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Insomnia in highe educa ion: P e alence, alida ion, and
measu emen in a iance in medical sciences s uden s
Zah a Nejad-Eb ahim Soumee1, Ami hossein Rasouli1, Ha e Ti ga i Se aji2, Sima Jahanbakhsh3,
Omid Saed4*
1S uden Resea ch Commi ee, Depa men o Clinical Psychology, School o Medicine, Zanjan Uni e si y o Medical Sciences, Zanjan,
I an
2Depa men o Psychology, Facul y o Educa ional Sciences and Psychology, Uni e si y o Mohaghegh A dabili, A dabil, I an
3S uden Resea ch Commi ee, School o Medicine, Zanjan Uni e si y o Medical Sciences, Zanjan, I an
4Depa men o Clinical Psychology, School o Medicine, Zanjan Uni e si y o Medical Sciences, Zanjan, I an
A icle in o Abs ac
In oduc ion
Insomnia is a widesp ead heal h issue, as i is one o he
mos commonly epo ed heal h complain s and he mos
common sleep diso de [1]. Sleeping diso de s a e
es ima ed o a ec 15-35% o he gene al public, and
app oxima ely 30% o medical s uden s [2]. A
comp ehensi e analysis o se en s udies ound ha
insomnia a ec s a signi ican po ion o s uden s, wi h
p e alence a es anging om 9.4% o 38.2% [3].
Mo eo e , Yassin e al. [4] epo ed an insomnia
p e alence o 18.3% among medical s uden s. Insomnia
mani es s as a ange o sleep dis u bances, including
di icul y in alling asleep, s aying asleep, waking up oo
ea ly, o expe iencing unsa is ac o y sleep quali y.
Addi ionally, pa ien s diagnosed wi h insomnia mus
also epo expe iencing impai men in hei e e yday
unc ioning as a ou come o hei sleep di icul ies [5].
Insomnia diso de is usually accompanied by a wide
ange o nega i e heal h ou comes and ele a es he
likelihood o de eloping di e se psychological issues
and challenges, including dep ession and anxie y [6].
Insomnia also signi ican ly impai s academic
pe o mance [7]. A c oss-sec ional s udy o a ound
Nejad-Eb ahim Soumee e al. J Med Edu De . 2025; 18(1): 32-41 Jou nal o Medical Educa ion De elopmen
Backg ound & Objec i e: Insomnia, a widesp ead sleep diso de , impac s 15-35% o he
gene al popula ion and a conce ning 30% o medical sciences s uden s. This s udy aims o
assesses he psychome ic p ope ies, ac o s uc u e and measu emen in a iance o he
Insomnia Se e i y Index (ISI) in I anian medical uni e si y s uden s.
Ma e ials & Me hods: This c oss-sec ional s udy included 370 medical uni e si y s uden s
(54.9% emales). A e p o iding a de ailed in oduc ion ega ding he pu pose o he s udy and
ecei ing pa icipan s' consen online, hey we e eques ed o ill ou he Insomnia Se e i y
Index (ISI) and Pi sbu gh Sleep Quali y Index (PSQI). Con i ma o y ac o analysis and
hie a chical eg ession analysis we e used o examine he ac o s uc u e and p edic insomnia
se e i y.
Resul s: The esul s o desc ip i e s a is ics showed ha he p e alence o clinical insomnia
was 22.6% in male and 27.9% in emale s uden s, and 62.2% o male and 67.5% o emale
s uden s had poo sleep quali y. CFA showed ha he one- ac o model wi h all i ems was he
mos sui able s uc u e (x2 = 13.82, d = 9, GFI = 0.990, CFI = .994, TLI = 0.986, RMSEA =
0.038). The s udy's indings indica e ha he ISI exhibi s measu emen in a iance ac oss
gende s, ensu ing i s unbiased applica ion o bo h male and emale popula ions. Fu he mo e,
his scale demons a ed accep able eliabili y and alidi y. Finally, he esul s o hie a chical
eg ession analysis indica ed ha he poo sleep quali y was a signi ican p edic o o insomnia
se e i y (β = 0.389).
Conclusion: The Pe sian e sion o ISI showed s ong alidi y and eliabili y. These indings
indica e ha insomnia se e i y could be measu ed adequa ely in I anian samples using he ISI.
