i o d ) 0 2 6 . 0
( (0.313) 0.644 0.526
e l b a t i r r i y r e v s a w I t l e f I : 8 1
S (0.695)(0.522) 0.831 0.753
d e n i a l p x e e v i t a l u m u C % e c n a i r a
v 29.50758.543
* Kaiser - Meyer - Olkin: 0.923; Bar t let t ’s spher icit y t est - Appr oxim at e Chi-squar e: 1493.426; p: 0.000.
The fir st fact or gr oups it em s belonging t o t he anxiet y and st ress dim ensions of t he original version. I t em 6 fr om t he st r ess subscale and it em 9 fr om t he anx iet y subscale, w hich assess ex agger at ed r eact ion an d sit u at ion al an x iet y , r espect iv ely, w er e ex clu ded fr om t his gr oup, because t heir m ain w eight s w er e 0.57 an d 0 . 7 3 in t h e secon d fact or. Ot h er pr oblem it em s ar e 4 an d 2 0 in t h e an x iet y su bscale, w h ich assess aut onom ic ner v ous sy st em ex cit at ion and subj ect iv e
anxiet y exper iences, as w ell as it em s 8 and 18 in t he
st r ess subscale, w hich assess ner v ous ex cit at ion and ir r it abilit y . Alt hough t hese it em s’ m ain fact or w eight
lies in fact or 1, w hich gr oups it em s t hat t heor et ically assess anx iet y and st r ess, t hey sat ur at e w it h v alues higher t han 0.30 in fact or 2, w it h w eight differ ences in each fact or low er t han 0.20. This r aises quest ions about t he discr im inat ion of t hese it em s in t he fact or assessin g t h ose con st r u ct s.
Th e secon d f act or j oin s it em s b elon g in g t o t h e d ep r essi o n scal e, w i t h f act o r w ei g h t s r an g i n g b e t w e e n 0 . 5 1 a n d 0 . 8 0 . Ho w e v e r, i t e m 5 , w h i ch assesses iner t ia, pr esent s ident ical fact or w eight s in t he t w o fact or s. Despit e sat ur at ing in t he fact or t hat g r o u p s d e p r e ssi o n i t e m s ( 0 . 5 1 ) , i t e m 1 3 , w h i ch assesses dy sph or ia, pr esen t s it s m ain f act or w eigh t ( 0. 59) in t he fact or t hat t heor et ically gr oups anx iet y and st r ess it em s. The r em aining it em s in t his gr oup p r esen t a d if f er en ce lar g er t h an 0 . 2 0 b et w een t h e w eight s of each fact or, w hich t est ifies in favor of t heir discr im inat ion in t he depr ession fact or.
Consider ing bot h gr oups, i.e. depr ession and anxiet y/ st r ess, t he cor r elat ion bet w een t he it em s and t he scor e of each w as calculat ed. As show n in Table 2 , ex cep t f o r i t em s 6 an d 9 , p r esen t i n g a si m i l ar correlat ion w it h t he t w o scores, t he correlat ion of t he r em aining 19 it em s is higher w it h t he scor es of each consider ed gr oup. This var ies bet w een 0.67 and 0.85 f o r d e p r e s s i o n , a n d b e t w e e n 0 . 4 1 a n d 0 . 8 3 f o r anx iet y / st r ess. How ev er, t hese differ ences, all low er t han 0. 20, do not ev idence t he discr im inat ion of t he it em s in t he fact or s pr oposed by t he or iginal aut hor.
Con cu r r en t v alid at ion
Th e Hospit al An x iet y an d Depr ession ( HAD) scale was used as a concurrent validat ion crit erion. I t r ev ealed g ood in t er n al con sist en cy w it h cor r elat ion bet ween t he it em and t he t ot al score of t he correct ed subscale, bet w een 0. 35 and 0. 66 for depr ession and bet w een 0.31 and 0.63 for anx iet y. Cr onbach’s alpha
corresponded t o 0.82 for depression, 0.80 for anxiet y and 0.89 for the total of the two subscales. Data in Table 2 show m oderate and strong correlation values between t he t wo concept s under analysis. Correlat ion is higher am ong total scores (0.74), but high values are also found am ong the various scores of the subscales, in relation to which a stronger correlation was found between the HAD anxiet y and t he DASS- 21 anxiet y and st ress t han wit h t h e D ASS- 2 1 d e p r e ssi o n . Fu r t h e r m o r e , t h e HAD depression is m ore st rongly correlat ed wit h t he DASS-21 depression than with the DASS-DASS-21 stress. These results ev idence a cer t ain degr ee of conv er gence/ div er gence bet ween t heoret ically equivalent / different concept s.
