East Asian Arch Psychiatry 2024;34:51-57 | https://doi.org/10.12809/eaap2425

ORIGINAL ARTICLE

Validity and reliability of the Spence Children’s Anxiety Scale – parent version among Hong Kong children with various psychiatric disorders

HK Cheung, YC Tang, HS Yu

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HK Cheung, Department of Psychiatry, Queen Mary Hospital, Hong Kong SAR, China
YC Tang, Department of Psychiatry, Queen Mary Hospital, Hong Kong SAR, China
HS Yu, Department of Psychiatry, Queen Mary Hospital, Hong Kong SAR, China

Address for correspondence: Dr Cheung Hoi Ki, Room 305, Printing House, 6 Duddell Street, Hong Kong SAR, China. Email: elkicheung@fellow.hkam.hk

Submitted: 13 May 2024; Accepted: 29 July 2024

Introduction

Anxiety is characterised by fear or worries arising from the anticipation of real or imaginary threats. Anxiety disorders are among the most common mental health problems in childhood.¹ In a meta-analysis of studies involving 63 130 children and adolescents, the prevalence of anxiety disorder is 6.5%.1 In Hong Kong, the prevalence is 6.9% among children aged 12 to 15 years.² Anxiety, when associated with functional impairment, may affect social and academic development; early treatment is essential.^3,4

The diagnosis of anxiety should be made by a psychiatrist using a structured, evidence-based clinical interview, such as the anxiety module of the Diagnostic Interview Schedule for Children version IV or 5 (DISC- IV or DISC-5). Nonetheless, questionnaires in the form of rating scales, such as the Spence Children’s Anxiety Scale – parent version (SCAS-P), are valuable screening tools.

The manifestations of anxiety differ between clinical and community settings.^4-8 To date, no questionnaire for anxiety has been validated for use in clinical samples in Hong Kong. The psychometric properties of the SCAS-P vary across cultures, and thus there is a need for a local validation study.^9,10 Cultural differences in SCAS-P scores and the questionnaire’s psychometric structure are attributed to socio-economic status, parenting habit, academic atmosphere, and self-disclosure, or lack thereof, of emotional states.¹¹ In particular, academic pressure correlates with anxiety symptoms in Hong Kong children.¹⁰ Most studies to date have included either community samples or patients in whom anxiety was the major, or even exclusive, diagnosis.^7,8,11-16 We aimed to determine the psychometric properties of SCAS-P in children with various psychiatric disorders.

Methods

Children aged 6 to 12 years who attended the child and adolescent psychiatry specialist out-patient clinic at Queen Mary Hospital, together with their parents or guardians who could communicate in Chinese, were recruited between October 2021 and January 2022 using convenience sampling. Children were excluded if they had psychosis, severe medical illness, or learning disability. The parents or guardians were asked to complete the SCAS-P, the parent version of the DISC-IV anxiety module, the Screen for Child Anxiety Related Emotional Disorders – parent version (SCARED-P), and the Child Behavior Checklist (CBCL).

The SCAS-P contains 38 items in six dimensions, namely separation anxiety disorder, social anxiety disorder, obsessive compulsive disorder (OCD), panic disorder and agoraphobia, generalised anxiety disorder, and physical injury fears. Parents are asked to rate the frequency of various symptoms or behaviours using a four-point scale from 0 (never) to 3 (always). The SCAS-P has been validated and has satisfactory diagnostic performance in clinical and community populations worldwide.^{5-8,11-14,17-22} It has good internal consistency and a six-factor structure among neurotypical children.^{6,8,11,13,19,23-25} In Hong Kong, the Chinese version of the SCAS-P has been validated in 207 children in community and found to have a six-factor structure, good internal consistency and convergent validity, but test-retest reliability and criterion and divergent validity were not assessed.6 The original validation study of the Chinese version of SCAS-P, conducted in mainland China, found high internal consistency (Cronbach’s alpha was 0.90 among fathers and 0.91 among mothers) and satisfactory test-retest reliability (0.66 among fathers and 0.72 among mothers).19 The subscales also showed acceptable internal consistency (Cronbach’s alpha = 0.64-0.74) and test- retest reliability (0.46-0.70). The correlations between the SCAS-P and the internalising subscale of the CBCL were higher than those between the SCAS-P and the externalising subscale of the CBCL (0.58 vs 0.42 among fathers and 0.56 vs 0.38 among mothers (both p < 0.01). These support the convergent and divergent validity of the SCAS-P in mainland China. The discriminant validity of the SCAS-P was verified by significant differences in SCAS-P scores between the community and clinical samples.