Keywo ds: medical s uden s, insomnia diso de , p e alence s udy, psychome ics
*Co esponding au ho :
Omid Saed, Commi ee, Depa men
o Clinical Psychology, School o
Medicine, Zanjan Uni e si y o
Medical Sciences, Zanjan, I an
Email: [email protected]
O iginal A icle
A icle his o y:
Recei ed 15 Jun. 2024
Accep ed 2 Feb. 2025
Published 14 Ap . 2025
How o ci e his a icle:
Nejad-Eb ahim Soumee Z, Rasouli
A, Ti ga i Se aji H, Jahanbakhsh S,
Saed O. Insomnia in highe
educa ion: P e alence, alida ion,
and measu emen in a iance in
medical sciences s uden s. J Med Edu
De . 2025; 18(1): 32-41.
[ DOI: 10.61186/edcj.18.1.32 ] [ Downloaded om edujou nal.zums.ac.i on 2025-10-03 ]
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Nejad-Eb ahim Soumee e al.: Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
medical sciences s uden s
Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1¦ 2025 33lopmen ¦
Volume 17 ¦ Issue 54¦ 2024
50,000 No wegian s uden s showed ha sleeping less
han 5 hou s and mo e han 10 hou s, compa ed o hose
sleeping 7 o 9 hou s, is associa ed wi h ailing exams
[8]. In gene al, day ime sleepiness, low le els o
a en ion, and impai ed memo y/decision-making ha
a ise om sleep dep i a ion can p o ide a sui able
explana ion o poo academic pe o mance [9]. Hea y
academic wo kload, p o essional a i udes and habi s, as
well as poo awa eness o sleep hygiene a e among he
ac o s ha educe he du a ion and quali y o sleep, in
medical s uden s, consequen ly leading o hei poo
academic pe o mance [10].
Gi en he consequences o insomnia discussed o
s uden s, he exis ence o a ins umen o diagnose and
assess his diso de in he s uden popula ion seems
necessa y. Al hough polysomnog aphy has eme ged as a
c ucial ins umen in he assessmen o many sleep
diso de s, i is no he ecommended app oach o
diagnosing insomnia [5]. Consequen ly, he diagnosis o
insomnia elies p ima ily on he indi idual's sel -
epo ed expe iences and symp oms. While s uc u ed
and semi-s uc u ed clinical in e iews a e becoming
mo e commonly u ilized in clinical se ings, hese
me hods a e highly ime- consuming and necessi a e
ex ensi e knowledge abou sleep diso de s. As a esul ,
he e is a need o simple and e icien ins umen s o
measu e he se e i y o insomnia in o de o acili a e he
diagnos ic p ocess [11]. The Insomnia Se e i y Index
(ISI) is a sel -adminis e ed ques ionnai e ha cap u es
wo o he mos common insomnia complain s: di icul y
alling asleep and equen nigh ime awakenings [12].
The ISI, de eloped in 1993, has eme ged as a aluable
ins umen in bo h clinical p ac ice and esea ch s udies,
also he ISI demons a es alidi y o use ac oss a b oad
age ange, and i has p o en o be a aluable assessmen
ins umen o indi iduals wi h di e se condi ions,
including man al diso de s [13], and o he clinical
p oblems [14]. Psychome ic e alua ions o he ISI ha e
been conduc ed o he English [15], F ench [16],
Spanish [17], and Chinese [18] e sions, and s udies
ha e consis en ly demons a ed he ins umen 's
eliabili y and adequa e concu en alidi y wi h o he
sleep assessmen measu es. In I an, he psychome ic
cha ac e is ics o o he ools in he ield o sleep,
including Pi sbu gh Sleep Quali y Index [19] and
e ised Adolescen Sleep Hygiene Scale [20], ha e been
examined. These ools espec i ely add ess indi iduals'
pe cep ions o hei sleep quali y and sleep hygiene
beha io s, bu none assess he se e i y o insomnia.
The e o e, he ad an age o he ISI is i s di ec
measu emen o insomnia se e i y. Howe e , he e is no
alida ion o he Pe sian e sion o his ques ionnai e in
he popula ion o I anian medical sciences s uden s.
Hence, he pu pose o he p esen s udy is o examine he
ac o s uc u e, psychome ic p ope ies, and
measu emen in a iance o he ISI ques ionnai e in he
popula ion o I anian medical sciences s uden s.
Ma e ials & Me hods
Design and se ing(s)
This c oss-sec ional, psychome ic s udy in es iga ed he
ISI among Bachelo , Pos g adua e, and PhD s uden s a
Zanjan Uni e si y o Medical Sciences, I an. The
Resea ch E hics Commi ee o he Zanjan Uni e si y o
Medical Sciences app o ed he s udy (App o al ID:
IR.ZUMS.REC.1396.35).
