Participants
The recorded data of all the patients (n=400) who were aged between 6 and 18 years, followed up at our outpatient ADHD clinic (mean follow-up duration of 4.5 years), and were evaluated between January 1st, 2019, and December 30th, 2020, was analyzed retrospectively. Due to missing data, 53 patients were excluded, therefore the total number of patients included to the study was 347.
The ADHD diagnosis of participants was confirmed through clinical assessment according to the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime (K-SADS-PL). The participants were excluded if there was found inadequate evidence supporting the diagnosis of ADHD.
Measures
Sociodemographic questionnaire
A questionnaire evaluating the sociodemographic features of the children, symptoms at the initial visit, current problems, ADHD presentations, comorbidities, duration of diagnosis, and treatment were created by the researchers. Sociodemographic data were collected from the patients’ medical records.
Schedule for affective disorders and schizophrenia for school-age children-present and lifetime (K-SADS-PL)
This is a semistructured diagnostic interview searching the past and current psychiatric disorders in child and adolescent psychiatry. In the current study, it is administered to assess the presentations of ADHD and comorbid diagnoses. Its reliability was established by Gokler and colleagues [19].
The child and adolescent disruptive behavior disorders screening and rating scale based on DSM-IV (Turgay’s scale- DBD-SRS)
This scale was developed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria of ADHD, Oppositional Defiant Disorder (ODD), and Conduct Disorder by Turgay. Turkish validity and reliability study was conducted by Ercan and colleagues. It includes 41 questions assessing the following areas: 9 for attention deficit, 9 for hyperactivity and impulsivity, 9 for the oppositional defiant disorder, and 15 for conduct disorder. Each question is rated as 0= none, 1= some, 2= quite, or 3= much. Higher scores indicate greater severity [14].
Child behavior checklist (CBCL)-sluggish cognitive tempo subscale (SCT)
The CBCL is a screening tool for psychopathology that is based on parent reportings and consists of 118 items. Parents rated each question as 0=not true, 1=somewhat or sometimes true, or 2=very true or often true based on the presence of the symptom within the past 6 months. The CBCL provides two broad-band scales for externalizing and internalizing problems and narrow-band scales for specific symptom groups. We used the CBCL-SCT subscale for the assessment of SCT features. As the frequency and severity of behaviors were rated with using Conners Rating Scales, we did not apply the other subscales of CBCL. The SCT subscale was derived from four items: (1) lacks energy, (2) confused, (3) daydreams, and (4) stares. The highest possible score on the subscale was 8 and the lowest possible score was 0. Measurement structure of the Turkish version has been performed and the internal consistency for the SCT subscale was α = 0.71 [13].
Conners rating scales revised- parent and teacher (CPRS-R, CTRS-R)
Conners Rating Scales-Revised scales for the parents (CPRS-R) and teachers (CTRS-R) were used. The CPRS-R has 80 items that require the parent to rate the frequency and severity of each behavior. The CPRS-R has seven subscales: Cognitive Problems-Inattention, Oppositional-Defiant behavior, Hyperactivity, Anxiety, Perfectionism, Social Problems and Psychosomatics subscales. Internal consistency was found to be 0.55 and 0.85, test-retest reliability was 0.42 and 0.74 [12]. CTRS-R has 59 items on a Likert scale and consists of six subscales: cognitive problems-inattention, oppositional-defiant behavior, hyperactivity, anxiety, perfectionism, and social problems subscales. Both CPRS-R and CTRS-S scales consist DSM-IV Index that includes DSM-IV diagnostic criteria, ADHD Index and Global Index as auxiliary tools to determine the presence of ADHD according to DSM-IV criteria. Internal consistency was found as 0.72 and 0.90, test-retest reliability was found as 0.49 and 0.99 [22].
Wechsler intelligence scale for children – revised form (WISC-R)
Verbal, performance, and total scores of the Wechsler Intelligence Scale for Children-Revised (WISC-R) were used to determine the intelligence levels of the children. Standardization of the WISC-R for Turkish children was performed by Savaşır and Şahin. The split-half reliability was 0.97 for verbal, 0.93 for performance sections, and 0.97 for total scores [27].
Procedure
The records of patients were scanned and the data used were gathered. According to our standard assessment procedure of ADHD outpatient clinic, firstly the patients and their parents who had been referred with symptoms related to ADHD were interviewed together at the initial visit, sociodemographic data were collected, and the scales were handed out to the parents. WISC-R tests were implemented by clinical psychologists.
The interviews conducted with parents and patients were performed by the child and adolescent psychiatrists to gather information about the detailed developmental history and emotional/behavioral symptoms and standardized rating scales (CBCL 6-18, CPRS-R, CTRS-R) completed by parents and teachers were collected. Besides the scales, parents and patients were asked about symptoms at baseline and follow-up visits; responses were scored as 0 = no and 1 = yes (for example; “Does s/he have irritability,” “Does s/he have academic problems”). It is considered “yes” if at least one said “yes.”
The data analyzed in this study were collected by three experienced child and adolescent psychiatrists by reviewing the recorded information about patients. The accuracy of ADHD diagnosis was also evaluated according to the scales and symptoms of the patients. This study was evaluated and approved by the medical ethics committee of our university (İ05-193-19, 01.11.2019), and the protocols were in accordance with the Declaration of Helsinki.
Statistical analysis
The variables were investigated using visual (histograms, probability plots) and Kolmogorov Smirnov test to determine whether or not they are normally disturbed. The independent sample t-test was used to analyze group differences for parametric variables. The Mann-Whitney U test was used for nonparametric variables. The chi-square or Fisher’s exact tests were used for categorical variables. When investigating the changes in the scales by SCT groups, the effect of gender was adjusted using two-way ANOVA. Statistical analyses were performed using SPSS version 22 (IBM SPSS Inc., Chicago, IL, USA) and p-values <0.05 were considered statistically significant.