Development and Psychometric Testing of a New Short-Form of the Premenstrual Symptoms Questionnaire (PSQ-S)

Figures & data

Figure 1 Flow chart of the study.

Abbreviations: PSQ, Premenstrual Symptoms Questionnaire; PMDD, premenstrual dysphoric disorder; SSS-8, Somatic Symptom Scale-8; NRS, numerical rating scale.

Table 1 Characteristics of the Study Participants (n = 922)

Characteristic
Age (years), mean (SD)	16.7 (0.9)
School year, number (%)
First year	308 (33.4)
Second year	296 (32.1)
Third year	315 (34.2)
Missing	3 (0.3)
Age at menarche (years), mean (SD)	12.0 (1.4)
Height (m), mean (SD)	157.9 (5.2)
Body weight (kg), mean (SD)	51.2 (6.9)
Menstrual pain intensity, mean (SD)	4.6 (2.8)
Severity of PMS, number (%)
No/mild PMS	753 (81.7)
Moderate-to-severe PMS	141 (15.3)
PMDD	28 (3.0)
PMDs	169 (18.3)

Abbreviations: SD, standard deviation; PMS, premenstrual syndrome; PMDD, premenstrual dysphoric disorder; PMDs, premenstrual disorders.

Table 2 Corrected Item-Total Correlation and Cronbach’S α if Item is Deleted for the PSQ and PSQ-S

PSQ	Corrected Item-Total Correlation	Cronbach’s α If Item is Deleted	PSQ-S	Corrected Item-Total Correlation	Cronbach’s α If Item is Deleted
A1	0.765	0.920	A1	0.788	0.921
A2	0.720	0.922	A2	0.735	0.924
A3	0.790	0.920	A3	0.820	0.919
A4	0.775	0.920	A4	0.791	0.920
A5	0.674	0.924	A5	0.680	0.927
A6	0.716	0.922	A6	0.723	0.925
A7	0.773	0.920	A7	0.781	0.921
A8	0.515	0.929	A10	0.713	0.925
A9	0.569	0.927	B1	0.679	0.927
A10	0.739	0.922
A11	0.498	0.929
B1	0.713	0.922
B2	0.571	0.927
B3	0.583	0.927

Notes: A1, depressed mood; A2, anxiety or tension; A3, tearful; A4, anger or irritability; A5, decreased interest; A6, difficulty concentrating; A7, fatigue or lack of energy; A8, overeating or food cravings; A9, insomnia or hypersomnia; A10, feeling overwhelmed; A11, physical symptoms; B1, work efficiency or productivity; B2, social activities; B3, relationships with coworkers or family.

Abbreviations: PSQ, Premenstrual Symptoms Questionnaire; PSQ-S, Premenstrual Symptoms Questionnaire Short-form.

Figure 2 Scree plot for the PSQ-S.

Abbreviation: PSQ-S, Premenstrual Symptoms Questionnaire Short-form.

Table 3 Goodness-of-Fit Summary of the PSQ-S and the PSQ

Model	χ^2 (df)	GFI	AGFI	TLI	CFI	RMSEA (90% CI)	SRMR	AIC
PSQ-S One-factor (9 items + 4 error covariance)	160.5 (23)	0.96	0.93	0.96	0.98	0.08 (0.07–0.09)	0.03	204.5
PSQ One-factor (14 items + 6 error covariance)	424.1 (71)	0.94	0.91	0.94	0.95	0.07 (0.07–0.08)	0.04	492.1

Abbreviations: PSQ-S, Premenstrual Symptoms Questionnaire Short-Form; PSQ, Premenstrual Symptoms Questionnaire; χ², chi-square; df, degrees of freedom; GFI, goodness-of-fit index; AGFI, adjusted GFI; TLI, Tucker–Lewis Index; CFI, comparative fit index; RMSEA, root mean square residual error of approximation; CI, confidence interval; SRMR, standardized root mean square residual; AIC, Akaike’s information criterion.