Pa icipan s and sampling
All pa icipan s o his s udy we e I anian and Pe sian-
speaking, and we e selec ed using con enience
sampling. In a ious s udies, di e en sugges ions ha e
been made o de e mining he app op ia e sample size
o psychome ic s udies. These sugges ions ange om
5 o 20 pa icipan s pe i em [21]. In he p esen s udy,
50 pa icipan s pe i em we e used. The inclusion c i e ia
o his s udy included in o med consen and an age
ange o 18 o 50 yea s. The exclusion c i e ion was a
desi e o wi hd aw om he s udy o andom esponse o
he i ems.
Tools/Ins umen s
The ollowing ques ionnai es we e used o da a
collec ion, (ISI): The ISI is a 7-i em ques ionnai e ha
measu es he se e i y o insomnia expe ienced o e he
pas wo weeks. I is he mos widely used ins umen in
esea ch o assessing insomnia se e i y . Each i em is
a ed on a 5-poin Like scale, wi h sco es anging om
0 o 28. Highe sco es indica e g ea e se e i y o sleep
dis u bances and associa ed day ime symp oms. The
ISI's alidi y and eliabili y ha e been con i med in
a ious s udies [22]. The Pi sbu gh Sleep Quali y Index
(PSQI): The PSQI is a sel -adminis e ed ques ionnai e,
de eloped by Buysse e al. [23], ha assesses sleep
quali y o e he pas mon h. The ques ionnai e consis s
o 19 ques ions/i ems o ganized in o se en componen s.
Each componen is sco ed om 0 o 3, esul ing in a
global sco e anging om 0 o 21. A global sco e
exceeding 5 indica es poo sleep quali y. The PSQI has
been alida ed in a ious coun ies and demons a ed
good eliabili y and alidi y in bo h clinical and non-
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34 Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1 ¦ 2025
clinical samples [24]. In I an, Shadzi e al. examined he
eliabili y and alidi y o his ques ionnai e, among
medical s uden s and epo ing sa is ac o y psychome ic
p ope ies [25].
Da a collec ion me hods
To ensu e accu a e ansla ion, he Pe sian e sion o he
ISI was p epa ed in acco dance wi h in e na ional
guidelines o c oss-cul u al adap a ion o sel - epo
measu es [26]. A eam o expe s, including a clinical
psychologis and a psychia is , ansla ed he ISI i ems
in o Pe sian. Subsequen ly, an English language expe
conduc ed a back- ansla ion in o English o ensu e he
accu acy and comple e alignmen o he Pe sian and
English e sions [27]. Following se e al ounds o
e iew and e inemen o add ess any g amma ical o
con en - ela ed conce ns, he ansla ed Pe sian e sion
o he ISI was inalized and p epa ed o implemen a ion,
main aining close alignmen wi h he o iginal English
ins umen . Sampling was conduc ed h ough he online
pos ing o b ie explana ions o he pu pose o his
esea ch, along wi h a pa icipa ion link, on uni e si y
social media ne wo ks. Be o e comple ing he scale,
pa icipan s we e p o ided wi h in o med i ual
consen . Following da a collec ion, he esponses we e
sc eened o alidi y. Ou lie s we e iden i ied using
Mahalanobis dis ance, and in alid esponses we e
lagged. In alid esponses included ixed and
con adic o y esponses.
Da a analysis
The i s s ep in he analysis was o conduc a desc ip i e
analysis o he da a o unde s and he dis ibu ion o
demog aphic a iables, insomnia se e i y, and sleep
quali y in s uden s. his in ol ed equency dis ibu ions
and g aphical ep esen a ions we e used o isualize he
da a. To in es iga e he ac o s uc u e o he ISI, CFAs
we e conduc ed ollowing an explo a o y ac o analysis.
