Feb ua y 2018 | Volume 9 | A icle 101
O iginal esea ch
published: 05 Feb ua y 2018
doi: 10.3389/ psy .2018.00010
F on ie s in Psychia y | www. on ie sin.o g
Edi ed by:
Ka a ina Howne ,
Ka olinska Ins i u e (KI), Sweden
Re iewed by:
Giuseppe Sa o i,
Uni e si à degli S udi di
Pado a, I aly
E ich Flamme ,
Z P Suedwue embe g, Ge many
*Co espondence:
Jacin o Cos a Aze edo
[email p o ec ed]
Special y sec ion:
This a icle was submi ed o
Fo ensic Psychia y,
a sec ion o he jou nal
F on ie s in Psychia y
Recei ed: 25Oc obe 2017
Accep ed: 15Janua y2018
Published: 05Feb ua y2018
Ci a ion:
Aze edoJC, Pais-Ribei oJL,
CoelhoR and Figuei edo-B agaM
(2018) Valida ion o he Po uguese
Ve sion o Impulsi e–P emedi a ed
Agg ession Scale in an Inma e
Popula ion.
F on . Psychia y 9:10.
doi: 10.3389/ psy .2018.00010
Valida ion o he Po uguese
Ve sion o impulsi e–P emedi a ed
agg ession scale in an inma e
Popula ion
Jacin o Cos a Aze edo1,2*, José Luís Pais-Ribei o3, Rui Coelho1
and Ma ga ida Figuei edo-B aga1,2
1 Depa men o Neu oscience and Men al Heal h, Facul y o Medicine, Uni e si y o Po o, Po o, Po ugal, 2 I3S – Ins i u o
de In es igação e Ino ação em Saúde, Po o, Po ugal, 3 Facul y o Psychology and Educa ional Sciences, Uni e si y o
Po o, Po o, Po ugal
Agg ession is one o he co e symp oms o an isocial pe sonali y diso de (ASPD) wi h
he apeu ic and p ognos ic ele ance. ASPD is highly p e alen among inma es, being
esponsible o ad e se e en s and ele a ed di ec and indi ec economic cos s o
he c iminal jus ice sys em. The Impulsi e/P emedi a ed Agg ession Scale (IPAS) is a
sel - epo ins umen ha cha ac e izes agg ession as ei he p edomina ely impulsi e
o p emedi a ed. This s udy aims o de e mine he alidi y and eliabili y o he IPAS in
a sample o Po uguese inma es. A o al o 240 inma es we e included in he s udy.
A p incipal componen ac o analysis was pe o med so as o ob ain he cons uc alid-
i y o he IPAS impulsi e agg ession (IA) and p emedi a ed agg ession (PM) subscales;
in e nal consis ency was de e mined by C onbach’s alpha coe icien ; con e gen and
di e gen alidi y o he subscales we e de e mined analyzing co ela ions wi h he Ba a
Impulsi eness scale, 11 h e sion (BIS-11), and he Psychopa hic Checklis Re ised
(PCL-R). The o a ed ma ix wi h wo ac o s accoun ed o 49.9% o o al a iance.
IA subscale had 11 i ems and PM subscale had 10 i ems. The IA and PM subscales
had a good C onbach’s alpha alues o 0.89 and 0.88, espec i ely. The IA subscale is
co ela ed wi h BIS-11 a en ional, mo o , and non-planning impulsi eness dimensions
(p<0.05). The PM subscale is co ela ed wi h BIS-11 a en ional, mo o impulsi eness
dimensions (p<0.05). The PM subscale is co ela ed wi h PCL-R in e pe sonal, li es yle,
and an isocial dimensions (p<0.05). The IA subscale is no co ela ed wi h PCL-R. The
Po uguese ansla ed e sion o IPAS has adequa e psychome ic p ope ies, allowing
he measu emen o impulsi e and p emedi a ed dimensions o agg ession.
Keywo ds: agg ession, an isocial pe sonali y diso de , psychopa hy, impulsi i y, impulsi e–p emedi a ed
agg ession scale, Ba a impulsi eness scale, 11 h e sion, Psychopa hic checklis e ised
inT ODUcTiOn
Agg ession ep esen s a public heal h issue. Ha ing a nega i e impac on indi iduals and socie y
(1), i can be de ined as a “beha io al display in which physical o ce is used wi h he in en o ha m
o damage ano he indi idual o objec ” (2).
2
Aze edo e al. IPAS Validi y in Po uguese Inma es
F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
A clinical de ini ion o agg essi e beha io should conside
biological, en i onmen al, cul u al, and social a iables, and
hei in e play o ac as p edisposi ion o elici ing ac o s (3).
