In the present study, comparing QoL between psychiatric outpatients and regular students recruited from the same catchment area and during comparable time intervals and matched for sex and age, we found outpatients to report, and be reported by their parents with, significantly lower QoL than did students. Moreover, when also matching for levels of emotional and behavioural problems in the two different groups, the outpatients still reported lower QoL levels than students. Finally, when also excluding students in the general population who had received services in alternative settings or had a history of mental health referral the outpatients still reported, and were reported with, significantly lower QoL levels than students.
Child report of QoL among outpatients and students with equal levels of emotional and behavioural problems
Our results indicate that QoL self-report could identify psychiatric health services needs that are not detected by a well-established, widely used, reliable, valid and comprehensive assessment instrument for mental health problems/psychopathology in children. The results showed that even when the outpatients were matched with students for levels of emotional and behavioural problems, they still reported significantly lower QoL levels than did the students. Therefore, QoL could add important information about the child's perceived well-being beyond that provided by only considering mental health or psychopathological aspects, at least when measured as parent reported emotional and behavioural problems on the CBCL.
The child's QoL as measured by the ILC refers to subjective well-being and satisfaction, according to his/her experience in several life domains such as in the family, with peers, in school, in activities when the child is alone, and in regard to his/her physical and mental health, together with a global rating of wellbeing [32, 39]. Our results suggest that given two children with equal levels of mental health problems, QoL measurement would add important information about the patient. The reduced QoL experience in outpatients, compared to non-patients with equal mental health problems, would suggest referred children have more psychiatric health services needs that cannot be explained solely by their mental health problems.
In addition to specific information about the child's QoL as mentioned above, the ILC also provides information whether certain life domains are perceived as problematic or non-problematic. Our results show also that even when the outpatients were matched with students for levels of emotional and behavioural problems they reported a larger number of problematic life domains than did the students. Even if the child perceives a markedly reduced QoL in one or two life domains, areas where there are no problems can represent potential strengths for the child. The clinician may find it useful to build on such assets in treatment planning. Thus, assessment of QoL using an instrument such as the ILC can provide a fuller picture of children's needs and opportunities when presenting to mental health clinics.
Parent report of QoL among outpatients and students with equal levels of emotional and behavioural problems
Parents of outpatients reported lower child QoL levels when compared to parents of students in the general population, even when controlling for levels of emotional and behavioural problems in the child (as reported by the parents). However, this significant difference was only observed after exclusion of those patient-student pairs where the student's parent had answered positively to the question: "Has your child received any help during the last year due to mental health problems or learning difficulties?"
Interpretation of this finding is not straightforward. These parents of children in the school population obtaining help because of child mental problems or learning difficulties might be in a quite different situation than those of children in the school population, who have not obtained any help (most of them probably because there is no need for any help).
Parents of students could have received help for their child from community primary care services but they actually may have perceived this help as inadequate due to limited special mental health service capacities. They therefore could have rated child QoL as lower than did parents of healthy children, thereby reducing the difference between patient's and student's parent proxy reports. Without excluding the "having received help" group from the analysis parents of outpatients and students did not report any significant difference on child QoL (see Table 4). We feel this finding further reinforces the need for both child and parent proxy report in QoL assessment because it seems that obtaining help for one's child because of mental problems or learning difficulties affected the student's parent proxy, but not the child reports in the present study.
Not excluding students who had received help lead to non-significant difference between parent report of students and patients and might be interpreted mistakenly. Given non-significant differences between parent proxy reports and significant differences between self-reports, the additional discrimination of QoL measures in addition to the parent reported CBCL could simply be interpreted as a result of the self-report perspective. However, we found that parent-report QoL measures as well as self-report could add important information about the child's perceived well-being beyond that provided by only considering measures of mental health or psychopathology, at least when considering parents in the school population who's child did not received help recently.
Help provided in the school-sample and the problem of double participation
Identification of children in school-samples is typically impossible due to ethical reasons for protecting anonymity, as it was in the present study. Some students might therefore have participated both in the school-based and clinical sample when targeting the same catchment area, which could bias the results. We do not know exactly where these students had received help, such as from either primary care services for students (i.e. general practitioners, nurses, school psychologists) or our specialized child psychiatric service. About 2-3% of the county's total child population, aged 0 to 18 years, received specialized psychiatric services (Annual Reports for 2003; BUP-Aarsmelding St. Olav Hospital in Trondheim). For children 8-15.5 years this figure is estimated somewhat higher or about 4%. Eight percent of the students (aged 8-15.5 years) in the total school-sample were reported by their parents to have received help for their child. Thus, up to one-half of these students who received some kind of help might have had contact with our specialized psychiatric service. When we matched patients and students on the CBCL, 33% of the student's parents reported having received help. Therefore, roughly, at maximum one half of them (15%, N = 15) could have participated in both the school and clinical sample. However, as discussed above, we conducted analyses both with and without students who had received such help, thereby partly controlling for confounding by overlapping samples.
Strengths and Limitations
When controlling for sex and age we found both outpatients and their parents to report lower QoL than did students and their parents. These results are consistent with outcomes of other clinical studies examining QoL by child [3, 7, 9, 14, 18] and parent proxy [3, 8, 9, 11, 18] report, thereby validating our study. Other strengths of the present study were that we compared outpatients with students matched for sex and age, and that both child and parent proxy reports of QoL were obtained. In addition all subjects resided in the same health care catchment areas and assessments were carried out in closely related time periods in both groups. When controlling for emotional and behavioural problems, the observed additional discriminatory power provided by the ILC might have been contained in the CBCL, but might not be accessible due to matching by using only the Total Problem score. However, after the matching procedure we found no significant differences neither on the Externalizing nor the Internalizing subscales, thereby partly controlling for any such confounding.
However, there were several limitations with the study. The ILC being brief, does not address psychosocial functioning in detail. Although, the concept of "inner" QoL indirectly also reflects the child's subjective perception of his/her functioning on different life domains, "psychosocial functioning" often refers to more "objective" aspects of the individual's life. "Psychosocial functioning" is important for both the QoL and mental health perspective, but can best be evaluated from an external perspective , for example by achievements in school, size and number of contacts with social network, and/or diagnostic ratings of psychosocial functioning by a clinician. However, the resources available for the present study did not permit such assessment, especially not in the student comparison group.
Another limitation is that we did not include self-reports of mental health, such as with the YSR, even though we included the child perspective in QoL measurements. We did not use the YSR (which is constructed for children aged 11 years and older) in the present study because that would considerably reduce the size of our present clinical sample leading to reduced power corrupting the results. Further, there is no other comprehensive, reliable, valid and well-established instrument for assessing mental health by self-report for the youngest children. However, research on mental health and QoL in the younger age group is important because school services play a central role in providing support and early detection of children who need to be referred to mental health services .
Furthermore, the information on child emotional and behavioural problems was obtained by questionnaires, and not by semi-structured clinical interviews conducted by clinical professionals, which are acknowledged as the gold standard. However, interviews are difficult to incorporate in epidemiological studies.
Lastly the present study was limited to one county in central Norway. Although this included children from rural, semirural as well as urban areas, the population is highly homogenous in race/ethnic make up. Moreover, socioeconomic status is more restricted in Norway than in most countries.