Th ee models we e es ed: a single- ac o model wi h 7
i ems, a wo- ac o model wi h 7 i ems, and a h ee- ac o
model wi h 7 i ems. Model i was assessed using he
ollowing indices: chi-squa e i s a is ics (CMIN/DF),
inc emen al i index (IFI), Tucke -Lewis index (TLI),
compa a i e i index (CFI), and oo mean squa e e o
o app oxima ion (RMSEA, 90% CI). goodness o i
was de ined as CMIN/DF ≤ 3, TLI, IFI, and CFI ≥ 0.900,
and RMSEA ≤ 0.05 [28]. Measu emen in a iance was
employed o assess he deg ee o in a iance be ween
gende s ( emales s. males). Measu emen in a iance
was assessed o de e mine he ex en o which he ISI
exhibi s equi alen psychome ic p ope ies ac oss
gende s. This analysis e alua es whe he he cons uc o
in usi e hough app aisals is measu ed in he same way
o bo h gende s, ensu ing he eliabili y and alidi y o
compa isons ac oss g oups. Measu emen in a iance
was es ed using a se ies o inc easingly cons ained
models including Con igu al, Me ic, and Scala . Model
i was compa ed using he change in CFI (ΔCFI) and
RMSEA (ΔRMSEA) be ween he less es ic i e and
mo e es ic i e models. Cu o alues o accep able
in a iance we e ΔRSMEA ≤ 0.015 and ΔCFI ≤ 0.01[29].
To assess he ques ionnai e in e nal consis ency,
C onbach's alpha was calcula ed. Fu he mo e, he
c i e ion alidi y was assessed by examining i s
co ela ions wi h sleep quali y measu e. The da a we e
analyzed using SPSS e sion 27 o desc ip i e s a is ics,
and AMOS e sion 24 o Con i ma o y Fac o Analysis
(CFA).
Resul s
As shown in Table 1, a o al o 370 s uden s pa icipa ed
in he s udy, wi h 45.1% (n = 167) being male and 54.9%
(n = 203) being emale. The mean age o he pa icipan s
was 23.79 yea s (SD = 4.48), wi h ages anging om 18
o 51 yea s. Mos pa icipan we e single (91.6% o men;
75.4% o women). In e ms o educa ional s a us, 73.1%
o men and 29% o women we e pos g adua e s uden s.
The p e alence o clinical insomnia was 22.6% in men
and 27.9% in women. In addi ion, 37.8% o men and
32.5% o women had good sleep quali y.
Table 1. Sociodemog aphic and clinical a iables acco ding o
gende
Men
(n=167)
Women
(n=203)
n
%
n
%
Ma i al s a us
Single
153
91.6
153
75.4
Ma ied / In ela ionship
14
8.4
50
24.6
Educa ional a ainmen
Unde g adua e
45
26.9
144
71
Pos g adua e
122
73.1
59
29
Insomnia se e i y
Non-clinical
58
34.8
64
31.6
Sub-clinical
71
42.6
83
40.8
Mild-clinical
37
22
50
24.6
Se e -clinical
1
0.6
6
3
Sleep quali y
PSQI sco e < 5
63
37.8
66
32.5
PSQI sco e > 5
104
62.2
137
67.5
Age mean (SD)
24.59 (4.35)
23.13 )4.48)
Abb e ia ions: SD, s anda d de ia ion; PSQI, Pi sbu gh sleep quali y index; n
and %, sample size and pe cen ages.
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Nejad-Eb ahim Soumee e al.: Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
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Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1¦ 2025 35
Table 2 displays he mean, s anda d de ia ion, skewness,
ku osis, and C onbach's alpha o he i ems. he
dis ibu ion o samples based on he ku osis and
skewness o he i ems does no exceed he s anda d ange
o +2. The co ec ed i em- o al co ela ion indica es a
mode a e and signi ican ela ionship be ween he i ems
and he o al sco e. The in e nal consis ency coe icien s
based on C onbach's alpha did no exceed 0.80 a e
emo ing any o he i ems. Pa icipan s esponded o all
ques ionnai e i ems in a nea ly uni o m manne , and he
dispe sion was low.
CFA was conduc ed using Amos e sion 24. To u he
assess and alida e he ac o s uc u es iden i ied in
explo a o y ac o analysis, CFA was pe o med. The
examina ion o he esul s showed ha he one- ac o
model exhibi ed he bes and mos app op ia e i indices.
The esul s o he CFAs a e p esen ed in Table 3. As
shown in Table 3, he inal ull-i em model, has he
ollowing cha ac e is ics x2 = 13.82, d = 9, GFI = 0.990,
CFI = 0.994, TLI = 0.986, RMSEA = 0.038. In he inal
one- ac o model, he pa h coe icien s o each i em wi h
i s unde lying ac o ange om 0.49 o 0.81. This
indica es ha each i em has an accep able p edic i e
weigh wi h i s main ac o . Table 2 displays he ac o
loadings o he i ems. Acco ding o, he ac o loading
alues o he i ems we e abo e 0.596, anging om 0.596
in i em 3 o 0.815 in i em 2.
