Substance use among young offenders: thrills, bad feelings, or bad behavior?

The relationships of conduct problems, attention deficit hyperactivity disorder (ADHD) signs, and depression to substance use were examined between 1994 and 1999 among 900 incarcerated young offenders in South Australia, 206 of whom were reassessed when later readmitted to secure care. At the first and second assessments, conduct problems, ADHD signs, and depression scores all had significant concurrent associations with a measure of recent substance use. Prospectively, there were no significant associations between depression and substance use. At the zero-order level, both ADHD signs and conduct problems predicted future substance use. ADHD signs remained significantly predictive after controlling for concurrent associations. The results lend support to the view that substance use is related to general deviance and that the arousal needs associated with increased ADHD signs increase the risk of substance use. There was no support for the view that substance use in this population is self-medication in response to internalizing problems.     

Down's syndrome screening: population statistic dependency of screening performance

BACKGROUND: The choice of parameter sets used to calculate Down's syndrome risks is important. This study details analysis of samples from affected and unaffected pregnancies and evaluates whether published population data is optimal. Screening efficiency realized with measurement procedure-specific population parameters is compared with selected population sets available in the literature. METHODS: In a retrospective experiment, double and triple testing was performed on maternal serum samples from 286 randomly chosen unaffected singleton pregnancies and 95 Down's syndrome affected pregnancy samples. Using a risk cut-off of 1 in 250, detection rates and false positive rates were estimated for different population settings to select a model giving the best overall efficacy. Receiver operation characteristics curve analysis was performed and detection rates realized with the different population settings was estimated at a 5% fixed false positive rate. RESULTS: Geometric mean weight corrected multiples of the median values were 1.01 for alpha-fetoprotein (AFP), 1.02 for human chorionic gonadotropin (hCG) and 1.01 for unconjugated estriol (uE3) in unaffected pregnancies and 0.77 (95% CI: 0.71-0.83) for AFP, 2.42 (95% CI: 2.17-2.71) for hCG and 0.78 (95% CI: 0.73-0.83) for uE3 in affected pregnancies. Differences in double and triple risks obtained with the different models were significantly different from each other (p < 0.001). At a cut-off of 1 in 250, the maximum triple test detection rate was 75.8% for a false positive rate of 4.9% and was obtained with the measurement procedure-specific setting. At a fixed false positive rate of 5%, the maximum detection rate for the triple test was 77.9% (95% CI: 62.2%-85.8%). The maximum double test detection rate at 5% false positive rate was 69.6% (95% CI: 59.5%-78.5%). Except for two models, the area under the curve for the triple test was higher than that of the double test. CONCLUSIONS: The Access triple test meets the typical performance characteristics for this test combination. The assay-specific settings yielded the overall best efficacy for the criteria studied. Therefore, the availability of measurement procedure-specific mid-trimester reference values for unaffected and affected pregnancies in prenatal screening programs is essential. Such reference values are established for the Beckman Coulter Access triple test: maternal serum AFP, uE3 and hCG.     

Radiophosphate evaluation of loose hip prostheses

There were 23 patients who had revisions of their failed hip arthroplasties and a prior radiophosphate assessment of the joint components. In this selected group of patients the true positive incidence of abnormal scintigraphic findings for femoral component loosening was 19 out of 20 (95%) and the true negative incidence was two out of two by the criteria adopted. The true positive incidence of such findings, indicating acetabular component loosening, was seven out of seven, and the true negative was nine out of 10. Some of these patients also had contrast arthrography and the incidences of true positive and true negative findings for femoral component loosening were seven out of 15 (47%) and one out of one, respectively. Prediction of the status of the acetabulum was poorer using this technique with true positive and true negative incidences of four out of nine and two out of five, respectively.