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

Background: Anxiety disorders are among the most common mental health problems in childhood. Early detection and treatment are essential. We aimed to determine the psychometric properties of the Spence Children's Anxiety Scale - parent version (SCAS-P) in children with various psychiatric disorders in Hong Kong.

Methods: Children aged 6 to 12 years and their parents or guardians were recruited by convenience sampling from the child and adolescent psychiatry specialist out-patient clinic at Queen Mary Hospital. The parents or guardians were asked to complete the SCAS-P, the Diagnostic Interview Schedule for Children version IV (DISC-IV) anxiety module, the Screen for Child Anxiety Related Emotional Disorders parent version (SCARED-P), and the Child Behavior Checklist (CBCL).

Results: In total, 135 child-parent pairs were included. The median age of the children (78 male and 57 female) was 10 (range, 8-11) years. The children had various psychiatric diagnoses; 43.7% had attention deficit hyperactivity disorder and 41.4% had autism spectrum disorder. In addition, 57 (42.2%) children were diagnosed by a psychiatrist with at least one anxiety disorder (based on the DISC-IV anxiety module). The median SCAS-P score was 36.0; 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]. The internal consistency of the SCAS-P was high (Cronbach's alpha = 0.938). Convergent validity of the SCAS-P was confirmed with the SCARED-P and CBCL subscales of internalising and anxiety, whereas divergent validity of the SCAS-P was confirmed with the CBCL subscales of externalising, aggression, and delinquency. Test-retest reliability of the SCAS-P was good (intraclass correlation coefficient = 0.90). The SCAS-P had satisfactory criterion validity for any anxiety disorder (area under the curve [AUC] = 0.77), obsessive compulsive disorder (AUC = 0.76), social anxiety disorder (AUC = 0.70), separation anxiety disorder (AUC = 0.81), generalised anxiety disorder (AUC = 0.82), and physical injury fears (AUC = 0.86).

Conclusion: The SCAS-P has satisfactory validity and reliability in screening anxiety disorders among children with various psychiatric disorders. In a busy clinic setting, we recommend using the total SCAS-P score to screen anxiety among children with psychiatric disorders.