Table 3 p esen s he esul s o he measu emen
in a iance es ing o he single- ac o model. The model
displayed sa is ac o y i indices o bo h males and
emales, as indica ed by he TLI, CFI, and RMSEA.
Addi ionally, he con igu al, me ic, and scala
in a iance models es ed be ween gende g oups showed
sa is ac o y i indices based on he TLI, CFI, and
RMSEA. Only he con igu al in a iance models
exhibi ed minimal deg ada ion in model i (Δx2 =
15.428; p = - 0.042; ΔCFI = - 0.012; ΔTLI = - 0.013;
ΔRMSEA = 0.007), as well as be ween he me ic and
scala in a iance models (Δx2 = 1.954; p= - 0.001; ΔCFI
= - 0.001; ΔTLI = - 0.001; ΔRMSEA = < 0.001).
Consequen ly, in a iance was es ablished ac oss bo h
gende s.
Table 2. I em-Le el s a is ics and ac o s uc u e o he ISI (n = 370)
I ems
Mean
(SD)
Skewness
Ku osis
Co ec ed i em- o al
C onbach’s α i dele ed
Fac o loading
1a. Di icul y alling
asleep
1.16 (1.06)
0.68
- 0.21
0.56
0.79
0.700
1b. Di icul y s aying
asleep
1.04 (1.05)
0.88
0.18
0.50
0.80
0.644
1c. P oblem waking
up oo ea ly
1.61 (1.26)
0.36
- 0.90
0.48
0.80
0.625
2. Sleep sa is ac ion
1.72 (1.02)
0.26
- 0.44
0.70
0.76
0.815
3. In e e ence
2.09 (1.10)
- 0.09
-.72
0.45
0.80
0.596
4. No iceabili y
1.61 (1.09)
0.21
- 0.83
0.54
0.79
0.677
5. Dis ess
1.18 (1.09)
0.62
- 0.49
0.65
0.77
0.770
Eigen alues
3.367
Pe cen age o a iance
48.10
Abb e ia ions: SD, s anda d de ia ion.
No e: The loadings indica e he s eng h o he ela ionship be ween each i em and i s espec i e ac o . Eigen alue ep esen s he eigen alue associa ed wi h each ac o .
Pe cen age o a iance indica es he p opo ion o a iance explained by each ac o . C onbach's alpha alue ep esen s he eliabili y coe icien . Co ec ed coe icien
indica es he C onbach's alpha alue a e he emo al o each i em. skewness and Ku osis measu e he shape o he dis ibu ion. M signi ies he a e age esponse o each
i em. SD ep esen s he s anda d de ia ion o esponses.
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Nejad-Eb ahim Soumee e al. Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
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36 Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1 ¦ 2025
Table 3. Fi s a is ics o he con i ma o y ac o analysis model and Measu emen in a iance (n = 370)
Model
X2
d
GFI
CFI
TLI
RMSEA
Fac o s uc u e in a iance
 Model 1. 1- ac o ull-i em ISI
13.825
9
0.990
0.994
0.986
0.038
 Model 2. 2- ac o ull -i em ISI
28.737
11
0.978
0.978
0.957
0.066
 Model 3. 3- ac o ull -i em ISI
42.597
9
0.968
0.958
0.901
0.101
Measu emen in a iance
χ2 (d )
P
CFI
TLI
RMSEA (90% CI)
 Con igu al in a iance
28.383 (18)
0.050
0.987
0.970
0.970
0.040 (0.000; 0.066)
 Me ic in a iance
43.811 (24)
0.008
0.975
0.957
0.957
0.047 (0.024; 0.069)
 Scala in a iance
45.756 (25)
0.007
0.974
0.956
0.956
0.047 (0.025; 0.069)
No e: p < 0.05 indica es signi icance a he 5% le el, and p < 0.01 indica es signi icance a he 1% le el.
Abb e ia ions: X², chi-squa e s a is ic; d , deg ees o eedom; GFI, goodness o i index; CFI, compa a i e i index; TLI, Tucke -Lewis index; RMSEA,
oo mean squa e e o o app oxima ion; P, p- alue o he chi-squa e es o in a iance; CI, con idence in e al.