The ange o beha io s ha can be classi ied as agg essi e can
a y om e bal agg ession o homicide, and i is impo an o
cha ac e ize he le el o planning, he possible unde s anding o
hypo he ical consequences, he p esence o us a ions, insul s,
in e pe sonal a ack, h ea s, en i onmen al s esso s, and associ-
a ed psychopa hologies.
Empi ical li e a u e has p oposed a dicho omous agg ession
classi ica ion, i.e., impulsi e agg ession (IA; eac i e, a ec i e,
o non-planned), and p emedi a ed agg ession (PM; p oac i e,
ins umen al, p eda o y, o con olled) (4). The exp ession
“IA” e e s o uncon olled agg essi e ou bu s s ha a e ou
o p opo ion o he p o oking e en , while “PM” desc ibes
agg essi e beha io s ha a e planned, con olled, and/o goal-
o ien ed (5).
Acco ding o he agg ession ype, indi iduals may di e
in social adjus men , c iminal beha io , emo ional unc ion,
cogni i e pe o mance, au onomic esponse, and ea men
ou come (6, 7).
The IA ends o occu in he p esence o igge ing s imulus
ha is in e p e ed as h ea o p o oca ion (8). This ype o
agg ession in ol es a ec i e a ousal, leading o a apid and
uncon olled beha io al esponse. I has been co ela ed wi h
in o ma ion-p ocessing/neu ocogni i e impai men s, abusi e
home backg ounds, an ang y/impulsi e/anxious pe sonali y, and
high psychological s ess eac i i y (9).
The PM, by con as , ends o be a planned beha io ha has
a speci ic expec ed goal (8), and i can be explained as a lea ned
beha io (10). I has been co ela ed wi h poo pa en al con ol,
lack o a ec , psychopa hic pe sonali y, and low physiological
a ousal (9).
The classi ica ion o an agg essi e ac o a pa e n o agg es-
si e beha io allows ea men selec ion and iolence isk
managemen . The IA has a good esponse o pha macologic
ea men when mood s abilize s and/o an ipsycho ics a e
p esc ibed (11). In he case o PM, on he con a y, he esponse
o pha macological ea men is gene ally insu icien (12),
and o ensic/beha io al s a egies a e ecommended (7).
Fu he mo e, indi iduals wi h PM ha e a highe isk o iolen
c iminal ecidi ism han hose wi h IA (13).
The e is a link be ween agg essi e beha io and psychia ic
diso de s (14).
Indi iduals wi h dep ession, anxie y, psychosis, subs ance use
diso de s, hype ac i e a en ion de ici diso de , and pe sonali y
diso de s p esen a highe equency o agg essi e ac s (15).
Impulsi e agg ession has been linked o psychia ic diseases,
such as anxie y, dep ession, pe sonali y diso de s, and subs ance
use diso de s (16). PM has been associa ed wi h psychopa hic
pe sonali y ai s (17).
In pa icula , an isocial pe sonali y diso de (ASPD) is cha -
ac e ized by signi ican i i abili y, agi a ion, impulsi eness, and
hos ili y, and agg ession ep esen s one o i s co e symp oms (18).
ASPD is highly p e alen among inma es. I is, hus, esponsible
o ad e se e en s and ele a ed di ec and indi ec economic
cos s in he c iminal jus ice sys em (19).
An isocial pe sonali y diso de is he only acknowledged
psychia ic diso de ha con e s an inc eased isk o bo h IA
and PM (20–22), wi h se e al s udies epo ing psychopa hy and
psychopa hic ai s as isk ac o s o PM (23).
Psychopa hic Checklis Re ised (PCL-R) is he gold s and-
a d o psychopa hy assessmen and diagnosis, and sepa a es
psychopa hic ai s in o ou dimensions: (1) in e pe sonal,
(2) a ec i e, (3) li es yle, and (4) an isocial (24).
Impulsi i y has been ela ed o agg ession and is a symp om o
ASPD (25). Impulsi i y can be a necessa y ac o o agg ession
de elopmen (26). I can be de ined “as a p edisposi ion owa d
apid, unplanned eac ions o in e nal o ex e nal s imuli wi hou
ega d o he nega i e consequences o hese eac ions o he
impulsi e indi iduals o o o he s” (27).
Impulsi i y can be measu ed wi h Ba a Impulsi eness Scale,
11 h e sion (BIS-11), a sel - epo psychome ic ins umen
ha sepa a e impulsi i y in o h ee componen s: (1) ac ing on
he spu o he momen (mo o ac i a ion), (2) no ocusing on
he ask a hand (a en ion), and (3) no planning and hinking
ca e ully (lack o planning) (28). Indi iduals wi h sco es highe
han 72 a e conside ed highly impulsi e (29).
