Introduction
Suicide is a widespread issue of concern worldwide. According to the World Health Organization [
54], suicide was the 18th leading factor of death in the world in 2016, and the second leading factor of death among people aged 15–29. Approximately 800,000 people died of suicide in 2016, with 1 person dying by suicide every 40 s, and even more attempting suicide [
54]. According to the survey of WHO, mortality is expected to increase to one person every 20 s [
54], the issue of suicide has become more serious. Suicide is of increasing concern worldwide, due to its heightened impact on adolescents, as well as the serious impacts it can have on other individuals, families, and societies related to the individual attempting suicide. As previous studies have shown, the incidence of suicide ideation among adolescents was 10.72–12.1% [
24], with suicidal intention and planning at 8.1% [
32]. In China, more than 10,000 teenagers died by suicide each year [
36]. As such, there have been numerous efforts made to improve abilities to identify adolescents at elevated risk of suicide, so as to prevent and effectively reduce the youth suicide rate [
15,
37].
Suicidal behavior is a series of complex processes, from suicidal ideation, suicide plan, suicidal attempt, and suicide death [
19]. Suicidal ideation is the main risk factor for suicidal behavior, refers to the idea that the individual wants to end life [
4]. Although individuals with suicidal ideation do not necessarily died by suicide [
31], suicidal ideation is indeed an important predictor of suicide risk [
18,
22]. Studies have shown that the peak of suicidal ideation occurs in adolescence, with the incidence rising from less than 1% at the age of 10 to 17% at the age of 18 [
32]. In adolescence, adolescents have the cognitive ability to think and evaluate death, but they are in an immature state in terms of cognitive control and emotional response. This imbalance can easily lead to suicidal ideation [
28]. Therefore, paying attention to the related factors of suicidal ideation among adolescents will not only help screen out high-risk groups, but also help maintain the mental health of adolescents [
26].
The development of effective measurement instruments can be an important means for identifying and studying suicidal ideation. A number of instruments have been developed to assess adolescents’ suicide ideation. The Beck scale for suicide ideation (BSI) [
3], which is used to evaluate the status of one’s suicidal ideation over the past week, has 19 items and results in scores in two dimensions, one is suicide ideation and the other is suicidal tendency. The higher the score, the higher one’s risk of suicidal ideation and suicide is. The suicidal ideation questionnaire (SIQ) [
40], consists of 30 items that evaluate specific thoughts and cognitions about suicide and death over the past month. The higher the SIQ score, the more serious one’s suicidal ideation is. The modified scale for suicide ideation (MSSI) [
29] includes 18 items; the higher the score, the more serious one’s suicidal ideation is. Another scale, such as the suicidal ideation scale (SIS) [
42], has been designed for college students, and uses 10 items to measure suicidal ideation over the past year. Although each of these measurements has merits, their limitations cannot be ignored. Most people believe that suicidal behavior is closely related to risk factors, such as psychological distress or psychiatric disorders [
17], and research on suicidal behavior has also focused on the risk factors of suicidal ideation, and rarely considers the protective factors.
It has been noticed, however, the factors affecting suicidal ideation or behavior may be multidimensional [
39]. For example, individuals with suicidal thoughts may also express their desire to survive [
48]. The Positive and Negative Suicide Ideation (PANSI) Inventory combined with risk and protective factors (i.e., positive ideation and negative suicide ideation) to evaluate individual suicidal ideation [
35]. In the original study, the PANSI showed good reliability and a two-factor structure among college students [
35]. The study tested the reliability and validity of the PANSI with diverse samples of young adults, high school students, and psychiatric inpatients, and the results showed good reliability and a stable two-factor structure [
30,
33,
34]. A large number of studies have verified the measurement performance of the scale. For instance, the PANSI has been shown to be an effective and reliable instrument to measure the severity of suicidal ideation among clinical outpatients in Malaysia [
43]. The PANSI has also shown good psychometric properties among Korean middle school students [
23], as well as good reliability and validity among Nigerian college students and Colombian students [
1,
49]. In China, research involving a sample of middle school students and senior high school students in Taiwan found that Cronbach’s alpha coefficients of the PANSI-negative suicide ideation (PANSI-NSI) was .94, and that the PANSI-positive ideation (PANSI-PI) was .86. The two-factor model has also been replicated. However, participants in this study were limited to urban areas [
6]. Another study also found that the PANSI had good reliability and validity among high school students in Henan, China [
50].