Con e gen alidi y was assessed using he A e age
Va iance Ex ac ed (AVE) index. An AVE alue g ea e
han 0.5 is gene ally conside ed accep able. In he
p esen s udy, he AVE was es ima ed o be 0.51. In o de
o assess C i e ion alidi y o he 7-i em ISI, we analyzed
he co ela ion be ween i s o al sco e wi h o he sleep-
ela ed scales. The esul s demons a e ha he
ela ionship be ween he o al sco e o he ISI wi h
Pi sbu gh Sleep Quali y Index, show signi ican
co ela ions, anging om weak o mode a e ( = 0.52 p
< 0.01). In e nal consis ency and composi e eliabili y
we e used o assess he eliabili y o he p esen
ques ionnai e.
Figu e 1. The inal model
Acco ding o he esea ch indings, he Composi e
Reliabili y (CR) was calcula ed o be 0.865, and he
C onbach's alpha was 0.813. These esul s indica e ha
he ques ionnai e has adequa e eliabili y in he I anian
popula ion. A hie a chical Mul iple eg ession analysis
was conduc ed o examine he con ibu ion o Sleep
Quali y in p edic ing sleep- ela ed p oblems (Table 4).
In his in es iga ion, he se e i y o insomnia was
examined as he esul a iable, wi h demog aphic
ac o s and Sleep Quali y se ing as p edic o s. The
eg ession analysis was ca ied ou in a wo-s ep p ocess.
In he i s s ep age, gende and ma i al we e en e ed in o
he model. The esul s indica ed ha none o hem can
signi ican ly p edic ed insomnia se e i y. In he second
s ep, age, gende , ma i al, and Sleep Quali y we e
en e ed in o he model. The esul s showed ha in his
s ep, only Sleep Quali y (β = 0.389) signi ican ly
p edic ed insomnia se e i y. This sugges s ha o each
0.389 uni ise in PSQI, e ealing o poo sleep quali y,
he e is a co esponding one-uni inc ease in he se e i y
o insomnia. The R2 alue o he eg ession models in
he wo s eps we e 0.006 and 0.395, espec i ely
ep esen ing ha he inal model p edic s 38.9% o he
insomnia se e i y.
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Nejad-Eb ahim Soumee e al.: Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
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Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1¦ 2025 37
Table 4. Hie a chical eg ession model o insomnia se e i y
R
R2
R2 change
B
SE
β
Sig.
S ep 1
0.079
0
0.006
0.512
Age
0.035
0.068
0.029
0.513
0.608
Gende
0.698
0.585
0.066
1.193
0.234
Ma i al
0.331
0.807
0.024
0.410
0.682
S ep 2
0.395
0.156
0.150
< 0.001
Age
0.024
0.062
0.020
0.381
0.703
Gende
0.350
0.541
0.033
0.646
0.519
Ma i al
0.569
0.745
0.041
0.763
0.446
Sleep
quali y
1.03
0.128
0.389
8.060
< 0.001
Abb e ia ions: R, co ela ion coe icien ; R², coe icien o de e mina ion; R² change, change in R² when a new a iable is added o he model; B, uns anda dized eg ession
coe icien ; SE, s anda d e o ; β, s anda dized eg ession coe icien ; , -s a is ic; Sig, Signi icance le el.
Discussion
The aim o he p esen esea ch was o examine he
psychome ic cha ac e is ics, ac o ial s uc u e, and
measu emen in a iance o he Insomnia Se e i y Index
among I anian medical sciences s uden s. The ISI
demons a ed app op ia e in e nal eliabili y and
con e gen alidi y. The indings sugges ed ha he
single- ac o model p o ed o be he mos sui able model
in he s uden sample, aligning wi h p e ious esea ch
ou comes.
The cu en esea ch demons a es ha clinical insomnia
a ec ed 22.6% o male s uden s and 27.9% o emale
s uden s. This ou come aligns wi h he indings o he
me a-analysis s udy ca ied ou by Zeng e al. [30], which
e ealed a highe occu ence o insomnia among emale
s uden s as compa ed o male s uden s. The explana ions
o he highe p e alence o insomnia in women,
especially emale s uden s, seem o be mul i ac o ial
[30]. In gene al, women end o be mo e exposed o
un a o able socioeconomic condi ions, such as acqui ing
lowe income o a aining lowe educa ional le els [31],
and he e o e emale s uden s may expe ience mo e
s ess ega ding hei u u e and ca ee . Fu he mo e,
women a e mo e likely o ace psychia ic p oblems like
dep ession and anxie y [32], which se e as isk ac o s
o insomnia in women. As a esul , emale s uden s
expe ience g ea e emo ional dys unc ion and epo
mo e insomnia.