How ev er, t h e cor r elat ion b et w een t h e HAD d ep r ession an d t h e DASS- 2 1 d ep r ession is slig h t ly l o w er t h an b et w een t h e f o r m er an d t h e D ASS- 2 1 a n x i e t y, n o t e v i d e n ci n g t h e e x p e ct e d d i v e r g e n ce bet w een t heor et ically differ ent concept s. This fr agilit y deser v es f u r t h er discu ssion .
Th e in t er cor r elat ion s bet w een t h e DASS- 2 1 dim en sion s r ev eal h igh an d posit iv e v alu es, v ar y in g bet w een 0.80 and 0.85. These values ar e even higher, t h at is, equ al or su per ior t o 0 . 9 4 , am on g t h e t h r ee DASS- 2 1 su bscales an d t h e t ot al scor e of t h e t h r ee subscales’ 21 it em s. The cor r elat ion bet w een anx iet y a n d s t r e s s i s h i g h e r t h a n b e t w e e n a n x i e t y a n d depr ession, but t his differ ence is har dly significant .
Table 2 - Cor r elat ion m at r ix bet w een scor es of each DASS- 2 1 and HAD subscale. ( n= 1 0 1 )
S S A D
s n o i s n e m i D
S S A D
n o i s s e r p e D
S S A D
y t e i x n A
S S A D
s s e r t S
S S A D
/ y t e i x n A
s s e r t S
-S S A D
l a t o T
r p r p r p r p r p
-D A H
n o i s s e r p e
D 0.6110.000.6250.000.5430.000.607 0.000.6320.00
-D A H
y t e i x n
A 0.6630.000.7160.000.7000.000.736 0.000.7360.00
l a t o T -D A H
1 9 6 .
0 0.000.7270.000.6730.000.728 0.00 0.7410.00
-S S A D
n o i s s e r p e
D - - 0.8070.000.8220.000.846 0.000.9360.00
-S S A D
y t e i x n
A - - - - 0.8530.000.964 0.00 0.9410.00
-S S A D
s s e r t
S - - - 0.9610.000.9450.00
Descr ipt iv e scale v alu es
0 an d m ax im u m 2 1 ; m ean 1 1 . 0 6 ; 9 . 0 2 an d 1 1 . 8 4 a n d s t a n d a r d d e v i a t i o n 6 . 1 2 ; 5 . 6 5 a n d 5 . 4 6 , r espect ively. Alt hough t he m ean value for anx iet y is l o w e r t h a n f o r d e p r e ssi o n a n d st r e ss, t h e t h r e e c o n s t r u c t s u n d e r a n a l y s i s d i d n o t d i s p l a y a n y su b st an t ial d if f er en ces in t er m s of m ean v alu es or d isp er sion .
DI SCUSSI ON
I n or der t o assess t h e qu alit y of t h e DASS-2 1 , t h e r esu lt s of t h is st u d y w ill b e d iscu ssed an d com p ar ed w it h t h ose f r om ot h er scale v er sion s. I n t h i s st u d y, t h e v al u es f o u n d f o r Cr o n b ach ’s al p h a cer t ify t h e r eliabilit y of t h e scale an d ar e com par able w it h v alu es fou n d in ot h er st u dies u sin g t h e DASS-2 1( 3 - 5 ), w h i ch f o u n d : d e p r e ssi o n ( 0 . 9 4 ; 0 . 9 2 a n d 0 . 9 3 ) ; a n x i e t y ( 0 . 8 7 ; 0 . 8 1 a n d 0 . 8 6 ) a n d st r e ss ( 0 . 9 1 , 0 . 8 8 an d 0 . 9 1 ) an d al so w i t h r esu l t s f r o m st u d i e s t h a t u se d t h e Po r t u g u e se v e r si o n o f t h e DASS- 4 2( 6 - 7 ), w it h t h e f ollow in g Cr on b ach ’s alp h a, r esp ect i v el y : d ep r essi o n ( 0 . 9 6 an d 0 , 9 3 ) ; an x i et y ( 0 . 7 7 an d 0 . 8 3 ) an d st r ess ( 0 . 9 4 an d 0 . 8 8 ) . Th e r esu lt s f ou n d b y t h e or ig in al au t h or( 1 ) sh ou ld also be t ak en in t o accou n t , w h ich w er e, r espect iv ely f or depr ession , an x iet y an d st r ess: 0 . 9 1 , 0 . 8 4 an d 0 . 9 0 ; an d 0 . 8 1 , 0 . 8 3 an d 0 . 8 1 , t h e lat t er r ef er r in g t o t h e sev en it em s of each su b scale of t h e DASS- 4 2 t h at m ak e u p t h e DASS- 2 1 .