Pa ien s wi h subs ance use diso de s, dep ession, bipola
diso de , a en ion de ici /hype ac i i y diso de (AD/HD), as
well as suicide a emp e s and c iminal o ende s end o ha e
highe BIS-11 o al sco es (29).
Despi e he e idence suppo ing he no ion ha pe sons who
display an impulsi e agg essi e beha io a e dis inc om hei
coun e pa s who p esen a p emedi a ed beha io , he clini-
cal use ulness and gene aliza ion is ques ioned because mos
s udies included iolen inca ce a ed o ende s, o psychia ic
inpa ien s.
Wi hin he inca ce a ed popula ion, howe e , agg ession is a
ele an daily clinical conce n. The e o e, he s udy o agg es-
sion in o ensic psychia ic se ings should be encou aged in
o de o ind and p omo e he bes clinical p ac ices (30, 31).
I is impo an o use alida ed ins umen s in he e alua ion
o agg essi e ac s in p isone s in o de o imp o e medical in e -
en ions (32). In Po ugal, we do no ha e a alida ed agg ession
ca ego iza ion ins umen .
The e a e wo psychome ic ins umen s ha allow agg es-
sion ca ego iza ion: he impulsi e–p emedi a ed agg ession
scale (IPAS) and he eac i e–p oac i e agg ession ques ionnai e
(2, 33, 34).
In he o iginal alida ion s udy o IPAS, he sample comp ised
93 physically agg essi e men ec ui ed in he communi y wi h
a mean age o 35.9yea s, whose p incipal agg ession ype was
physical assaul (n=80). The agg ession was measu ed h ough
he Li e ime His o y o Agg ession, Buss Pe y Agg ession
Ques ionnai e, and he Agg ession In e iew. The p incipal
componen analysis iden i ied wo ac o s (IA and PM), which
accoun ed o 16.56 and 14.03% o o al a iance, espec i ely.
The in e nal consis ency measu ed by C onbach’s alpha was 0.77
o he IA ac o and 0.82 o he PM ac o . Sensi i i y o he IA
scale was 0.96 and speci ici y was 0.50. Fo he PM scale, sensi i -
i y and speci ici y we e 0.60 and 0.96, espec i ely (2).
All o he alida ion s udies o IPAS epo ed iden ical esul s
in p incipal componen analysis, wi h wo ac o s IA and PM.
TaBle 1 | Valida ion s udies o Impulsi e/P emedi a ed Agg ession Scale (IPAS).
e e ence sample Mean
agea
P incipal
agg ession
agg ession
measu es
in e nal
consis-
encyb
To al
ex plained
a iancec
nType O igin iadPMeia PM
S an o d e al. (2) 93 men Physically
agg essi e men
Communi y 35.9 86% physical
assaul
LHAQ , BPAQg,
AIh
0.77 0.82 16.56 14.03
Kockle e al. (35) 86 men P isone s Inpa ien
Fo ensic hospi al
38 83% con ic ed o
iolen c imesi, 37%
non-guil y by eason
o insani y
nsj0.81 0.72 20 13
Conne e al. (36) 61 women,
60 men
Pa ien s in ea men
o opia e dependence
Ou pa ien
Psychia ic Se ice
41.9 ns LHAQ, BPAQ 0.74 0.75 ns
Ma hias e al. (37) 24 gi ls,
42 boys
Adolescen s wi h
conduc diso de
Communi y 14.5 ns LHAQ, BPAQ 0.82 0.78 18.5 15.6
S an o d e al. (38) 113 men Men con ic ed o
domes ic iolence
Communi y 36 Domes ic
iolence
LHAQ 0.75 0.86 ns
Haden e al. (39) 213 women,
127 men
S uden s Communi y 19.06 ns BPAQ 0.77 0.81 24 12
Kuyck e al. (40) 149 men,
70 women
P isone s P ison 50%
be ween 25
and 39
75% con ic ed
o iolen c imes
ns 0.93 0.90 ns
Chen e al. (41) 389 women,
262 men
S uden s Communi y 26.1 ns BPAQ 0.70 0.66 12.9 11.9
Romans e al. (42) 114 women,
49 men
Psychia ic pa ien s Ou pa ien
Psychia ic Se ice
25.8 ns OASk0.85 0.76 23.3 10.1
aYea s.
bC onbach’s alpha.
c%.
dImpulsi e agg ession ac o .
eP emedi a ed Agg ession ac o .
