2006, Number 6
Brief screening and diagnostic questionnaire for mental health problems in children and adolescents: reliability, standardization, and construct validity. Part one
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Studies on developmental psychopathology have shown that several problems and disorders that started during childhood persist into adulthood. During adolescence, some disorders become risk factors for substance abuse, suicidal conducts, unwanted pregnancies, and violence. Also, results from the International Consortium in Psychiatric Epidemiology (ICPE), including data from Mexico City, have found that an early onset of anxiety disorders preceded substance abuse and dependence, emphasizing the need to early identify and treat mental problems that may eventually lead to other psychopathologies, thus requiring systematic and programmed preventive interventions.
Children account for one third of all psychiatric consultations, usually arriving with chronic disorders and several complications. With this in view, the need to develop a useful instrument to early identify clinical risk conditions in children by health professionals was considered.
In Mexico, our epidemiological work on children’s mental health started at the end of the 1980’s using the Report Questionnaire for Children (RQC), which is a 10-item screening instrument developed at the end of the 1970’s for a WHO collaborative research with the aim of extending psychiatric services to primary care settings. In our population, the instrument showed good efficiency with a positive predictive value (PPV) of 76% and a negative predictive value (NPV) of 99%. Different studies have shown the magnitude of mental health problems in children, as well as the association of these problems with parents’ depression and alcohol abuse. However, the need to identify what kind of disorders are they and estimating their prevalence remains.
The Brief Screening Diagnostic Questionnaire (CBTD) was built based on the previous experience using the RQC. Seventeen items exploring symptoms frequently reported as motives for seeking attention at the out-patient mental health services were added to the original 10 questions of the RQC. Most of them are items included in the CBCL-P, exploring hyperactivity, impulsivity, attention deficit, sadness, inhibition, oppositional and antisocial behaviors, as well as eating behaviors associated with low or high weight. The aim was to include cardinal symptoms which may lead to identify probable specific syndromes and disorders, based on the parent’s report.
The present study shows how the CBTD was tested and further developed using the information gathered from a general population sample. The hypotheses were the following:
1. More than 50% of the children and adolescents would be reported asymptomatic or with only one or two symptoms.
2. It is expected that for those children and adolescents showing more symptoms these would form groups suggesting the presence of probable psychiatric syndromes as defined by the DSMIV and ICD-10 classifications.
The CBTD was included as part of the instruments used in an epidemiological study on psychiatric morbidity in Mexico City. The study was designed as a household survey on a representative sample of the adult population aged 18-65 years in Mexico City. In addition, information was obtained about all the respondents’ children aged 4-16 years living at the same household. The total sample included 1685 children and adolescents with the following distribution by age groups: 4-5 years old: 16.3%; 6-8 years old: 25.5%; 9-12 years old: 30.9%, and 13-16 years old: 27.4%. Analysis was carried out as follows: First, the internal consistency of the new instrument was measured using the Kuder-Richardson coefficient. Using the CBTD as a scale, the score distribution on the total population, as well as for sex and age groups, was statistically studied, thus obtaining the median and percentiles with 95% confidence intervals, in order to establish the norm and define caseness.
Next, as the answers to the CBTD questions are dichotomic, cluster analysis was used to identify group symptoms and test the construct validity of the instrument. Additionally, factor analysis using the principal component extraction and maxim likelihood methods, as well as different rotations of the factors, were obtained and compared with results from the cluster analysis.
Internal consistency was 0.81 with a 0.75-0.85 range by age groups, indicating that the instrument can be used reliably as a scale.
Asymptomatic children represented 48.6% and another 17% were reported with only one symptom, thus sustaining the first hypothesis of this study.
The cut-off point for defining caseness was the report of five symptoms or more, which was the upper 95% confidence interval for the 90th percentile.
Cluster analysis identified eight groups of symptoms named as follows: Inhibition, anxiety, enuresis, dissocial, delayed or backwards, attention, mood, and conduct. Similar results emerged from the factor analyses, indicating that the instrument indeed pictures different behavior constellations that correlate with the most frequent syndromes seen in children and adolescents.
Discussion and conclusion
It is important to highlight that the CBTD is based on symptoms which are frequently reported as motives for consultation. So, the instrument does not merely translate diagnostic criteria into questions but rather uses the way in which the population perceive and express concern about their children’s behavior in order, first, to define caseness and, second, to identify probable disorders.
Results show that the CBTD has good internal consistency and construct validity for identifying groups of symptoms that suggest the presence of the most frequent psychiatric syndromes in children and adolescents. In this way, the CBTD accomplishes the objective of developing a brief screening instrument that may be useful for epidemiological studies, for screening at general and pediatric practices and, most important of all, for the surveillance of the mental health in childhood and adolescence.
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