Psychometric properties of the Farsi translation of the kiddie schedule for affective disorders and schizophrenia-present and lifetime version

K-SADS-PL is a semi-structured diagnostic interview for children and adolescents aged 6 to 18 years, based on DSM-IV diagnostic criteria [5]. It has essential questions for any diagnosis, which if not met, allow the interviewer to proceed to the next disorder. The symptoms are codified as present or absent. It covers all the most frequent psychiatric disorders in childhood and adolescence including of mood disorders (major depression, and mania), anxiety disorders (separation anxiety, panic disorder, agoraphobia, social phobia, simple phobia, generalized anxiety disorder, obsessive-compulsive disorder, post-traumatic stress disorder), eating disorders (anorexia and bulimia), attention-deficit/hyperactivity disorder (ADHD), conduct disorder and oppositional defiant disorder, elimination disorders (enuresis and encopresis), Tic disorder, psychotic disorders.

The K-SADS-PL was translated by a team of child and adolescent researchers. They had translated the K-SADS-PL into Farsi. The K-SADS-PL-Farsi Version (K-SADS-PL-F) was back-translated by a bilingual child and adolescent psychiatrist. The back-translated version of the KSADS-PL-F was reviewed and reconfirmed by the team and the final translation was fixed by consensus. To examine the feasibility of the K-SADS-PL-F it had been administered to children in a child and adolescent psychiatry clinic. After approval of its performance and establishments of face validity and content validity, it was used in the current study.

The demographic characteristics were asked and then the K-SADS-PL-F was administered to children and their parents by the interviewer (AY), trained in the use of the interview, diagnostic classification and making differential diagnosis. He was a physician who had passed an extensive two-month course of training about K-SADS and psychiatry. Also, in a pilot study he had interviewed with patients under supervision of the child and adolescent psychiatrist. Another interviewer was the trained child and adolescent psychiatrist (AG). The interviewer was unaware of the clinician's diagnosis at the time of making the interview.

Consensual validity or the degree of agreement of diagnosis made by the K-SADS-PL-F interview and clinical child and adolescent psychiatrist interview was studied.

The stability of the translated instrument (K-SADS-PL-F) was tested in the Iranian culture by a test-retest design on 11 subjects who were randomly selected, which all of them were from patients group. They were conducted at four-week intervals. Inter-rater reliability was tested on 14 subjects of patients group who were randomly selected. The two raters interviewed in succession, not in a conjoint session.

The Chi-squared test was used between two interview diagnoses to determine the sensitivity, specifity, positive predictive validity, negative predictive validity, and the degree of agreement between the two interviews.

The concordance analysis of diagnoses generated by the clinician and the K-SADS-PL-F administrator was done by the kappa coefficient (κ).

The frequency of psychiatric disorders made by the child and adolescent psychiatrist were; ADHD, 57.8%; oppositional defiant disorder, 50.5%; conduct disorder, 22.9%; Tic disorder, 9.2%; bipolar mood disorders, 17.4%; major depressive disorder, 6.4%; separation anxiety disorder, 19.2%; panic disorder, 1.8%; social phobia, 11.0%; simple phobia, 18.3%; generalized anxiety disorder, 17.4%; obsessive-compulsive disorder, 9.2%; post-traumatic stress disorder, 9.2%; anorexia nervosa, 0.9%; enuresis, 15.6%; encopresis, 0.9%.

The consensual validity of diagnosis by the K-SADS-PL-F is shown on Table 1. Panic disorder, conduct disorder, Simple Phobia, and ADHD had the highest kappa score for consensual validity.

Test-retest reliability of the K-SADS-PL-F diagnosis is shown in Table 2, and Table 3 shows the inter-rater reliability of diagnosis. Sensitivity, specifity, positive predictive validity, negative predictive validity of the K-SADS-PL-F are indicated in Table 4. The highest positive predictive validity was for tic disorder, panic disorder, and post traumatic disorder. The lowest positive predictive values were for anorexia nervosa, encopresis, and separation anxiety disorder. Negative predictive validity was very high for all of the disorders.