Li e ime His o y o Agg ession.
gBuss Pe y Agg ession Ques ionnai e.
hAgg ession In e iew.
iAgg a a ed assaul , ba e y on a law o ice , sexual assaul , mu de , a med obbe y, a emp ed mu de , and manslaugh e .
jNo speci ied.
kO e Agg ession Scale.
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Aze edo e al. IPAS Validi y in Po uguese Inma es
F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
In e nal consis ency coe icien s a ied be ween 0.70 and 0.93 o
IA and be ween 0.66 and 0.90 o PM (Table1).
We in end o alida e he Po uguese e sion o he IPAS in
inma es and o de e mine i s psychome ic p ope ies. Thus,
we expec o eplica e he pu po ed wo- ac o model o IPAS;
we p edic ha he subscales o he IPAS and he BIS-11 will be
posi i ely co ela ed; we p edic ha he PM subscales o he
IPAS—unlike he IA ones—will be co ela ed wi h he PCL-R.
This s udy is a pa o a la ge s udy aiming o cha ac e ize
biological and psychosocial ac o s ha p edic he agg ession
ype in young adul male inma es.
MaTe ials anD MeThODs
Ou sample was collec ed a wo peni en ia y ins i u ions in
he No h o Po ugal. The esea ch p o ocol was o mally
app o ed by he E hics Commi ee o Cen o Hospi ala de
São João, Po o, Po ugal (Documen numbe 48.14), and by
he hos ing ins i u ion, he Gene al Di ec ion o P oba ion
and P ison Se ices. Pa icipa ion was olun a y and he e
was no ewa d o i . The pa icipan s we e all Po uguese.
W i en in o med consen was ob ained a e he p ocedu es
we e explained o he pa icipan s, in acco dance wi h he
Decla a ion o Helsinki.
Pa icipan s we e included i hey we e o e 18yea s old,
had a pe sonal his o y o agg ession in he pas 6mon hs, had
been e e ed o he clinical se ices o agg essions owa d
o he inma es, we e able o ead, and i hey we e capable o
p o iding hei w i en in o med consen . Socio-demog aphic
cha ac e is ics and o ensic his o y we e collec ed om
in e iews and clinical eco ds. We applied h ee psychome -
ic ins umen s: he IPAS, he BIS-11, and he PCL-R. This
sample does no in end o ep esen all he Po uguese inma e
popula ion, as he me hods in ol e a non-p obabilis ic sample
app oach.
T anscul u al adap a ion and Valida ion
In o de o add ess he anscul u al adap a ion and alida ion
o IPAS, an ini ial ansla ion was ca ied ou by a g oup o
Po uguese expe s. The back- ansla ion o his i s ansla ed
e sion was hen pe o med by a na i e English-speaking expe .
The i s g oup analyzed he seman ic and idioma ic co espond-
ence o he ansla ion and he back- ansla ion, and pe o med
a inal syn hesis ansla ion (43).
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Aze edo e al. IPAS Validi y in Po uguese Inma es
F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
Psychome ic ins umen s
Impulsi e–P emedi a ed Agg ession Scale
The IPAS is a 30-i em sel - epo ques ionnai e used o classi y
agg essi e ac s occu ing o e he p e ious 6mon hs. I ems a e
sco ed wi hin a i e-poin Like scale (1=S ongly Disag ee o
5=S ongly Ag ee). The scale di e en ia es wo ac o s: IA and
PM, wi h he weigh ed sco e allowing o he ca ego iza ion o
he ype o agg ession. The indi idual’s le el o IA and PM was
ob ained h ough he sum o 20 o he 30 i ems o he IPAS: he IA
i ems (eigh i ems: 3, 5, 7, 8, 9, 21, 24, and 26) and he PM i ems
(12 i ems: 1, 2, 6, 10, 11, 12, 14, 16, 17, 20, 29, and 30) (2).
Ba a Impulsi eness Scale-11
To de e mine he con e gen alidi y o he IA and he PA
subscales o he IPAS, we ha e u ilized BIS-11. The BIS-11 is a
sel - epo ques ionnai e o assessing gene al impulsi eness.
The cu en scale e sion con ains 30 i ems ha a e coded om
1 ( a ely/ne e ) o 4 (almos always/always). The le el o impul-
si eness is calcula ed by summing up he sco es o each i em.