Fr om a st r u ct u r al v iew poin t , t h e t w o- f act or solut ion reveals bet t er dat a or ganizat ion, alt hough for on e of t h e sev en it em s in t h e d ep r ession su b scale an d f or t w o of t h e 1 4 it em s in t h e an x iet y / st r ess su b sca l e , t h e m a i n w e i g h t i s l o ca t e d o u t si d e t h e dim ension t hat gr oups t he r espect ive it em s. Mor eover, on e of t h e sev en it em s in t h e d ep r ession su b scale a n d f o u r i n t h e a n x i e t y / s t r e s s s u b s c a l e a r e pr oblem at ic, as t hey sat ur at e in bot h fact or s.
Th e se f i n d i n g s d i f f e r f r o m t h e r e su l t s o f st u d i e s u si n g t h e D ASS- 2 1 i n En g l i sh( 3 - 4 ) a n d i n Spanish( 5), w hich suppor t a t hr ee- fact or st r uct ur e.
S t u d i e s o f t h e D A S S - 4 2 i n En g l i s h( 1 4 - 1 5 ) in dicat ed som e discr epan cies in t h e it em s f r om t h e an x iet y an d st r ess su b scales, w h ich sim u lt an eou sly sat ur at ed in t he t w o fact or s. The sam e happened in a s t u d y t h a t u s e d a D u t c h v e r s i o n ( 1 6 ) , w i t h o u t discrim inat ion in relat ion t o t he t w o fact ors t he it em s belong t o.
D i scr ep a n ci es w er e a l so f o u n d i n t h e t w o st udies t hat used a Por t uguese v er sion of t he DASS-42. I n t he fir st( 6), t he aut hors init ially elim inat ed it em s 23, 30, 40 and 41, as t heir m ain fact or w eight s w er e l o ca t ed o u t si d e t h e d i m en si o n s t h ey t h eo r et i ca l l y belonged t o. Nev er t heless, in t he solut ion pr esent ed by t he aut hor s, it em s 7, 20, 28, 36 and 9 fr om t he anx iet y subscale sat ur at e out side t he fact or, t he fir st f ou r sat u r at in g in d ep r ession an d it em 9 in st r ess. Th e secon d st u dy( 7) in dicat ed t h at abou t h alf of t h e it em s in each of t he fact ors also sat urat ed in anot her fact or, m ainly in st r ess. Five it em s in t he depr ession subscale and four in t he anxiet y subscale exhibit ed a fact or load above 0.40 in t he st r ess fact or. I n t w o of t hese four, t he fact or w eight w as higher out side t he respect ive fact or. As t o t he st ress subscale, four it em s also sat u r at ed in t h e ot h er t w o fact or s, w it h v alu es ab ov e 0 . 4 0 , t w o of t h em in d ep r ession an d t w o in anxiet y. The w eight of one of t hem was higher in t he an x iet y f act or.