Fu he mo e, he esul s showed ha 62.2% o male
s uden s and 67.5% o emale s uden s had poo sleep
quali y. In gene al, ca eine consump ion, s ess, and
i egula sleep-wake pa e ns can dec ease sleep quali y,
and men al heal h issues (such as dep ession, psychia ic
diso de s, pe cei ed s ess, and anxie y) a e undoub edly
de imen al o sleep quali y [33]. Gi en ha s uden s may
s ay up la e a nigh and wake up ea ly due o academic
demands and social in e ac ions, and end o sleep mo e
on holidays, hei sleep-wake pa e ns a e i egula .
Addi ionally, due o academic and wo k- ela ed issues,
s uden s expe ience high le els o s ess. Fu he mo e,
du ing exam pe iods, s uden s may inc ease hei
ca eine consump ion o s ay mo e ale and awake. As a
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Nejad-Eb ahim Soumee e al. Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
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38 Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1 ¦ 2025
esul o all hese ac o s, he sleep quali y o s uden s
dec eases. Mo eo e , he gende di e ences in sleep
quali y p oblems a e mainly a ibu ed o he
p io i iza ion o emo ional diso de s and socioeconomic
inequali ies [34], which lead o highe le els o
expe ienced s ess. The suscep ibili y o women o poo
sleep quali y may also s em om gende -based
di e ences in sleep biology, which a e exace ba ed by
he highe le els o emo ional diso de s in women [35].
The e o e, all o hese ac o s syne gis ically con ibu e
o a g ea e educ ion in he sleep quali y o emale
s uden s compa ed o male s uden s.
The indings indica ed ha he ISI is a eliable ins umen
o assessing he se e i y o insomnia in he I anian
medical s uden popula ion. Speci ically, he esul s
demons a ing he good in e nal consis ency o his scale
a e consis en wi h he indings om p e ious esea ch
[36]. In his s udy, h ee models we e es ed: one, wo,
and h ee- ac o model (wi hou i em dele ion). The
esul s o he CFA indica ed ha he one- ac o model
was he mos app op ia e model o he I anian medical
sciences s uden popula ion, accoun ing o 48.10% o
he o al a iance o he ques ionnai e. This inding is
consis en wi h he esul s o s udies in Sweden [37], and
he Uni ed S a es [36], bu inconsis en wi h o he s udies
(11, 38). In explaining his inding, i can be said ha in
he p esen s udy, he wo- ac o and h ee- ac o models
we e also ai ly sui able, bu he one- ac o model was
he bes and mos app op ia e model o explaining he
Insomnia Se e i y Index in he I anian medical s uden
popula ion. Addi ionally, he linguis ic and cul u al
di e ences be ween he I anian popula ion and he
popula ions o o he s udies can be men ioned.
The measu emen in a iance implies ha he ISI can be
u ilized in a su icien ly unbiased manne among bo h
male and emale esponden s. Pu nick and Bo ns ein [39]
ha e sugges ed ha scala measu emen in a iance
analyses se e as dynamic and in o ma i e e alua ions
o a cons uc 's unc ioning ac oss g oups, a he han
se ing as ga eway es s. These esul s con ibu e o he
g owing body o li e a u e on he psychome ic
obus ness o he ISI and unde sco e i s c oss-gende
applicabili y. Fu he mo e, he esul s indica ed ha he
Pe sian e sion o he ISI (ISI-P) had sa is ac o y
con e gen alidi y (signi ican posi i e co ela ion)
wi h he sleep quali y measu emen ins umen , = 0.52,
p < 0.001. This psychome ic p ope y is aligns wi h he
indings o p e ious s udies [17].
The esul s o he hie a chical eg ession analysis poin
o he p edic i e ole o sleep quali y in he se e i y o
insomnia (β = 0.389). This indica es ha sleep quali y
accoun s o 38.9% o he a iance in insomnia se e i y.
The PSQI, used in ou s udy o measu e sleep quali y, has
been widely alida ed and shown o be e ec i e in
assessing a ious dimensions o sleep quali y, including
subjec i e sleep quali y, sleep du a ion, sleep la ency,
sleep dis u bances, habi ual sleep e iciency, and
day ime dys unc ion [23]. Poo sco es on hese
dimensions we e signi ican ly co ela ed wi h highe ISI
sco es, indica ing mo e se e e insomnia. This is align
wi h p e ious s udies ha ha e ound a s ong
ela ionship be ween sleep quali y, as measu ed by he
PSQI, and insomnia se e i y [40].