All i ems we e de ined as iden i ying impulsi eness wi hin he
s uc u e o ela ed pe sonali y ai s. The ac o analysis e ealed
h ee componen s as ollows: “a en ional impulsi eness,” “mo o
impulsi eness,” and “non-planning impulsi eness.” Ins ead o a
unique o al sco e, he s udy o he indi idual con ibu ion o each
componen is ecommended. Findings epo an accep able/high
in e nal consis ency (C onbach’s alpha 0.79–0.82) o he scale
when applied o o ensic samples (28). The s uc u al p ope ies
o he BIS-11 we e eplica ed in Po uguese speaking samples (44).
Psychopa hy Checklis Re ised
To de e mine he di e gen alidi y o he IA and he PA sub-
scales o he IPAS, we ha e applied he PCL-R. The PCL-R is he
gold s anda d measu e o psychopa hy, ga he ing in o ma ion
om eco ds and a semi-s uc u ed in e iew (24, 25). The 20
i ems a e sco ed as absen (0), p esen o some deg ee (1), o
ully p esen (2), ha ing a maximum o al sco e o 40 poin s.
This ins umen may be conside ed a ou - ac o model comp is-
ing in e pe sonal, a ec i e, li es yle, and an isocial dimensions
(45). The in e pe sonal and a ec i e dimensions join ly se e as
second-o de ac o s ep esen ing he co e ai s o he psycho-
pa hic pe sonali y. Li es yle and an isocial ace s o m a supe -
o dina e ac o o social de iance (46). The wo second-o de
ac o s (Fac o 1 and Fac o 2) a e concomi an wi h he o iginal
ac o s uc u e epo ed o he i s edi ion o he PCL-R (47).
The s uc u al p ope ies o he PCL-R we e eplica ed in
Po uguese samples o he s anda d p o ocol, including eco d
e iew and s uc u ed in e iew (48). The PCL-R was applied by
an expe ienced psychia is (Jacin o Cos a Aze edo).
s a is ical analyses
S a is ical analyses we e conduc ed ollowing he me hodology
used in he p e ious IPAS alida ion s udies in adul s. The p in-
cipal componen analysis was conduc ed wi h no assump ions
ega ding he numbe o po en ial ac o s. Lau enschlage ’s
(49) ables we e used o de e mine he h eshold o signi ican
ac o s (minimum eigen alue o 2.0) and i em ac o load-
ings (minimum eigen alue o 0.40). In o de o assess ac o
s uc u e and maximize he eliabili y o ac o in e p e a ion,
an Oblimin o a ion was used so as o ob ain an oblique ac-
o solu ion o he o iginal ac o s (50). In e nal consis ency
was measu ed using C onbach’s alpha (51). Con e gen and
di e gen alidi y o he IPAS was es ed by examining he
Pea son’s p oduc -momen co ela ions wi h he s anda d-
ized measu es o impulsi i y and pe sonali y (BIS-11 and
PCL-R). Con i ma o y ac o ial analysis was es ed by calcula -
ing goodness-o - i indice, obus me hod (52).
The analyses we e ca ied ou using IBM SPSS S a is ics o
Windows, Ve sion 22.0 (A monk, NY, USA: IBM Co p.), and
wi h he S uc u al Equa ion P og am, EQS e sion 6.1 (53).
esUlTs
sample Desc ip ion
The sample comp ised 240 inma es wi h a mean (±SD) age o
35.4±8.4yea s; a o al o 67.1% (n=161) o he pa icipan s we e
single, and 58.3% did no ha e any child en (n=140). The mean
educa ion le el o he sample was 6.8±3.2yea s. The mean ime
in p ison ( ime spen behind ba s a he ime o assessmen ) o
he sample was 109.3±70.6mon hs. A o al o 45.8% (n=110)
o he inma es had been con ic ed o iolen c imes (physical
assaul , mu de , a emp ed mu de ). Valida ion p ocedu es we e
pe o med in he o al sample (n=240).
P incipal componen analysis
We ha e pe o med a p incipal componen analysis explo ing he
o iginal 30 i ems. Fi s , we inspec ed he Kaise –Meye –Olkin
Measu e o Sampling Adequacy (KMO=0.87) and eached he
conclusion ha i was an app op ia e alue. Second, we achie ed
a s a is ically signi ican Ba le ’s Tes o Sphe ici y (p<0.01).
Thi d, we ex ac ed wo ac o s (wi h an oblimin o a ion)
wi h eigen alues o 7.19 (Fac o 1, IA) and 3.29 (Fac o 2, PM)
accoun ing o 34.27 and 15.65% o o al a iance, espec i ely.