Fin ally, t h e st u d y b y t h e or ig in al au t h or( 1 ) r evealed t hr ee fact or s t hat explain 41.3% of var iance, clearly low er t han in t his st udy. All it em s sat urat ed in t he fact or t hey t heor et ically belonged t o, ex cept for it em 30, w hose fact or w eight w as higher in t he st r ess f act or t h an in an x iet y. Con f ir m at or y f act or an aly sis r esult s in t he sam e sam ple indicat ed t hat t he t hr ee-f act or m od el d em on st r at ed b et t er ad j u st m en t t h an t h e t w o f act or s. How ev er, in t h e t w o- f act or m od el, t h e an x iet y an d st r ess su bscales w er e or gan ized in one single fact or, w hich is com pat ible w it h our result s. Anxiet y is consider ed one of t he affect ive com ponent s of t h e st r ess pr ocess, t oget h er w it h ot h er em ot ion s l i k e a n g er a n d f ea r, w h i ch m ay a p p ea r w h en t h e individual does not m anage t o r espond t o t he st im uli he is subj ect t o( 17).
I n ou r st u d y, w e in t er cor r elat ed t h e DASS dim ensions, revealing high and posit ive values, w hich r ev eal a v er y st r ong associat ion bet w een t he scor es of t hese inst r um ent ’s subscales, r anging bet w een 0.81 an d 0 . 8 4 . Alt h ou gh t h e cor r elat ion bet w een an x iet y a n d s t r e s s i s h i g h e r t h a n b e t w e e n a n x i e t y a n d depr ession, t he differ ence is sm all.
I n com par ison w it h ot h er r esu lt s( 1 , 3 , 5 , 7 ), t h e f a c t o r i n t e r c o r r e l a t i o n s w e r e , r e s p e c t i v e l y : depr ession- anxiet y ( 0.54; 0.46; 0.71; 0.58) ; anxiet y-st r ess ( 0.65; 0.72; 0.73; 0.66) and depr ession- y-st r ess ( 0 . 5 6 ; 0 . 5 7 ; 0 . 7 9 ; 0 . 6 0 ) . A l t h o u g h i n g e n e r a l , co r r el at i o n l ev el s ar e h i g h er b et w een an x i et y an d st r ess t h a n b et w een a n x i et y a n d d ep r essi o n , t h e ext ent of t his difference is sm all. The st rengt h of t he relat ion present ed in a st udy w it h t he Spanish version( 5) appr ox im at ed t he r esult s found in our st udy.
Con cu r r en t v al i d i t y, assessed i n ou r st u d y t h r ou gh t h e r elat ion bet w een t h e DASS- 2 1 an d t h e H A D , a l s o d e s e r v e s f u r t h e r d i s c u s s i o n . Th e cor r elat ion s b et w een t h e d im en sion s an d t h e t ot al scor es of t he t w o subscales ar e highly posit iv e, w it h 0. 74 as t he highest v alue bet w een t he t ot als of t he t w o scales, as ex pect ed. High cor r elat ions w er e also ex pect ed bet w een t h eor et ically equ iv alen t con cept s, a n d l o w e r v a l u e s b e t w e e n t h e o r e t i ca l l y d i f f e r e n t c o n c e p t s . H o w e v e r, t h i s a s s o c i a t i o n i s n o t f u l l y e v i d e n c e d , g i v e n t h e r e d u c e d e x t e n t o f s o m e differ ences. I n som e cases, higher cor r elat ion v alues w er e f ou n d am on g t h eor et ically dif f er en t con st r u ct s t h an am on g t h eor et ically sim ilar on e, lik e b et w een HAD d ep r essi o n an d D ASS- 2 1 an x i et y ( 0 . 6 3 ) an d bet w een t he for m er and DASS- 21 depr ession ( 0.61) , w hich m ay show t hat w e are facing differ ent point s in t he sam e cont inuum or com m on char act er ist ics of t he t w o sy m pt om s.
A st udy using t he Por t uguese v er sion of t he D ASS- 4 2 a n d t h e H AD( 6 ) f o u n d l o w c o r r e l a t i o n s bet w een t he DASS- 42 depr ession, anx iet y and st r ess and t he HAD depr ession ( 0. 21, 0. 13 and 0. 14) , and m od er at e b et w een t h e d im en sion s of t h e DASS- 4 2 and t he HAD anxiet y ( 0.50, 0.42 and 0.57) , in w hich t he low correlat ion bet w een t he t w o depression scales st ands out ( 0.21) . These r esult s do not speak in favor of t h e in st r u m en t ’s con cu r r en t v alid it y as, in som e c a s e s , h i g h e r c o r r e l a t i o n s w e r e f o u n d b e t w e e n t h e o r e t i c a l l y d i f f e r e n t c o n s t r u c t s t h a t b e t w e e n t h eor et ically sim ilar on es.
