Introduction
Within the field of psychiatry, the definition of a mental disorder implies significant distress or disability in social, occupational and/or other activities (1). However, many adolescents have multiple mild symptoms, or fewer severe symptoms, and do not meet the criteria for a mental disorder. Therefore, it is crucial to also consider the level of distress and disability in adolescents with psychiatric symptoms. Impairment can be measured in terms of the level of function (2-5). To assess this level, it is important to determine the capacity to perform a task in different settings (2-4).
The International Classification of Impairments, Disabilities, and Handicaps was developed in the 1970s. Using such a classification, the consequence of disabilities may be better assessed within a given physical and social environment. Some diagnostic instruments lack clarity in how to assess domains of functioning. For example, Angold et al. (6) indicated that a condition may be considered to be subthreshold according to the intensity of symptoms but can still cause low functioning (6-9). There is also a need to improve the measures of adolescent functioning and to develop psychometrically sound instruments. In psychiatric patients, disability is associated with the severity of specific symptoms, the number of different symptoms and the number of comorbid diagnoses (10, 11). The reduction of symptoms corresponds to an improvement in occupational and social functioning (12). It has been suggested that each diagnosis has its own pattern of disability (13, 14). For instance, major depressive disorder (MDD) is associated with low physical, cognitive and social functioning (15-17), social anxiety disorder (SAD) is associated with absence from school, isolation and social impairment (7), and attention-deficit/hyperactivity disorder (ADHD) decreases the ability to sustain attention and negatively influences school achievement, peer relationships and adjustment in the family (7, 18, 19). However, multiple factors beyond a diagnosis are related to the level of disability. These include the child’s intellectual development, the characteristics of the school and peers, and several lifestyle factors (20-22).
Previous research on functioning in adolescents has considered it in different settings: at school, with peers and at home in the family (20). One instrument used to assess functioning in adults is the Sheehan Disability Scale (SDS) (8). Moreover, Hörberg et al. have indicated that the correlation between the self-reported SDS score and the expert-rated Global Assessment of Functioning (GAF) score in a sample of adult patients was (r = – .606) (23).The SDS measures function in terms of impairment at work/school and in social and family life in adults with mental illness, and it is sensitive to change during treatment (14, 23-25). Whiteside (9) developed the Child Sheehan Disability Scale for self-report (CSDS) and parent report (CSDS-P) for use among children and adolescents (5–19 years) with anxiety. The CSDS estimates impairment in educational, social and family domains and has similar psychometric properties to those of the adult SDS.
To our knowledge, Whiteside (9) has published the only study to have applied the CSDS in child populations (one clinical and one community sample). Whiteside examined the inter-item correlation separately for the child and parent scales, and, because of the redundancy, the child’s ability to function in the family item was replaced by the parent’s ability to function in the family item in the parent scale. Thereafter, the principal component analysis of the CSDS-P found that a one-factor solution explained the variance in the parent scale.
Objective
The objective of this study was to evaluate the psychometric properties of the Swedish CSDS and CSDS-P in a sample of adolescent psychiatric patients and their parents.
Methods
Study design
This psychometric study explored the reliability and validity of the Swedish versions of the CSDS and CSDS-P in an adolescent psychiatric sample. Reliability was assessed by exploring internal consistency and factor structure. The sensitivity and specificity, and appropriate cut-offs of CSDS and CSDS-P to identify patients with at least one diagnosis versus those without a diagnosis, were tested. A functional impairment is a prerequisite for just about every diagnosis in psychiatry. Therefore, any diagnosis versus no diagnosis was chosen as the outcome. Sensitivity (to detect a diagnosis) was set to at least 80%, while specificity (to detect those without a diagnosis) was set to at least 50%.
To investigate concurrent validity, the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL) and the Strengths and Difficulties Questionnaire (SDQ) were used for comparisons (8, 9, 26-29). Spearman’s rho correlations were used to calculate the concurrent validity of the total score of CSDS/CSDS-P and K-SADS. Moreover, the correlations between the total scores for CSDS and CSDS-P were analyzed, as well as the correlations between the items for “school” and “friends” from the two scales.
Participants
The participants were recruited from an ongoing cohort study of adolescents seeking help for psychiatric problems. Recruitment was performed between September 2011 and June 2013. All new psychiatric outpatients aged 12–17 years (N = 202) and their parents from two clinics in the County of Västmanland, Sweden, were invited to participate. Exclusion criteria were non-Swedish-speaking adolescent/parents or need of in-patient care at the time of the K-SADS-PL interview. A total of 125 (61.9%) patients participated, n = 53 (42.4%) male.