The IA ac o was composed o en i ems: 30, 27, 22, 9, 24, 15,
26, 4, 7, and 13. The PM ac o was composed o ele en i ems: 6,
14, 29, 28, 2, 23, 12, 16, 20, 10, and 1. The i ems 3, 5, 8, 11, 17, 18,
19, 21, and 25 we e excluded om he analysis as hey exhibi ed
componen loadings in e io o 0.40 (Table2).
con i ma o y Fac o ial analysis
To es he hypo hesis o wo dimensions, we use he con i ma o y
ac o analysis, o es he goodness-o - i indice, obus me hod.
Resul s showed a compa a i e i index o 0.90, and a oo mean
squa e e o o app oxima ion (RMSEA) o 0.06, 90% con idence
in e al (0.05, 0.08).
in e nal consis ency
The in e nal consis ency es o he dimensions ob ained in he
ac o analysis wi h he p esen sample e ealed a good C onbach’s
alpha alue o he IA ac o (0.89), and a good C onbach’s alpha
alue o he PM ac o (0.88) (Table2).
Reliabili y was also es ed ega ding he o iginal e sion o he
IPAS subscales. C onbach’s alpha o he IA o iginal subscale was
accep able (0.78), and i was good o he PM subscale (0.85).
TaBle 3 | Pea son co ela ions coe icien s be ween Impulsi e/P emedi a ed
Agg ession Scale (IPAS), Ba a Impulsi eness Scale, 11 h e sion (BIS-11), and
Psychopa hic Checklis Re ised (PCL-R).
iPas subscales
Measu es subscales ia PM
BIS-11 To al sco e 0.21** 0.20**
A en ional 0.14* 0.18*
Mo o 0.26** 0.27**
Non-planning 0.15* 0.06
PCL-R To al sco e 0.01 0.29**
In e pe sonal −0.14 0.24*
A ec i e −0.14 0.16*
Li es yle −0.07 0.22*
An isocial −0.07 0.21*
The s udy used 240 pa icipan s o co ela ions be ween IPAS and BIS-11; and a
subsample o 134 pa icipan s o co ela ions be ween IPAS and PCL-R.
IA, impulsi e agg ession; PM, p emedi a ed agg ession.
*p<0.05; **p<0.01.
TaBle 2 | Fac o loadings o Impulsi e/P emedi a ed Agg ession Scale (IPAS).
iPas i ems impulsi e P emedi a ed
30. Any hing could ha e se me o p io o
he inciden s
0.63 –
27. I was in a bad mood he day o he
inciden
0.66 –
22. I was con used du ing he ac s 0.79 –
9. I eel I los con ol o my empe du ing he
ac s
0.80 –
24. My beha io was oo ex eme o he le el
o p o oca ion
0.72 –
15. I became agi a ed o emo ionally upse p io
o he ac s
0.72 –
26. I conside he ac s o ha e been impulsi e 0.66 –
4. I ypically el guil y a e he agg essi e ac s 0.73 –
7. I usually can’ ecall he de ails o he inciden s
well
0.50 –
13. I eel some o he inciden s wen oo a 0.72 –
6. I eel my ac ions we e necessa y o ge wha
I wan ed
– 0.58
14. I hink he o he pe son dese ed wha
happened o hem du ing some o he inciden s
– 0.65
29. I am glad some o he inciden s occu ed – 0.64
28. The ac s we e a “ elease” and I el be e
a e wa d
– 0.75
2. I el my ou bu s s we e jus i ied – 0.70
23. P io o he inciden s I knew an al e ca ion
was going o occu
– 0.55
12. I wan ed some o he inciden s o occu – 0.80
16. The ac s led o powe o e o he s o
imp o ed social s a us o me
– 0.72
20. Some o he ac s we e a emp s a e enge – 0.75
10. Some imes I pu posely delayed he ac s un il
a la e ime
– 0.63
1. I planned when and whe e my ange was
exp essed
– 0.64
Eigen alues 7.19 3.29
Va iance (%) 34.27 15.65
C onbach’s alpha 0.89 0.88
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F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
cap u e impo an aspec s o he cons uc , as well as i s ele ance
o he p oposed use. The p esen esul s show app op ia e alidi y
o he Po uguese e sion o he IPAS.
The i ems o he ins umen we e adap ed acco ding o he
o iginal e sion (2). In ou sample, IPAS was able o demons a e
he p esence o wo ac o s: impulsi e and PM.
All he au ho s who s udied he alidi y o IPAS we e able
o educe he a iabili y o he scale o wo ac o s: IA and PM
ac o s. This is in line wi h he li e a u e on human agg ession
which a gues ha agg ession is no a single cons uc and should
be unde s ood as being composed o wo dimensions o ca ego-
ized in o wo di e en ypes: impulsi e o PM.