I n a st udy using t he Spanish v er sion( 5), t he anxiet y subscale of t he DASS- 21 pr esent ed a st r onger cor r elat ion w it h t he Beck Anxiet y I nvent or y ( BAI ) t han w it h t he Beck Depr ession I nv ent or y ( BDI ) , w hile t he o p p o si t e h a p p en ed w i t h t h e d ep r essi o n su b sca l e. D e sp i t e a h i g h e r co r r e l a t i o n a m o n g t h e o r e t i ca l l y equivalent const ruct s, correlat ion values are st ill quit e si g n i f i ca n t a m o n g t h e o r e t i ca l l y d i st i n ct co n ce p t s
( alw ay s higher t han 0. 62) , as illust r at ed by t he fact t hat t he st ress subscale present ed a higher correlat ion w it h t he BDI ( 0.74) t han w it h t he BAI ( 0.62) .
An o t h er co n cu r r en t v al i d i t y st u d y w i t h an English version of t he DASS- 21( 3),using t he BAI , BDI an d St at e-Tr ait An x iet y I n v en t or y-T ( STAI -T) f ou n d h i g h e r c o r r e l a t i o n s a m o n g t h e o r e t i c a l l y s i m i l a r co n cep t s t h an am o n g t h eo r et i cal l y d i f f er en t o n es. How ev er, t h e STAI -T pr esen t ed a h igh er cor r elat ion w it h d ep r ession t h an w it h an x iet y or st r ess. Th u s, au t h or s in dicat e t h at t h e STAI -T m ay con t ain it em s t hat assess depr ession t oget her w it h anx iet y.
S c a l e s ’ c o n c u r r e n t v a l i d i t y i s g e n e r a l l y e v a l u a t e d b y e x a m i n i n g t h e e x t e n t o f t h e s e in st r u m en t s’ cor r elat ion s w it h m easu r es assessin g t heor et ically equiv alent const r uct s. The discr im inat ion of t he it em s in t he fact ors t hey t heoret ically belong t o is also a sign t hat t hey assess different concept s. Like in ot her st udies using t he sam e scale, our result s did not evidence great dist ances am ong t he t hree concept s a n d ev en sh o w ed t h a t a n x i et y a n d st r ess ca n b e gr ouped in t he sam e const r uct and, also, t hat som e it em s d o n ot d iscr im in at e each con cep t , an d ev en sat urat e in t he fact or t hey do not belong t o t heoret ically. I n f a c t , o u r s t u d y d i d n o t p r o d u c e a n y em pir ical ev idence of anx iet y, depr ession and st r ess being dist inct phenom ena. Dat a suppor t t he convict ion t hat t he concept s under analysis can be differ ent point s in t he sam e cont inuum ; alt er nat iv e m anifest at ions of a diat hesis; or het er ogeneous sy ndr om es, w hich ar e a s s o c i a t e d b e c a u s e t h e y s h a r e s o m e s y m p t o m su b t y p es.
The t r ipar t it e m odel( 2) indicat es t hat anx ious and depressed persons share a basic st ruct ure, which is n egat iv e af f ect ion or gen er al dist r ess. Th ese ar e responsible for t he st rong associat ion bet ween anxiet y and depression m easures, based on which t he original aut hors( 1) creat ed t he st ress subscale, which can sust ain t hat t he lat t er assesses a general dist r ess fact or, as support ed by a set of em pirical st udies( 18- 19) .