Figure 3 One-factor model of the PSQ-S (A) and the PSQ (B) and standardized parameter estimates.

Abbreviations: PSQ-S, Premenstrual Symptoms Questionnaire Short-form; PSQ, Premenstrual Symptoms Questionnaire; A1, depressed mood; A2, anxiety or tension; A3, tearful; A4, anger or irritability; A5, decreased interest; A6, difficulty concentrating; A7, fatigue or lack of energy; A8, overeating or food cravings; A9, insomnia or hypersomnia; A10, feeling overwhelmed; A11, physical symptoms such as tender breasts, feeling of bloating, headache, joint or muscle pain, or weight gain; B1, work efficiency or productivity; B2, social activities; B3, relationships with coworkers or family.

Table 4 Correlation Coefficients for the PSQ-S, the PSQ, the PMDD Scale, the SSS-8, and the NRS

	PSQ Total Score Spearman’s r	PMDD Scale Total Score Spearman’s r	SSS-8 Spearman’s r	NRS Spearman’s r
PSQ-S total score	0.978*	0.854*	0.648*	0.437*
PSQ total score	1.000*	0.885*	0.685*	0.445*

Note: *<0.0001.

Abbreviations: PSQ-S, Premenstrual Symptoms Questionnaire Short-form; PSQ, Premenstrual Symptoms Questionnaire; PMDD, premenstrual dysphoric disorder; SSS-8, Somatic Symptom Scale-8; NRS, numerical rating scale.

Table 5 IRT Parameter of the PSQ and the PSQ-S

PSQ	a (SE)	b1 (SE)	b2 (SE)	b3 (SE)	PSQ-S		a (SE)		b1 (SE)	b2 (SE)	b3 (SE)
A1	3.50 (0.17)	−0.01 (0.03)	0.71 (0.04)	1.58 (0.07)	A1		3.65 (0.17)		−0.02 (0.03)	0.70 (0.04)	1.59 (0.07)
A2	2.67 (0.12)	−0.50 (0.04)	0.52 (0.04)	1.75 (0.08)	A2		2.76 (0.13)		−0.50 (0.04)	0.51 (0.04)	1.75 (0.08)
A3	3.89 (0.18)	−0.06 (0.03)	0.66 (0.04)	1.38 (0.06)	A3		4.26 (0.20)		−0.07 (0.03)	0.64 (0.04)	1.37 (0.06)
A4	3.29 (0.15)	−0.52 (0.04)	0.48 (0.03)	1.49 (0.07)	A4		3.45 (0.16)		−0.52 (0.04)	0.46 (0.03)	1.49 (0.07)
A5	2.47 (0.13)	0.22 (0.04)	1.16 (0.06)	2.26 (0.11)	A5		2.42 (0.13)		0.21 (0.04)	1.17 (0.06)	2.30 (0.11)
A6	2.46 (0.12)	−0.40 (0.04)	0.96 (0.05)	2.12 (0.10)	A6		2.38 (0.12)		−0.41 (0.04)	0.97 (0.05)	2.17 (0.10)
A7	3.14 (0.14)	−0.75 (0.04)	0.39 (0.03)	1.43 (0.06)	A7		3.08 (0.14)		−0.75 (0.04)	0.38 (0.03)	1.45 (0.06)
A8	1.28 (0.08)	−0.52 (0.06)	0.72 (0.06)	2.21 (0.10)	A10		2.92 (0.16)		0.39 (0.04)	1.25 (0.06)	2.16 (0.11)
A9	1.48 (0.09)	−0.04 (0.05)	1.04 (0.06)	2.25 (0.10)	B1		2.13 (0.11)		−0.17 (0.04)	1.01 (0.05)	2.28 (0.11)
A10	3.24 (0.17)	0.39 (0.04)	1.22 (0.06)	2.06 (0.10)
A11	1.18 (0.08)	−0.25 (0.06)	1.23 (0.07)	2.91 (0.14)
B1	2.33 (0.12)	−0.16 (0.04)	0.97 (0.05)	2.18 (0.10)
B2	1.96 (0.13)	0.87 (0.06)	1.78 (0.09)	2.89 (0.17)
B3	2.22 (0.15)	0.95 (0.06)	1.91 (0.10)	2.95 (0.18)