In he analysis o he explained a iance desc ibed by o he
au ho s, we ha e obse ed ha he IA ac o can explain be ween
12.9% (41) and 24% (39) o he o al IPAS a iance; and ha
he PM ac o can accoun o be ween 10.3% (42) and 15.6%
(37) o he o al IPAS a iance. We ha e ob ained highe alues
o explained a iance (34.3% o he IA ac o and 15.7% o
he PM ac o ). In he analysis o he IPAS in e nal consis ency
desc ibed by o he au ho s, we ha e obse ed ha i a ies
be ween 0.70 (41) and 0.93 (40) o he IA ac o ; and be ween
0.66 (41) and 0.90 (40) o he PM ac o . Ou alues o in e nal
consis ency and a iance can be explained by he homogenei y
o he sample.
Acco ding o Ben le and Douglas (52), when he goodness-
o - i and adjus ed goodness-o - i indexes a e highe han 0.90,
he analyses indica e adequa e i o he models. Also, acco ding
o Ben le and Douglas, when he RMSEA is less han. 0.10, he
analysis indica es adequa e i o he models.
In ou s udy, we ha e assessed he con e gen alidi y h ough
he analysis o Pea son p oduc -momen co ela ions coe icien s
be ween IPAS and BIS-11. We had signi ican co ela ions
be ween he IA subscale and he BIS-11 mo o ac i a ion, a en-
ion, and non-planning dimensions. We had signi ican co ela-
ions be ween he PM subscale and he BIS-11 mo o ac i a ion,
a en ion dimensions, bu no o non-planning dimension.
We ha e ound a sligh ly highe co ela ion be ween he o al
sco e o BIS-11 and IA han wi h he PM subscale o IPAS. Ou
con e gen and Di e gen Validi y
We ha e s udied he con e gence be ween he IPAS and he
BIS-11. The s a is ically signi ican co ela ions be ween he
wo scales (IPAS and BIS-11) and be ween i s dimensions a e
de ailed in Tabl e3, showing co ela ions wi h a en ional, mo o ,
and non-planning dimensions (2, 5, 28). Co ela ions we e
s a is ically signi ican , sugges ing he exis ence o con e gence
be ween he wo scales.
We ha e s udied di e gen alidi y h ough he analysis o co -
ela ions be ween IPAS and PCL-R in a subsample o 134 inma es.
The s a is ically signi ican co ela ions be ween he wo scales
(IPAS and PCL-R) and be ween i s dimensions a e de ailed in
Table 3. The IA subscale is no co ela ed wi h PCL-R. The PM
subscale is co ela ed wi h PCL-R in e pe sonal, li es yle, and
an isocial dimensions (p<0.05).
DiscUssiOn
Acco ding o AERA-APA-NCME (54), heo e ical and empi ical
pieces o e idence ha suppo he in e p e a ions o es sco es
a e undamen al so as o indica e he deg ee o which sco es

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Aze edo e al. IPAS Validi y in Po uguese Inma es
F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
esul s we e line wi h Ma hias and colleagues who epo ed
signi ican co ela ions be ween he IPAS subscales and BIS-11’s
o al sco e (co ela ions coe icien s o 0.39 o AI and 0.26 o
PM) (37).
Howe e , S an o d and colleagues ha e epo ed highe sig-
ni ican co ela ions be ween PM and he o al sco e o BIS-11
(co ela ion coe icien s o 0.21 o AI and 0.38 o PM) (2).
Ou da a e eal signi ican co ela ions be ween he h ee
dimensions o impulsi i y measu ed by BIS-11and IA subscale o
IPAS. Simila esul s we e epo ed by Chen and colleagues ha
ob ained signi ican alues o co ela ions be ween IA and he
h ee dimensions o BIS-11 (co ela ion coe icien s o 0.15 o
a en ional impulsi eness, 0.21 o mo o impulsi eness, and 0.12
o non-planning impulsi eness and AI) (41).
In he case o PM subscale o IPAS, we did no obse e
signi ican co ela ions wi h he non-planning dimension o
BIS-11. The same was epo ed by Chen and colleagues, who
only epo ed a signi ican co ela ion o 0.19 be ween PM and
a en ional impulsi eness (41).
We can explain hese esul s in h ee possible ways. Fi s , i
is assumed ha impulsi i y is ela ed agg ession, no doing any
disc imina ion be ween dimensions and ype o agg ession (33).
These esul s a e in acco dance wi h he hypo hesis ha impul-
si i y is ela ed and can be a p edisposing ac o o agg ession
(26). On he o he hand, we should no e ha he e a e impulsi e
indi iduals who a e no agg essi e, and he e o e, impulsi i y is
no he only ac o necessa y o he de elopmen o agg essi e-
ness (55). Second, since ou sample is composed o inma es, we
can assume a high p e alence o indi iduals wi h subs ance use
diso de s and ASPD (56). In hese ypes o pa hology, he e a e a
high exp ession o impulsi i y (57, 58).
