Depression among Australian adolescents.

OBJECTIVES: To examine the prevalence and factors associated with depression in Australian adolescents. DESIGN: A representative, multistage probability sample of Australian households conducted in 1998 (part of the National Survey of Mental Health and Well-being). Adolescents completed self-report questionnaires and parents were interviewed using a lay-administered, structured psychiatric interview and several questionnaires. PARTICIPANTS: 1,490 adolescents aged 13-17 years and their parent or main caregiver. MAIN OUTCOME MEASURES: Prevalence of depression in adolescents, as reported by parents and by adolescents themselves; demographic factors; health-risk behaviours; and rate of use of support services. RESULTS: Of the 1,490 adolescents originally sampled, 150 (10%) did not complete responses to questions on depression and were excluded from the analysis. Seventy of the remaining 1340 adolescents (5.2%; 95% CI, 4.0%-6.4%) met criteria for self-reported depression. Agreement between parent- and adolescent-reported depression was poor (kappa=0.27). Adolescent-reported depression was associated with increased suicide plans (odds ratio [OR], 2.83; 95% CI, 1.19-6.70) and attempts (OR, 9.05; 95% CI, 3.49-23.50) in the previous year, use of marijuana 10 or more times in the previous month (OR, 2.88; 95% CI, 1.25-6.64), having conduct disorder (OR, 4.09; 95% CI, 1.23-13.63) and use of school support services (OR, 4.71; 95% CI, 1.82-12.22). Those who used any kind of support service (24/70; 34%) used a mean of 2.9 services (mode, 2; range, 1-5). Three per cent (2/70) of depressed adolescents had been treated with antidepressants. CONCLUSIONS: Depressed adolescents exhibit higher rates of health-risk behaviours and psychosocial impairment than non-depressed adolescents, but only a small number receive appropriate treatment. Staff working in school-based services should be trained to identify adolescents with depression and facilitate referral for treatment.

Does breastfeeding at six months predict cognitive development?

There is controversy over whether the method of feeding in infancy affects intellectual development. We investigated the relationship between breastfeeding status at 6 months of age and long-term cognitive development in a cohort of 375 children born in Port Pirie, South Australia, between 1979 and 1982. Cognitive assessments were conducted at ages 2, 4, 7 and 11 to 13 years. After adjustment for sociodemographic, environmental and biomedical factors, a small, statistically non-significant, beneficial effect of breastfeeding on cognitive functioning was observed. Compared with the bottle-fed children, the breast-fed children had a 3.4 (95% CI -0.1 to 6.9), 1.3 (-2.3 to 4.9), 1.2 (-2.0 to 4.4) and 0.8 (-1.9 to 3.5) point advantage on the Bayley Mental Developmental Index at age 2 years, the McCarthy General Cognitive Index at age 4 years and the Wechsler Full-Scale IQ at ages 7 and 11 to 13 years, respectively. Our data suggest that any beneficial effect of breastfeeding on cognitive development is quite small in magnitude.

Sociodemographic factors modifying the effect of environmental lead on neuropsychological development in early childhood.

A long-term prospective cohort study was conducted to examine the association between prenatal and postnatal exposure to environmental lead and childhood neuropsychological development. The possible interactive effects of blood lead and some covariates on early development were explored in this study. Our data suggest that gender of the child modifies the effect of lead on the neuropsychological development during early childhood. At the ages of 2 and 4 years, girls appear to be more sensitive than boys to the neuropsychological effects of lead. However, there is no significant modification of the effect of lead by some other covariates, such as parental smoking, socioeconomic status, home environment, birth weight, and the kind of infant feeding. Evidence of interactions between environmental lead exposure and other covariates in the causation of neuropsychological deficits in childhood underscores the desirability of considering both main effects and interactions in this area of research. Such effects, if confirmed, may have implications for public health intervention strategies.

The prevalence of emotional and behaviour disorders and patterns of service utilisation in children and adolescents.

This study compared the prevalence of emotional and behavioural disorders in children attending schools of different socio-economic class. In addition, the study compared the rate of service utilization by children with and without disorders. Using cutoff scores recommended for use with Australian children, the prevalence of disorders in schools of different socio-economic class ranged from 2.3 +/- 2.2 to 13.9 +/- 5.3 per 100 children, with the highest prevalence being found in the lower socio-economic class schools. Although few children with disorders had been seen in a mental health clinic, advice had been sought from other services with regard to 66% of these children. This high rate of service utilization by children with disorders highlights the key role that general practitioners, school guidance officers and hospital services could play in facilitating the early identification and management of children with emotional and behavioural disorders.

Determinants of blood lead concentrations of pregnant women living in Port Pirie and surrounding areas.

In the context of a wider prospective investigation into the effects of cumulative exposure to lead, in utero and postnatally, on the outcome of pregnancy and growth and development in early childhood, 831 pregnant women who were living in Port Pirie, South Australia, the site of Australia's largest lead smelter, were recruited between May 1979 and May 1982, and the various factors that were likely to influence their blood lead concentration were examined. No significant difference in blood lead level was found among different stages of pregnancy. Higher concentrations of blood lead were measured in women who resided in areas of high soil lead content and in women who had resided in Port Pirie for three or more years. A low socioeconomic status, the use of water from the reticulated water supply rather than rainwater, an age of 21 years or less, a high body mass index, a low dietary intake of calcium, and cigarette smoking were all factors that were associated with a higher blood lead concentration. Lower blood lead concentrations were observed in women who took iron and folic acid to supplement their diet. Multiple regression analysis of average antenatal blood lead levels confirmed most of the univariate associations.