The parent version of the DISC-IV anxiety module was used because (1) the youth version has poor test-retest reliability²⁶; (2) most studies on childhood anxiety use the parent version²⁷; and (3) parents are reliable informants, whereas children are less consistent in reporting anxiety and depressive symptoms.²⁸

The 41-item SCARED-P was used to match the subscales in the SCAS-P, whereas the CBCL was used to assess emotional and behavioural problems in children. The CBCL has been used to validate both the SCAS and SCAS-P.^20,25

Internal consistency of the SCAS-P was assessed; Cronbach’s alphas of 0.7 to 0.8 was considered good. Convergent validity of the SCAS-P was assessed by measuring the Spearman correlations between the SCAS-P and the SCARED-P as well as the internalising and anxiety subscales of the CBCL, whereas divergent validity of the SCAS-P was assessed by measuring the Spearman correlations between the SCAS-P and the externalising, aggression, and delinquency subscales of the CBCL. An ideal instrument should have high correlations with instruments that measure similar constructs (convergent validity) and low correlations with instruments that measure unrelated constructs (divergent validity). Criterion validity was assessed using the DISC-IV anxiety module as the diagnostic benchmark. The area under the receiver operating characteristic curve (AUC) was calculated to determine the diagnostic sensitivity and specificity of the SCAS-P and optimal cut-off scores; an AUC of 0.8 to 0.9 was considered good diagnostic performance. Cut-off scores were selected based on their Youden’s indices to achieve a balance between sensitivity and specificity. Test-retest reliability was assessed by re-administering the SCAS-P in a random sample of participants after 2 to 4 weeks. An intraclass correlation coefficient of 0.8 to 0.9 was considered good test-retest reliability.

Sample size estimation was based on a Swedish study, in which the effect size, as measured by Cohen’s d, of the mean SCAS-P score difference between anxiety and non- anxiety groups ranged from 0.69 to 1.43.5 To detect an effect size of 0.6 with 80% power and a two-tailed significance level of 0.05, 20 participants were needed for each of the six subscales of the SCAS-P. Hence, the total number of participants needed was 120. This number is comparable to that from other studies.^5,13 Statistical analyses were performed using SPSS (Windows version 25.0; IBM Corp, Armonk [NY], United States). Comparisons were made using Mann-Whitney U or Chi-squared tests. All tests were two-tailed. A p value of <0.05 was considered statistically significant. There were no missing data.

Results

Of the 152 child-parent pairs invited, 135 (88.8%) consented to participate. Most parent respondents were mothers (n = 115), followed by fathers (n = 15), both parents (n = 3), and aunts (n = 2). The median age of the children (78 male and 57 female) was 10 (interquartile range, 8-11) years. The children had various psychiatric diagnoses, namely attention deficit hyperactivity disorder (ADHD) [n = 59], autism spectrum disorder (ASD) [n = 56], features of oppositional defiant disorder (n = 42), tics / Tourette syndrome / impulse control disorders (n = 16), affective disorders (n = 3), and sibling rivalry (n = 2). In addition, 57 (42.2%) children were diagnosed by a psychiatrist with at least one anxiety disorder (based on the DISC-IV anxiety module), namely social anxiety disorder (n = 32), separation anxiety disorder (n = 23), specific phobia (n = 31), panic disorder (n = 2), agoraphobia (n = 2), generalised anxiety disorder (n = 14), and OCD (n = 12).

The median SCAS-P score was 36.0 (interquartile range, 23.0-51.0); it was higher in children with anxiety disorder (n = 57) than in children without anxiety disorder (n = 78) [46.0 vs 28.5, p < 0.001]. Sex, age, and family characteristics were not associated with SCAS-P scores or the presence of an anxiety diagnosis, but the presence of anxiety disorders was more common in children without ADHD than in children with ADHD (50.3% vs 30.5%, p = 0.022, Table 1). Children with ASD (n = 56) and children without ASD (n = 79) were comparable in terms of total SCAS-P score (36 vs 38, p = 0.617) and subscale scores, as well as the presence of at least one anxiety disorder (50% vs 36.7%, p = 0.157).

The SCAS-P had high internal consistency (Cronbach’s alpha = 0.938, 95% confidence interval [CI] = 0.922-0.952). Convergent validity of the SCAS-P was confirmed by strong correlations with the SCARED-P and its subscales as well as the CBCL subscales of internalising and anxiety, whereas divergent validity the SCAS-P was confirmed by weak correlations with the CBCL subscales of externalising, aggression, and delinquency (Table 2).

