Biomedical subjects

Robert Drake

Publications and source records attributed to Robert Drake.

8 recordsLinked to original sources

PubMed2006

Are there distinctive trajectory groups in substance abuse remission over 10 years? An application of the group-based modeling approach.

This paper introduces to mental health services and evaluation researchers a method for analyzing longitudinal data: a group-based modeling approach for applied research. We present the basic formulations of the model and illustrate its application by analyzing the 10-year longitudinal data on substance abuse remission from the New Hampshire Dual Disorders Study. The basic features of the approach are: identifying latent groups with distinctive trajectories, estimating the proportion of the population in each group, linking individual-level covariates to group membership, assigning individuals to different groups, and creating group profiles based on posterior probabilities. We also discuss cautions and the controversies surrounding this approach. The major findings include four groups with distinct trajectories of remission from substance abuse.

Female↗

PubMed2005

Integration of psychiatric and vocational services: a multisite randomized, controlled trial of supported employment.

OBJECTIVE: Although large-scale surveys indicate that patients with severe mental illness want to work, their unemployment rate is three to five times that of the general adult population. This multisite, randomized implementation effectiveness trial examined the impact of highly integrated psychiatric and vocational rehabilitation services on the likelihood of successful work outcomes. METHOD: At seven sites nationwide, 1,273 outpatients with severe mental illness were randomly assigned either to an experimental supported employment program or to a comparison/services-as-usual condition and followed for 24 months. Data collection involved monthly services tracking, semiannual in-person interviews, recording of all paid employment, and program ratings made by using a services-integration measure. The likelihood of competitive employment and working 40 or more hours per month was examined by using mixed-effects random regression analysis. RESULTS: Subjects served by models that integrated psychiatric and vocational service delivery were more than twice as likely to be competitively employed and almost 1(1/2) times as likely to work at least 40 hours per month when the authors controlled for time, demographic, clinical, and work history confounds. In addition, higher cumulative amounts of vocational services were associated with better employment outcomes, whereas higher cumulative amounts of psychiatric services were associated with poorer outcomes. CONCLUSIONS: Supported employment models with high levels of integration of psychiatric and vocational services were more effective than models with low levels of service integration.

Adult↗

PubMed2004

A method for analyzing longitudinal outcomes with many zeros.

Health care utilization and cost data have challenged analysts because they are often correlated over time, highly skewed, and clumped at 0. Traditional approaches do not address all these problems, and evaluators of mental health and substance abuse interventions often grapple with the problem of how to analyze these data in a way that accurately represents program impact. Recently, the traditional 2-part model has been extended to mixed-effects mixed-distribution model with correlated random effects to deal simultaneously with excess zeros, skewness, and correlated observations. We introduce and demonstrate this new method to mental health services researchers and evaluators by analyzing the data from a study of assertive community treatment (ACT). The response variable is the number of days of hospitalization, collected every 6 months over 3 years. The explanatory variable is group: ACT vs. standard case management. Diagnosis (schizophrenia vs. bipolar disorder), time, and the baseline values of hospital days are covariates. Results indicate that clients in the ACT group have a higher probability of hospital admission, but tend to have shorter lengths of stay. The mixed-distribution model provides greater specification of a model to fit these data and leads to more refined interpretation of the results.

Adult↗

PubMed2004

The STIRR model of best practices for blood-borne diseases among clients with serious mental illness.

OBJECTIVE: Persons with severe mental illness have a markedly elevated risk of several blood-borne infections, including HIV, hepatitis B, and hepatitis C. Prevention, early detection, and treatment of these disorders are crucial interventions for high-risk populations. However, because of a number of barriers, most clients with severe mental illness do not receive these basic best-practice services. The authors describe a public health model intervention designed to deliver basic best-practice services for blood-borne diseases, as specified by the Centers for Disease Control and Prevention, to clients with severe mental illness and co-occurring substance use disorders. METHODS: The intervention, called STIRR (for screen, test, immunize, reduce risk, and refer), is brief (requiring approximately one hour per client) and is delivered at the site of mental health care by a mobile team of specialists. Clients are provided with risk screening, testing for HIV and hepatitis, immunization for hepatitis A and B, risk-reduction counseling, and treatment referral for blood-borne infections. Also described is a pilot study to evaluate this model in two publicly funded community mental health centers. RESULTS: At the first site, 137 (79 percent) of clients with severe mental illness were tested and immunized. At the second site, more than two-thirds of the clients of a dual diagnosis team participated (67 clients, or 68 percent). Intervention costs per client ranged from 194 dollars to 262 dollars. CONCLUSION: S: The STIRR approach has the potential to provide a basic, best-practice package of interventions for high-risk clients with severe mental illness.