Notes: a, discrimination parameter; b1–b3, difficulty parameter; A1, depressed mood; A2, anxiety or tension; A3, tearful; A4, anger or irritability; A5, decreased interest; A6, difficulty concentrating; A7, fatigue or lack of energy; A8, overeating or food cravings; A9, insomnia or hypersomnia; A10, feeling overwhelmed; A11, physical symptoms such as tender breasts, feeling of bloating, headache, joint or muscle pain, or weight gain; B1, work efficiency or productivity; B2, social activities; B3, relationships with coworkers or family.

Abbreviations: IRT, item response theory; PSQ-S, Premenstrual Symptoms Questionnaire Short form; SE, standard error.

Figure 4 Item characteristic curves for the PSQ-S. Theta at the horizontal axis indicates the trait level (severity of premenstrual symptoms). The vertical axis shows the probability for an answer in each of the PSQ-S questionnaire items. Four curves (from 1 to 4) indicate each possible response: curve 1, not at all; curve 2, mild; curve 3, moderate; curve 4, severe. Curve 1, the leftmost curve, shows the probability that each individual would choose 1 out of 4 ratings at different trait levels. The curve shows that the lower the trait level, the higher the probability of choosing 1. Curve 4, the rightmost curve, shows the probability that each individual would choose 4 out of 4 ratings at different trait levels. The curve shows that the higher the trait level, the higher the probability of choosing 4. Curves 2 and 3 between them are unimodal, indicating that at a certain range of trait levels, 2 or 3 is chosen.

Notes: A1, depressed mood; A2, anxiety or tension; A3, tearful; A4, anger or irritability; A5, decreased interest; A6, difficulty concentrating; A7, fatigue or lack of energy; A10, feeling overwhelmed; B1, work efficiency or productivity.

Abbreviation: PSQ-S, Premenstrual Symptoms Questionnaire Short-form.

Figure 5 Item information curves for the PSQ-S. Theta at the horizontal axis indicates the trait level (severity of premenstrual symptoms). The vertical axis shows the amount of information for an answer in each of the PSQ-S questionnaire items. The higher the curve, the greater the amount of information in a narrower range of trait levels and, consequently, the more highly discriminating the item is. On the other hand, items with low discrimination power show a flat curve across a wide range of trait levels, which means that they are less informative.

Notes: A1, depressed mood; A2, anxiety or tension; A3, tearful; A4, anger or irritability; A5, decreased interest; A6, difficulty concentrating; A7, fatigue or lack of energy; A10, feeling overwhelmed; B1, work efficiency or productivity.

Abbreviation: PSQ-S, Premenstrual Symptoms Questionnaire Short-form.

Figure 6 Test information curve and standard error of measurement for the PSQ and PSQ-S. Theta at the horizontal axis indicates the trait level (severity of premenstrual symptoms). The vertical axis shows the amount of summative test information for the PSQ and the PSQ-S.

Abbreviations: PSQ, Premenstrual Symptoms Questionnaire; PSQ-S, Premenstrual Symptoms Questionnaire Short-form; SE, standard error.

Table 6 AUC of the ROC Analysis for the PSQ-S

	AUC	SE	95% CI	Cut Off	Sensitivity/ Specificity	PPV/NPV
PSQ-S	0.960	0.007	0.947/0.973	22	92.3/89.9	67.2/98.1

Abbreviations: AUC, area under the curve; ROC, receiver operating characteristic; PSQ-S, Premenstrual Symptoms Questionnaire Short-form; SE, standard error; CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value.