Measurement invariance means that, given a latent factor, the conditional distribution of the observed variables is invariant across groups, namely there is no measurement bias associated with a specific group in different conditions [
7]. Studies have shown that when the same measurement scale is applied in different situations, the measurement characteristics are likely to change [
10]. Different groups (e.g., country, gender, and age) may have different understandings of the items in a particular scale [
14,
44,
46]. Although some studies have compared the differences in PANSI scores between genders, the conclusions have been inconsistent. In the PANSI-NSI subscale, males have generally scored significantly higher than females, but there has been no significant difference between the genders in the PANSI-PI subscale [
1]. Some studies have shown that girls’ scores in the PANSI-NSI are significantly higher than those of boys [
6], while others have shown that there is no significant difference between in PANSI scores between males and females [
30,
33,
35]. Single-parent family children refer to children under the age of 18 who are raised by their father or mother alone due to the divorce of their parents or the death of one party, or other reasons, and who do not have the ability to live independently [
5]. Defects in family structure and absence of parent education make children from single-parent families face huge challenges in psychological development and social adaptation [
16,
51], specifically showing more problems in self-esteem, social anxiety, anti-social behavior [
8,
38,
47]. If researchers want to use the PANSI scale to explore the actual differences in suicidal ideation between different groups, it is necessary to ensure that the scale has the invariance of cross-group measurement [
13]. Furthermore, we tested whether the PANSI remained unchanged in the youth age category. In the World Health Organization [
53] age classification, the age of adolescents is 10–19 years. In addition, adolescents are divided into younger adolescents (10–14 years) and older adolescents (15–19 years). Therefore, we divided the age group into 11–14 years and 15–17 years to measure the invariance in the current study. In summary, this study examined the measurement invariance of gender, single-parent and non-single-parent households and age of the PANSI.
Based on the above review of existing literature, this study aimed to evaluate the reliability and validity of the PANSI and its measurement invariance on variables such as gender, single-parent and non-single-parent household and age so as to provide scientific basis for further research in related fields.
Discussion
The PANSI-C is a self-report instrument used to evaluate both the protective factors and negative risk factors associated with suicidal behaviors among adolescents [
35]. The current study examined the psychometric properties of the PANSI-C, especially its measurement invariance, across different samples (i.e., gender, single-parent and non-single-parent households and age). This is the first study to explore the measurement invariance of the PANSI (as the PANSI-C). Our results verify the two-factor structure of the PANSI-C and support the scalar invariance of the PANSI-C in different samples. The results of the current study show that the PANSI-C has good reliability and validity in a sample of Chinese adolescents.
The results of the current study showed that, in terms of reliability, the Cronbach’s alpha coefficients for both the PANSI-NSI and PANSI-PI were acceptable, at .915 and .696, respectively, which is consistent with previous research findings [
34,
35,
43]. Compared with previous studies, the reliability of the PANSI-PI subscale in this study was lower, which may be due to the fact that the participants were normal middle school students and do not understand the positive items of suicidal ideation.
In terms of validity, confirmatory factor analysis fitting indicators were good, indicating that the PANSI-C has good structural validity, which is the same as the structure obtained from the original scale and previous studies [
1,
6,
30,
33‐
35,
43,
49]. It shows that the two-factor structures of the PANSI were also supported in Chinese adolescents. According to correlation analysis, positive ideation was negatively related to negative suicidal ideation and suicide probability, and positively related to and self-esteem. Negative suicidal ideation was negatively related to self-esteem, and positively related to suicide probability, this was consistent with previous studies [
23,
35,
43]. This also verified the good construct validity of the PANSI in China.
Although some studies have compared the differences in the PANSI scores between genders, the conclusions have been inconsistent [
1,
6]. The measurement invariance of a scale should be checked before any comparison of scale scores for different groups is made [
27]. Therefore, we examined the measurement invariance of the PANSI-C between different samples (i.e., gender, single-parent and non-single-parent households and age). We gradually establish four models, namely configural invariance, weak invariance, strong invariance and strict invariance. The results of the configural invariance evaluation show that the number of factors and factor model were equal in gender, single-parent and non-single-parent households samples. The evaluation of weak invariance showed that the scale observation items and potential factors were equivalent in different samples. The evaluation of strong invariance showed cross-group differences in the mean of observed variables reflected the intra-group difference of the mean of potential variables. When strict invariance is obtained, the error variance of each group meets the cross-group equivalent. The results of measurement invariance show that the composition of latent variables, factor loadings, intercept and error variance of the PANSI-C in gender, single-parent and non-single-parent household samples were equal, indicating that the severity of suicidal ideation in different groups can be accurately compared when the PANSI-C is used. In addition, we obtained strong invariance across age groups, indicating that different age groups have the same reference point, so that the latent variable scores estimated by the observed variables are unbiased and the comparison between groups is meaningful. In short, the measurement invariance of the PANSI-C among different samples is obtained. The measurement results of the PANSI-C can be directly compared between different gender, family structure and age groups.
In summary, the PANSI-C consists of two dimensions, positive ideation and negative suicidal ideation, and shows good reliability and validity in the samples used in the current study. It meets the requirements of psychological measurement theory, and is a reliable and effective instrument for detecting the occurrence of suicidal ideation in Chinese adolescents, and can be applied to the psychological assessment of suicidal ideation in Chinese adolescents as well as in other related research fields. Nevertheless, several issues needed to be considered when interpreting these results. First, it lacks popularization to the other samples in China. Future research should be conducted on more representative and larger samples. Second, further studies are needed to explore the measurement invariance of PANSI-C in more groups, for providing evidence for cross-group research.
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