No abstract

The prevalence and course of alcohol and drug use were examined in a longitudinal, retrospective study of 100 schizophrenic outpatients. During the 18 month study period, problem substance use (abuse and dependence) was not associated with differential attrition from outpatient treatment. Thirty to forty percent of subjects were using drugs or alcohol during any evaluation period. The overall level of substance use and problem use of alcohol, marijuana, and other drugs remained stable, while problem use of cocaine and multiple substances increased over time. Problem substance use was associated with lower functional status and the detrimental effect of problem substance use appeared to increase with time. These findings underscore the need to address substance use problems in the context of outpatient schizophrenia treatment.

Measuring preferences for schizophrenia outcomes facilitates meaningful integration of multiple outcome measures and multiple perspectives on treatment outcomes. The Time Tradeoff (TTO) technique, specifically developed for measuring health state preferences, is used widely in health research, but some evidence suggests that the TTO may work less well with schizophrenia than with other health conditions. This study tested the hypotheses that tailoring the time frame of the standard TTO to the course of schizophrenia and simplifying its presentation format would improve its feasibility and efficiency. Forty clinicians provided TTO ratings using 1 of 4 combinations of time frame and presentation format. Numeric ratings and quantitative and qualitative measures of feasibility showed that while participants preferred the simpler format, none of the alterations improved feasibility. Participants' ratings were prone to logical inconsistencies and participants found all 4 versions of the TTO confusing and poorly suited to the context of schizophrenia treatment.

Quantifying the importance of treatment outcomes by measuring preferences allows construction of aggregate outcome indicators that reflect the relative importance of multiple outcomes, trade-offs between outcomes, and the perspectives of different stakeholders. However, standard preference assessment methods are cognitively complex and may be particularly challenging for persons with schizophrenia and other serious mental illnesses. Preferences may not be meaningful or comparable across stakeholder groups if the groups do not use the methods in similar ways. This study combined qualiative and quantitative methods to compare comprehension and decision strategies across three standard preference assessment methods (Rating Scale, Time Tradeoff, and Paired Comparison) in 2 stakeholder groups (consumers of schizophrenia treatment and clinicians). Results indicate that the Rating Scale method is likely to yield the most valid and comparable preference values because it is well understood and acceptable to both consumers and clinicians. Both groups found the Time Tradeoff method difficult to use and poorly suited to evaluating schizophrenia outcomes.