Of these, 107 adolescents provided full information on the K-SADS and CSDS, and 104 provided full information on the SDQ, while their parents completed the CSDS-P (n = 107) and SDQ (n = 104) using the Electronic Psychiatric Intake Questionnaire (EPIQ) (30) (Figure 1).
FIGURE. 1.
Flow chart of the eligible population, external and internal drop-out, and patients with complete information to the analyses
The remaining 18 patients were excluded from the study because of a lack of information. Internal drop-out analysis showed no significant difference in age or sex between those who completed the study (n = 107, 42% male, mean age 15.7 [SD 1.5] years) and those who did not (n = 18, 44.4% male, mean age 15.7 [SD 1.5] years).
Ethical aspects
The study was conducted in accordance with the Declaration of Helsinki (31) and approved by the Regional Ethics Committee of Uppsala (Dnr 2008/214).
Procedure
At the first visit to the clinic, verbal information about the study was given, and informed consent was collected from participants. The adolescents answered the electronic psychiatric intake questionnaire (EPIQ), and parents answered the EPIQ-Parent version. Both versions include the SDQ. At the second visit, within one week, the adolescents and parents were interviewed with the K-SADS-PL. Thereafter, the adolescents and parents reported on the CSDS and the CSDS-P, respectively.
Interviewer training
The interviewers were trained to perform the K-SADS interviews. The inter-rater reliability (IRR) was good to excellent, both before and during the period of data collection. The IRR rate was calculated for each diagnosis and each interviewer, and mean IRRs were calculated for the group and all diagnoses. Overall kappa for the group was .84 (range .54–1.00). Mean kappa was .89 for depression disorders, .79 for ADHD, and varied from .64 to 1.00 for anxiety disorders, as reported previously (32).
Measures
The CSDS and CSDS-P have been translated into Swedish. The original CSDS by Whiteside assesses general functioning in relation to “fears and worries” (9). In the Swedish version, this was changed to general functioning in relation to “troubles and feelings”. Three independent experts did the translation and back-translation for proper language adaptation and finally, the authors of this study approved the final translation.
For layout, see the Swedish CSDS and Swedish CSDS-P in Swedish and English in the Appendix.
The Swedish Child Sheehan Disability Scale (Swedish CSDS). The Swedish CSDS measures general functioning, in relation to “troubles and feelings”. It includes three items about functioning at school, with friends and at home. The questions are “How much do troubles and feelings cause problems for you when you are in school and when you do homework?”, “How much do troubles and feelings cause problems for you when you are with your friends?” and “How much do troubles and feelings cause problems for you when you are at home?”. The score of each item ranges from 0 (“not at all”) to 10 (“very, very much”), resulting in a total scale range of 0–30.
To define patients with low functioning, Leon et al. suggested a cut-off score of 5 for the SDS in adult primary care populations (25). In addition, Sheehan et al. proposed cut-off scores of ≤1 on each item of the SDS and <5 on the total score as remission criteria (14). By contrast, Whiteside studied the CSDS and the CSDS-P in two samples with a primary anxiety disorder and analysed the mean values of the most common anxiety diagnoses and the effect of the treatment without reference to a remission cut-off (9). Based on the SDS studies, a cut-off of 5 was chosen to define functional impairment on the CSDS (14, 25)
The Swedish Child Sheehan Disability Scale-Parent Report (Swedish CSDS-P). The Swedish CSDS-P (parent version) is analogous to the Swedish CSDS (child version) and has three items that assess the level of interference with the parent’s functioning at work and in social and family life: “The symptoms have disrupted your work”, “The symptoms have disrupted your social life” and “The symptoms have disrupted your family life/home responsibilities”. The CSDS-P also contains an additional two items concerning the impact on the child: “The symptoms have disrupted your child’s schooling” and “The symptoms have disrupted your child’s social life”. The score of each item ranges from 0 (“not at all”) to 10 (“very, very much”), resulting in a total scale range of 0–50. In Whiteside’s study (9), the CSDS-P total mean (M) and standard deviation (SD) were M = 22.7 (SD = 11.9) for children with anxiety diagnoses and M = 2.89 (SD = 5.5) for the community controls.
Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL). The K-SADS-PL is a semi-structured diagnostic interview that integrates information from children, parents and the clinical judgement of the interviewer (26, 27). The K-SADS-PL consists of a screening interview and eight supplements for 23 diagnostic domains (26). It has excellent IRR and test–retest reliability supporting its ability to generate valid child psychiatric diagnoses (26, 27, 33, 34). In the K-SADS-PL, comorbidity is presented as the number of specific diagnoses. The K-SADS diagnoses are grouped as follows: any depression (Major Depression, Major Depression with Psychotic Features*), any anxiety (Separation Anxiety, Specific Phobia, Social Anxiety Disorder, Panic Disorder, Agoraphobia, Generalized Anxiety, Obsessive-Compulsive Disorder, Post-traumatic Stress Disorder and Acute Stress Disorder) and any ADHD (ADHD combined, predominantly inattentive, predominantly hyperactive/impulsive and unspecified). At the time of the assessment, the only patient with bipolar diagnosis presented a manic episode. Moreover, a general K-SADS-PL symptom summation index was calculated by adding up the obtained scores during the screening interview and supplements, in a way analogous to that used by Sonnby et al. and Olofsdotter et al. in their previous studies (32, 35). The different ranges for symptom summation indexes were as follows: depression (0–114), manic episode (0–52), psychotic disorder (0–103), panic disorder (0–56), agoraphobia (0–6), separation anxiety disorder (0–27), social anxiety disorder (0–9), specific phobia (0–56), generalized anxiety disorder (0–35), obsessive-compulsive disorder (OCD; 0–98), enuresis (0–9), encopresis (0–9), anorexia nervosa (0–12), bulimia nervosa (0–30), ADHD (0–57), oppositional defiant disorder (0–24), conduct disorder (0–45), tic disorders (0–56), autism (0–43), tobacco use disorder (0–14), alcohol use disorders (0–514), drug use disorder (0–53) and post-traumatic stress disorder (0–66). Scores range from 0 to 2 or 0 to 3 for each symptom depending on the item, and the total range is 0–1488.
Furthermore, the total K-SADS function summation index was calculated by adding the obtained scores of summations of function questions of each specific diagnosis. Ranges were as follows: depression (0–6), manic episode (0–10), psychotic disorder (0–8), panic disorder (0–6), separation anxiety disorder (0–6), social anxiety disorder (0–6), specific phobia (0–6), generalized anxiety disorder (0–6), OCD (0–16), ADHD (0–6), oppositional defiant disorder (0–6), conduct disorder (0–6), tic disorders (0–6), autism (0–6) and post-traumatic stress disorder (0–8). Each function question has a score range from 0 to 2, and the total K-SADS function summation index is 0–108.
Strengths and Difficulties Questionnaire (SDQ)–self-report and parent versions. The SDQ is a brief behavioural screening questionnaire (29). There are equivalent versions for adolescents and parents/teachers (28, 29). Goodman developed the SDQ based on the brief Rutter questionnaires and the Child Behaviour Checklist (28, 29, 36, 37). The Swedish translation of the SDQ parent version has been evaluated with the parents of children aged 6–10 years and deemed to be a reliable and valid measure (29, 38). Adolescent self-reports in Nordic populations show similar distributions of SDQ scores, and in a study of adolescent self-reports, the emotional subscale of the SDQ showed usefulness in differentiating depressed from non-depressed cases (39, 40).
The SDQ consists of 25 items grouped on five subscales, each with five items, with each item using a three-point Likert scale (0 = not true, 1 = somewhat true and 2 = certainly true) (28). The subscales produce scores for emotional symptoms, conduct problems, hyperactivity-inattention, peer problems and prosocial behavior. Some items are reverse scored, and prosocial behavior is considered protective.
Statistical analysis
The chi-square test was used to compare sex and the Mann–Whitney U test was used to compare age between internal drop-outs and participants with complete interviews and forms.
A principal component analysis with varimax rotation was used to evaluate the psychometric properties. Internal consistency was assessed with Cronbach’s alpha (expected > .7) (41, 42).