Thus, we can explain he co ela ions be ween subscales o
IPAS and BIS-11 subscales because hey a e indi iduals wi h
g ea e impulsi i y con e ed by unde lying psychopa hology.
The hi d possible explana ion, ela ed o he non-planning
dimension o impulsi i y, is pe haps hose impulsi e indi iduals
who main ain planning abili y a e hose who can de elop and
lea n p emedi a ed agg essi e beha io . These indings suppo
he de ini ion o PM in which indi iduals wi h PM plan hei
ac ion and, hus, ha e ewe impai men s in ac ion planning
impulsi i y dimension (9). The non-planning dimension o
impulsi i y is ela ed o wo king memo y (59) and execu i e
unc ions, namely wi h he subscale o s a egic planning o he
execu i e unc ion index (60).
These esul s suppo he need o use o app op ia ed psy-
chome ic scales o he e alua ion o agg ession, in o de o go
beyond he assump ion ha indi iduals wi h highe le els o
impulsi i y a e mo e likely o display ex e nalizing beha io and
hus ha ing a g ea e p obabili y o showing agg essi e beha io .
This was he a ionale o he use o BIS-11 o he e alua ion
o con e gen alidi y wi h IPAS.
We ha e e alua ed he di e gen alidi y by analyzing co -
ela ions be ween AI and PM ac o s and PCL-R. As a esul ,
we ha e ob ained signi ican co ela ions o PM and PCL-R
in e pe sonal, li es yle, and an isocial dimensions, and no
signi ican co ela ions o AI and PCL-R. S an o d and col-
leagues, in 2008, e alua ed co ela ions be ween Psychopa hic
Pe sonali y In en o y (PPI) and he AI and PM ac o s, ha ing
ob ained signi ican ly highe alues o PPI in he indi iduals
ca ego ized as p emedi a ed agg esso s, ha is, ha ing highe
PM sco es (38).
These da a a e in ag eemen wi h he li e a u e on psychopa-
hy and he ype o agg essi eness ex e nalized by indi iduals
wi h highe exp ession o psychopa hic pe sonali y ai s.
Psychopa hy seems o be a isk ac o o PM, mainly in o ensic
samples (23).
Rega ding he gene aliza ion o esul s, some limi a ions
should be conside ed. Al hough we ha e wo ked wi h a la ge
sample, i is exclusi ely composed by men, he e o e we do no
know i agg essi e women will beha e in he same manne . The
pa icipan s a e subjec o long sen ences, making i di icul o
gene alize he esul s so as o include inma es wi h sho e sen-
ences. Also, pa icipa ion in his kind o esea ch in a o ensic
acili y con ex can change he way inma es espond o he IPAS.
We mus ake in o conside a ion ha he legal ci cums ances o
pa icipan s can modi y he ype o answe s. This sample was
ob ained in a p ison o con ic ed indi iduals, in No he n
Po ugal. We do no know whe he he scale psychome ic
cha ac e is ics a e he same in o he o ensic samples. In u u e
esea ch, i may be use ul o conside ools ha can ex e nally
quan i y he indi idual ac s o agg ession, such as he Modi ied-
O e Agg ession Scale.
eThics sTaTeMenT
The esea ch p o ocol was o mally app o ed by he E hics
Commi ee o Cen o Hospi ala de São João, Po o, Po ugal
(Documen numbe 48.14). W i en in o med consen was
ob ained a e he p ocedu es had been explained o pa icipan s,
in acco dance wi h he Decla a ion o Helsinki.
aUThO cOnT iBUTiOns
JA and MF-B con ibu ed o he concep ion o he s udy. The
da a analysis was ca ied ou by JA and JP. All au ho s con-
ibu ed o he in e p e a ion o he da a. JA and MF-B w o e
he manusc ip . All au ho s e ised he con en c i ically and
app o ed he inal e sion.
acKnOWleDgMenTs
We would like o hank Le ícia Mal a, MD, and Nu se João
Pin o o hei collabo a ion in he acquisi ion o he da a. We
would like o hank he Po uguese Gene al Di ec o a e o P ison
Se ices o au ho izing he esea ch.
FUnDing
The au ho s had no unding in he p epa a ion o his manusc ip .
7
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F on ie s in Psychia y | www. on ie sin.o g Feb ua y 2018 | Volume 9 | A icle 10
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