In the receiver operating characteristic analysis, SCAS-P total and subscale scores had satisfactory diagnostic performance with regard to DISC-IV diagnoses. The optimal cut-off scores of the SCAS-P for diagnosing various anxiety disorders are shown in Table 3; the specificities ranged from 0.43 to 0.68 and the sensitivities ranged from 0.81 to 0.99. The SCAS-P had satisfactory criterion validity in terms of any anxiety disorder (AUC = 0.77, 95% CI = 0.63-0.80), OCD (AUC = 0.76, 95% CI = 0.66-0.85), social anxiety disorder (AUC = 0.70, 95% CI = 0.61-0.80), separation anxiety disorder (AUC = 0.81, 95% CI = 0.73-0.89), generalised anxiety disorder (AUC = 0.82, 95% CI = 0.72-0.93), and physical injury fears (AUC = 0.86, 95% CI = 0.80-0.92).

The correlations between SCAS-P subscales were highest between generalised anxiety disorder and panic disorder subscales (Spearman’s rho = 0.755) and lowest between physical injury fears and OCD subscales (Spearman’s rho = 0.407). The physical injury fears subscale had weak-to-moderate correlations with other subscales, whereas the generalised anxiety disorder subscale had moderate-to-strong correlations with other subscales and the overall scale (Table 4).

Test-retest reliability among 45 participants was good for SCAS-P total score (intraclass correlation coefficient = 0.90, 95% CI = 0.81-0.94) and subscale scores (intraclass correlation coefficients = 0.74-0.91).

Of the five most-reported anxiety symptoms, three were in the social anxiety disorder subscale (item 9: “My child feels afraid that (s)he will make a fool of him/herself in front of people”, item 26: “My child worries what other people think of him/her”, and item 31: “My child feels afraid when (s)he has to talk in front of the class”), one was in the physical injury fears subscale (item 2: “My child is scared of the dark”), and one was in the generalised anxiety disorder subscale (item 1: “My child worries about things”), whereas the five least-reported anxiety symptoms were in the panic disorder subscale (item 30: “My child complains of suddenly becoming dizzy or faint when there is no reason for this”, item 25: “My child feels scared if (s)he has to travel in the car, or on a bus or train”, item 32: “My child complains of his/her heart suddenly starting to beat too quickly for no reason”, item 19: “My child suddenly starts o tremble or shake when there is no reason for this”, and item 12: “My child complains of suddenly feeling as if (s) he can’t breathe when there is no reason for this”).

Discussion

Among children in Hong Kong with various psychiatric disorders, the prevalence of anxiety disorder was 42.2%, which is comparable to the 52.9% reported in a Swedish study.⁵ The median SCAS-P score was 36.0, which is comparable to the 31.0 to 42.8 reported in other studies.^{5,7,11,14,18,19,21,24} Internal consistency between the SCAS-P total and subscale scores was 0.938, which is comparable to the 0.87 to 0.90 reported in other studies, whereas the physical injury fears subscale was least correlated with other subscales (Spearman’s rho = 0.407- 0.594), which is lower than the 0.49 to 0.74 reported in other studies.^{5-8,11,14,17,19-22,25} One possible explanation is that children who have one specific fear may not necessarily have other fears. The individual items of the physical injury fears subscale may be unable to capture the wide range of fears experienced by children,8,11,20 for example, horror movie scenes, nightmares, ghosts/monsters, needles, poor academic results, and thunder and loud noises. According to the DSM-IV, there are five categories of specific phobias, namely fear of natural phenomena such as height, storms, and water (the latter two are not included in SCAS-P), fear of animals (only insects and dogs are included in SCAS-P), blood-injection fear (not specifically included in SCAS-P), and fear of specific situations such as enclosed spaces (which is included in the panic disorder subscale [item 34], rather than the physical injury fears subscale). These deviances from the DSM-IV may explain the lower internal consistency of the physical injury fears subscale. Future studies should include local specific items to refine the physical injury fears subscale.

The SCAS-P had good convergent validity with the SCARED-P and the internalising and anxiety subscales of the CBCL, in keeping with the literature that suggests a close association between anxiety and depression symptoms.^3,19,20,29 Its divergent validity was confirmed by weak correlations with CBCL subscales of externalising, aggression, and delinquency, consistent with previous studies.^19,20 For criterion validity, diagnostic performance was satisfactory (AUC >0.7) for the total and subscale scores, consistent with other studies.^5,17 Test-retest reliability was good (>0.90 for all subscales except for the generalised anxiety disorder subscale [0.85] and OCD subscale [0.74]) and superior to the 0.60 to 0.87 reported in a previous study.¹¹