Anot her explanat or y m odel t hat is at t he sam e t im e cognit iv e, m ot iv at ional and r elat ional, conceiv es st r ess as par t of a br oader t opic: t he st udy of hum an em ot ion s. I n f act , t h e st r ess con cep t h as b ecom e in cr easin gly com plex( 2 0 ).
w e believ e in. Anx iet y em er ges in a r elat ional t hem e in w hich t he indiv idual is confr ont ed w it h uncer t aint y and/ or w it h an ex ist ent ial t hr eat . Alt hough t he basic t h r eat t h at u n d er l i es an x i et y i s ex i st en t i al - an d , c o n s e q u e n t l y, s y m b o l i c a n d v a g u e - w e c a n e x p e r i e n ce a n x i e t y w h e n w e h a v e t o f a ce a ct u a l danger. Then, t his danger t urns int o t he m at erializat ion of exist ent ial t hr eat s. Depr ession, on t he ot her hand, is em ot ion al, b u t it is n ot a sp ecif ic em ot ion . An d , t o g e t h e r w i t h o t h e r e m o t i o n s, i t i s p r o v o k e d b y unfavorable living condit ions. Depression is frequent ly t heor ized as t he r esult of a big loss, w hich pr ov ok es a feelin g of despair, of n o lon ger feelin g t h at life is w or t h it . I n t his perspect ive, var ious em ot ions can be ex per ien ced in depr ession , depen din g on t h e ph ase of t h e m ou r n in g pr ocess a per son is goin g t h r ou gh and on w hat happened in t he pr oduct ion of t he loss. Th u s, d ep r ession is accom p an ied b y em ot ion s lik e anxiet y, anger, guilt and sham e. Anxiet y in depression occu r s b ecau se t h e loss t h r eat en s ou r id en t it y an d m ak es us insecur e about t he fut ur e.
I n t his analysis m odel, st ress is an em ot ional st at e pr oduced w hen an indiv idual assesses ( int er nal or ext er nal) r equir em ent s as causes of dam age, t hr eat o r c h a l l e n g e a n d a s n o t h a v i n g t h e n e c e s s a r y r esour ces t o face t hem . Thus, em ot ions ar e r eleased in t he pr im ar y ( r equir em ent assessm ent ) as w ell as in t he secondar y ev aluat ion ( coping assessm ent ) , in w hich t he t hr ee concept s - st r ess, em ot ion and coping - const it ut e a concept ual unit . I n t his cont ext , em ot ions are t he m ain organizing concept , as it includes st ress and coping.
CONCLUSI ON
I n t e r m s o f i n t e r n a l c o n s i s t e n c y, t h e correlat ion scores bet w een t he it em s and t he subscale t h ey t h eor et i cal l y b el on g t o an d Cr on b ach ’s al p h a v a l u es g u a r a n t ee t h e r el i a b i l i t y o f t h e sca l e. Th e cor r elat ion b et w een t h eor et ically sim ilar con st r u ct s t est ifies in favor of t he validit y of t he scale. How ever, su b st a n t i a l co r r el a t i o n s w er e a l so f o u n d b et w een t h eor et ically differ en t con st r u ct s.
Th e t h r ee- f act or st r u ct u r e p r op osed b y t h e o r i g i n a l a u t h o r i s n o t c l e a r l y r e v e a l e d , a s t h e o r g a n i za t i o n o f a n x i e t y a n d st r e ss i t e m s i s m o r e adj ust ed t o one single fact or. Fr om a st r uct ural point of view , t w o it em s in t he anxiet y/ st r ess subscales and t w o m or e in t h e d ep r ession scale p r esen t a h ig h er fact or load out side t heir fact or.
Despit e t hese result s, t he Port uguese version of t h e DASS- 2 1 r ev ealed p r op er t ies t h at cer t if y it s qu alit y t o assess em ot ion al st at es, accom pan ied by lim it at ions inherent in it s capacit y t o assess t he t hree c o n s t r u c t s , i . e . d e p r e s s i o n , a n x i e t y a n d s t r e s s , se p a r a t e l y. An y w ay, t h e l e g i t i m a cy o f t h e st r e ss s u b s c a l e a s a n i n d e p e n d e n t m e a s u r e i s m o r e discu ssible t h an t h at of t h e depr ession su bscale, as m ost depr ession it em s discr im inat e in t he fact or.
Fu t u r e st u dies sh ou ld look at t h e st r u ct u r al quest ion, w it h a view t o guar ant eeing if t he inst r um ent can assess t h e t h r ee f act o r s sep ar at el y. Ho w ev er, t h ese r esu lt s m ay n ot in v alid at e t h e u se of t h r ee-fact or scales as clinical issues m ay ent ail t he need t o con sider t h em separ at ely.
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