[Towards a better assessment of child and adolescent mental health status. Polish version of strengths and difficulties questionnaire. Experiences from two population studies].

Background: There is a need for a brief validated instrument, that could be used in Poland in population studies to monitor mental health problems in children and adolescents. Goodman's Strengths and Difficulties Questionnaire (SDQ) has been used in epidemiological studies in many countries, to our knowledge, not yet in Poland. SDQ has 25 items and a supplement on the impact of these difficulties for the child and the family. Scoring system includes one total score generated on the basis of 20 main items, and partial scores for four subscales concerning: emotional symptoms, conduct problems, hyperactivity and peer problems. THE AIM of this study was: to evaluate the Polish version of SDQ on the basis of two large population studies, to assess the prevalence of mental health problems in youth and to discuss existing norms.

Material: For the first time self-reported and proxy (parents) SDQ was used in Poland in a national mail survey conducted in 2003 within the KIDSCREEN project. In the present study a subsample of 774 children in average age 14.3 years was considered. For the second time, an improved self-reported version of SDQ was used in a school-based survey carried out in 2006 within HBSC project on the representative sample of 5270 pupils in comparable average age of 14.0 years.

Results: Factor analysis, performed on the basis of the second survey, suggested a four-component structure of SDQ-20, however it was different than in the original scale. Only peer subscale was fully replicated. Emotional subscale could include in Polish version more than five original items, while hyperactivity and conduct subscales had less than five items with high enough factor loadings. The internal consistency of the full questionnaire was much better than for four subscales. Distributions of total SDQ scores were similar in both surveys. According to the HBSC study, borderline or noticeable scores were reported by 17.7% young respondents, according to previous KIDSCREEN study by 14.9% adolescents and 18.8% parents as proxy respondents.

Conclusions: SDQ is a promising instrument for monitoring mental health problems in children and adolescents, however the Polish adaptation is still not as reliable as could be expected. To complete the validation process, especially convergent validity in comparison to other instruments measuring the same concept should be conducted, as well as discriminative validity studies in clinical settings.