Probing the relative contribution of the first and second responses to sensory gating indices: a meta-analysis.

Sensory gating deficit in schizophrenia patients has been well-documented. However, a central conceptual issue, regarding whether the gating deficit results from an abnormal initial response (S1) or difficulty in attenuating the response to the repeating stimulus (S2), raise doubts about the validity and utility of the S2/S1 ratio as a measure of sensory gating. This meta-analysis study, therefore, sought to determine the consistency and relative magnitude of the effect of the two essential components (S1 and S2) and the ratio. The results of weighted random effects meta-analysis revealed that the overall effect sizes for the S1 amplitude, S2 amplitude, and P50 S2/S1 ratio were -0.19 (small), 0.65 (medium to large), and 0.93 (large), respectively. These results confirm that the S2/S1 ratio and the repeating (S2) stimulus differ robustly between schizophrenia patients and healthy controls in contrast to the consistent but smaller effect size for the S1 amplitude. These findings are more likely to reflect defective inhibition of repeating redundant input rather than an abnormal response to novel stimuli.

Health issues in the Arab American community. Arab Americans in publicly financed substance abuse treatment.

OBJECTIVE: To determine the characteristics of Arab Americans receiving treatment and to compare them with individuals of other ethnic groups. METHODS: We used admission data (FY2005) for Michigan publicly funded substance abuse treatment (N=69,989). Arab American ethnicity (n=224 or 0.3% of admissions) was defined by codes for race, ethnicities or primary language of Arabic (n=21). Other ethnicities examined were American Indian, Hispanic, African American, and White. RESULTS: The number of Arab American admissions was lower than expected for the population (RR=0.25). Admissions were concentrated (81%) in metropolitan Detroit as is the community (82%, RR=.99), unlike other ethnicities. Primary drugs of abuse were alcohol (34.8%), marijuana (17.9%), heroin (17.4%) and crack cocaine (15.6%). Mean duration of use (11.2 yrs) was significantly lower than for other ethnicities. Arab American admissions were predominately male (76.3%), unemployed (62.1%) and with criminal justice involvement (58%), similar to other ethnicities. DISCUSSION: Using administrative database has its limits and may misclassify ethnicities. Based upon the available data, it appears that Arab Americans accounted for a small percentage of admissions to publicly funded substance abuse treatment in Michigan. Most of the admissions listed English as the primary language, raising concern that language may be a barrier to entry. Admission profiles were generally similar across ethnicities, except that Arab Americans were entering treatment after shorter duration of use. These data can inform development of treatment programs and outreach efforts.