In examining he b oade implica ions o hese indings,
i is essen ial o conside he mul i ace ed na u e o sleep
quali y and i s de e minan s. Fac o s such as sleep
hygiene, psychological s ess, academic wo kload, and
li es yle habi s can signi ican ly in luence sleep quali y.
In o he wo ds, p ac ices ha comp omise good sleep
hygiene, such as ex ensi e sc een usage be o e bed,
inconsis en sleep schedules, and excessi e ca eine
in ake, can wo sen sleep quali y and heigh en he isk o
de eloping insomnia [41]. Mo eo e , psychological
ac o s play a c i ical ole in sleep quali y. The e is a
s ong connec ion be ween s ess, anxie y, and
dep ession, as well as poo sleep quali y and insomnia.
Resea ch has ound ha people wi h highe s ess le els
and nega i e a ec a e mo e p one o expe iencing poo
sleep quali y and, in u n, de eloping mo e p onounced
insomnia [15]. The in e play be ween psychological
ac o s and sleep quali y sugges s ha in e en ions
aimed a educing s ess and imp o ing men al heal h
could be e ec i e in mi iga ing insomnia se e i y.
This s udy had a ew limi a ions such as did no
con oling o medica ion ea men in he sample da a.
Fu u e s udies can add ess his ac o . The con e gen
alidi y o he ISI-P scale was assessed using only one
measu emen ins umen . The s udy elied on a single
sou ce o da a (sel - epo ) o e alua ing insomnia
se e i y. Fu u e esea ch could conside inco po a ing
addi ional measu es, such as sleep dia ies o objec i e
sleep assessmen s, o p o ide a mo e comp ehensi e
e alua ion. Despi e hese limi a ions, he indings
con ibu e o he g owing body o e idence suppo ing
he psychome ic p ope ies o he ISI in he I anian
medical s uden popula ion.
Conclusion
In his s udy, he c oss-cul u al adap a ion o he ISI was
igo ously conduc ed in acco dance wi h es ablished
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Nejad-Eb ahim Soumee e al.: Insomnia in highe educa ion: P e alence, alida ion, and measu emen in a iance in
medical sciences s uden s
Jou nal o Medical Educa ion De elopmen ¦ Volume 18 ¦ Issue 1¦ 2025 39
guidelines, and i s ac o s uc u e, psychome ic
p ope ies and measu emen in a iance we e examined
in a sample o I anian medical sciences s uden s. The
esul s o his s udy s eng hen he psychome ic alidi y
o he ISI and u he ein o ce i s s uc u al alidi y.
Addi ionally, he esul s o he eg ession analysis
showed ha sleep quali y is he bes p edic o o
insomnia se e i y. O e all, he indings o his s udy can
acili a e u u e esea ch and clinical in e en ions
ela ed o he se e i y o insomnia. Howe e , u he
s udies a e needed o deepen ou unde s anding o
insomnia se e i y and i s ela ionship wi h o he
a iables ha impac indi idual unc ioning.
E hical conside a ions
The Resea ch E hics Commi ee o he Zanjan Uni e si y
o Medical Sciences (ZUMS), in Zanjan, I an app o ed
he s udy (App o al ID: IR.ZUMS.REC.1402.176). All
pa icipan s ga e w i en in o med consen , and hey
could wi hd aw om he s udy a any s age.
A i icial in elligence u iliza ion o a icle
w i ing
The au ho s decla e ha hey did no use gene a i e
A i icial In elligence (AI) and AI-assis ed echnologies
in he w i ing p ocess o his pape .
Acknowledgmen s
The au ho s wan o hank all s uden s o Zanjan
Uni e si y o Medical Sciences (I an) who ac i ely
pa icipa ed in his s udy.
Con lic o in e es s a emen
The au ho s ha e no con lic s o in e es o decla e
Au ho con ibu ions
ZNE, AR and OS and designed, conduc ed he s udy,
pe o med he s a is ical analyses, and w o e he
manusc ip . HTS pa icipa ed in he design and
coo dina ion and helped o d a he manusc ip . All
au ho s ead and app o ed he inal manusc ip
Funding
Zanjan Uni e si y o Medical Sciences has inancially
suppo ed his s udy.
Da a a ailabili y s a emen
Da a will be made a ailable on eques .
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