Following Leon et al. (25), the SDS cut-off of 5 was used to define patients with low functioning. Because of the inherent definition of functional impairment related to the determination of any diagnosis, the sensitivity and specificity of the CSDS/CSDS-P for at least one diagnosis were taken into account (42). When at least one diagnosis was confirmed indicating low functioning, the optimal cut-offs for CSDS or CSDS-P were considered if the sensitivities were above 80% and the specificities were not below 50% (43)
Spearman’s rho was used to calculate all correlations, including those between a) the CSDS/CSDS-P and K-SADS-PL symptom summation index, b) the CSDS/CSDS-P and the total K-SADS function summation index, c) the CSDS/CSDS-P and the K-SADS function summation index of each diagnosis, d) the CSDS/CSDS-P and SDQ adolescents/SDQ parents, respectively, and between the CSDS/CSDS-P and the number of diagnoses.
In addition, this was used to calculate the correlations between the total scores of the CSDS and the CSDS-P, between the first items of both scales (“school” and “child’s school”) and between the second items of both scales (“friends” and “child’s friends”).
Spearman’s rho correlations were classified as very high (.90–1), high (.70–.90), moderate (.50–.70), low (.30–.50) and negligible (0–.30) (44). IBM SPSS Statistics for Windows (Armonk, NY, USA), version 24.0, was used for the statistical analyses.
Results
Descriptive data of the study group
There was no significant age difference between the internal drop-out group and the study group (U = 947, p = .910), and no significant sex difference (χ2 = .036, p = .850). There was no significant age difference between males and females (U = 1202, p = .223). The most frequent diagnoses in the study sample were ADHD (55.1%), MDD (42.1%) and SAD (31%) (Table 1). Diagnoses were grouped into any depression (one patient with bipolar diagnosis, who presented a manic episode at the time of the interview, was not included in depression group), any anxiety, any ADHD or any other diagnoses (Table 1). Seven patients (6.5%) did not fulfil criteria for any diagnosis.
TABLE 1.
Descriptive data of the participants
| Participants | Total n = 107 | Male n = 45 | Female n = 62 |
| Mean age (SD) | 15.7 (1.5) | 15.5 (1.5) | 15.9 (1.4) |
| Mean number of disorders (SD) | 2.6 (2.1 | 1.8 (1.2) | 3.1 (2.1) |
| Groups of K-SADS diagnoses | Number (%) | Number (%) | Number (%) |
| ADHD | 59 (55.1) | 31 (68.9) | 28 (45.2) |
| Anxiety | 58 (54.2) | 12 (11.2) | 46 (74.2) |
| Depression | 45 (42.0) | 14 (31.1) | 31 (50) |
| Any other diagnosis | 5 (4.6) | 2 (4.4) | 3 (4.8) |
| Without any diagnosis | 7 (6.5) | 5 (11.1) | 2 (3.2) |
| SDQ | Adolescent | Parent | |
| Mean score (SD) | Mean score (SD) | ||
| Total difficulties score (range 0–40) | 16.9 (5.6) | 16.6 (5.4) | |
| Subscale scores (range 0–10) | |||
| Emotional problems | 5.1 (2.8) | 5 (2.4) | |
| Conduct problems | 2.8 (1.6) | 2.8 (1.0) | |
| Hyperactivity | 6.2 (2.3) | 5.8 (2.8) | |
| Peer problems | 2.9 (1.0) | 3.1 (2.0) | |
| Prosocial* | 7.5 (2.1) | 7.1 (2.1) | |
| CSDS (range 0–30) | Mean score (SD) | CSDS-P (range 0–50) | Mean score (SD) |
| School | 5.2 (3.0) | Child’s school | 7.2 (2.7) |
| Friends | 3.5 (2.1) | Child’s friends | 5.5 (2.7) |
| Home | 4.2 (3.0) | ||
| Parent’s work | 4.5 (2.9) | ||
| Parent’s social life | 2.7 (2.5) | ||
| Parent’s life at home | 4.6 (2.8) | ||
| Overall mean (all items | 4.3 (.9) | 4.9 (1.6) | |
| Total score | 12.9 (7.6) | 24.5 (10.6) |
| SDQ adolescent | CSDS total score | SDQ parent | CSDS-P total score |
| Spearman’s rho (p) | Spearman’s rho (p) | ||
| Total difficulties score | .433* (<.001) | Total difficulties score | .370* (<.001) |
| Subscale score | Subscale score | ||
| Emotional problems | .457* (<.001) | Emotional problems | .342* (<.001) |
| Conduct problems | .011 (.914) | Conduct problems | .132 (.183) |
| Hyperactivity | .184 (.064) | Hyperactivity | .154 (.119) |
| Peer problems | .186 (.061) | Peer problems | .245* (.012) |
| Prosocial | .118 (.239) | Prosocial | – .298* (.002) |