Three of the five most-reported anxiety symptoms were under the social anxiety disorder subscale. The elevated social-evaluative fears may be due to more emphasis on obedience, self-control, emotional restraint, and compliance to social rules in Chinese cultures.^10,30 This is understandable, given that child-rearing practices among Chinese people are generally restrictive and influenced by the opinions of others.³⁰ In Hong Kong, general performance and subsequent reward are correlated with anxiety symptoms.¹⁰ On the contrary, school performance (ie, item 6: “My child is scared when s(he) has to take a test” and item 10: “My child worries that (s)he will do badly at school”) were not among the most-reported anxiety symptoms in the present study. One possible explanation is that the study period coincided with the peak of the COVID-19 pandemic, during which most schools adopted virtual teaching and examinations were suspended. Interestingly, no items from the separation anxiety disorder subscale were among the most reported. This may be because the exact meaning of some items might be influenced by parental beliefs and parenting styles. Items such as “My child gets scared if he/ she sleeps away from home” and “My child worries about sleeping alone” are meant to measure separation anxiety in Western societies but might be considered normal in Chinese cultures because Chinese mothers are expected to devote themselves wholeheartedly to their children.³¹ In other words, children in Hong Kong are expected to spend a great deal of time with their parents, so items related to manifestations of separation anxiety in Western cultures might be regarded as normal in Hong Kong.

Compared with children without ASD, children with ASD tended to have higher rates of separation anxiety disorder (25.0% vs 11.4%, p = 0.061) and OCD (14.3% vs 5.1%, p = 0.074). In fact, patients with ASD tend to have higher rates of anxiety (ranging from 11% to 84%).³² At least 30% to 50% of individuals with ASD are diagnosed with anxiety disorders, and children with ASD can experience intense anxiety when prevented from engaging in their routines.^22,24,32 The lack of significant difference in anxiety levels between our children with and without ASD might be due to the fact that ASD symptoms can mimic those of other common psychiatric disorders and confound the diagnosis of anxiety.³³ For example, the ritualistic and stereotypic behaviours of ASD (eg, echolalia, rocking) might be interpreted as manifestations of anxiety but are not captured by the SCAS-P.^22,24 Repetitive behaviours could be misinterpreted as OCD and the avoidance of social situations as social anxiety disorder.²⁴

Compared with children in the community, children with ADHD have higher prevalence of anxiety disorders (27.5% vs 6.9%).³⁴ However, in the present study, the prevalence was lower among children with ADHD than among children without ADHD (30.5% vs 50.3%). This might be explained by the fact that our sample included children with a mix of psychiatric disorders, such that those without ADHD may have other disorders, such as anxiety or ASD, which may make them more prone to anxiety.^22,24,30Our sample size was not large enough for subgroup analyses; therefore, the application of SCAS-P to children with ASD or ADHD should be taken with caution.

The SCAS-P is based on the DSM-IV anxiety disorder module. The SCAS-P items addressing OCD are therefore not consistent with DSM-5, in which OCD is no longer classified as an anxiety disorder. Also, no SCAS-P items specifically address the newly defined anxiety disorder of selective mutism. Nevertheless, the differences between DSM-IV and DSM-5 are minor and do not alter the relatability of other SCAS-P subscales. Future studies may investigate the use of the SCAS-P to detect selective mutism, as some of the social anxiety disorder items are associated with this anxiety disorder.17 There are changes in the DISC-5 anxiety module, namely that specific settings in which anxiety symptoms occur are elaborated and that more situations are described for specific phobias. For agoraphobia, the definition of large open spaces is added. Both OCD and posttraumatic stress disorder remain within the anxiety module. These changes parallel those in the DSM-5. Therefore, changes from DISC-IV to DISC-5 would have no major effect on our study. Moreover, most studies to date were based on the DISC-IV rather than the DISC-5. At the time of our study, the Cantonese version of the DISC-IV was freely available and therefore adopted.

The present study has several limitations. Our sample was restricted to children with various psychiatric disorders in a single centre and hence the findings cannot be generalised to other populations in the community. However, the response rate was high and there were no missing data, and the anxiety diagnosis was made by a psychiatrist based on the DISC-IV anxiety module.

Conclusion

The SCAS-P has satisfactory validity and reliability in screening anxiety disorders among children with various psychiatric disorders. We recommend using the total SCAS-P score to screen anxiety among children with psychiatric disorders in view of its favourable sensitivity. The SCAS-P is easy to use in a busy clinic setting, in which sensitivity rather than specificity is preferred.

Contributors

All authors designed the study, acquired the data, analysed the data, drafted the manuscript, and critically revised the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

Conflicts of interest

All authors have disclosed no conflicts of interest.

Funding/support

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Data availability

All data generated or analysed during the present study are available from the corresponding author on reasonable request.

Ethics approval

This study was approved by Institutional Review Board of The University of Hong Kong / Hospital Authority

Hong Kong West Cluster (reference: UW 21-512). The participants provided written informed consent for all treatments and procedures and for publication.

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