Adult↗

PubMed2003

Using discrete-time survival analysis to examine patterns of remission from substance use disorder among persons with severe mental illness.

Investigators in mental health research are often interested in examining critical events such as onset, relapse, and recovery from illness, including substance use disorders. As data on these critical events are often collected at discrete-time intervals (e.g., weekly, monthly, or yearly), discrete-time survival models are more appropriate than well-known continuous-time methods. In this paper, we present discrete-time survival analysis methods at an introductory level. Using data collected every 6 months from a 3-year study of assertive community treatment in New Hampshire, we show that discrete-time survival models can be used to analyze patterns of remission from substance use disorder among clients with severe mental illness. The main questions investigated are (1) when are remissions more likely to occur? and (2) what variables predict remission? The results indicate that remission is more likely to occur in the first 6 months and in the 3rd year of the study. Gender, age, baseline use of substances, and diagnosis are strong predictors of remission.

Case Management↗

PubMed2003

Limiting inpatient substance use treatment: what are the consequences?

This study tested whether a managed care policy of substituting outpatient for inpatient treatment of substance use disorders shifted treatment costs to psychiatric providers. This was an observational study, based on administrative data of 25,450 adult disabled Medicaid beneficiaries treated for schizophrenia and major affective disorders. Eighteen percent had a diagnosis of substance use disorder. Multivariate regression was used to determine the odds of having a hospital admission and the relationship of managed care to hospital length of stay and total per person treatment expenditures. Hospital admissions and length of stay for both substance use disorder and psychiatric treatment were reduced, but adults with a dual diagnosis had higher annual expenditures compared to those with only a psychiatric diagnosis. There was no evidence of cost shifting. Although emphasis on outpatient treatment did not result in cost shifting, the combination of substance use disorder and psychiatric illness remains an expensive public health problem.

Adolescent↗

PubMed2002

Cost-effectiveness of two vocational rehabilitation programs for persons with severe mental illness.

OBJECTIVE: This study sought to determine differences in the cost-effectiveness of two vocational programs: individual placement and support (IPS), in which employment specialists within a mental health center help patients obtain competitive jobs and provide them with ongoing support, and enhanced vocational rehabilitation (EVR), in which stepwise services that involve prevocational experiences are delivered by rehabilitation agencies. METHODS: A total of 150 unemployed inner-city patients with severe mental disorders who expressed an interest in competitive employment were randomly assigned to IPS or EVR programs and were followed for 18 months. Wages from all forms of employment and the number of weeks and hours of competitive employment were tracked monthly. Estimates were made of direct mental health costs and vocational costs. Incremental cost-effectiveness ratios (ICERs) were calculated for competitive employment outcomes and total wages. RESULTS: No statistically significant differences were found in the overall costs of IPS and EVR. Participation in the IPS program was associated with significantly more hours and weeks of competitive employment. However, the average combined earnings-earnings from competitive and noncompetitive employment-were virtually the same both programs. The ICER estimates indicated that participants in the IPS program worked in competitive employment settings for an additional week over the 18-month period at a cost of $283 ($13 an hour). CONCLUSIONS: The analyses suggest that IPS participants engaged in competitive employment at a higher cost. When combined earnings were used as the outcome, data from the statistical analyses were insufficient to enable any firm conclusions to be drawn. The findings illustrate the importance of choice of outcomes in evaluations of employment programs.

Cost-Benefit Analysis↗

PubMedDate not supplied

Quantification of composition and domain sizes of industrial poly(phthalamide)/poly(dimethylsiloxane) block copolymers using different 1H solid state NMR methods.

We have applied several 1H solid state NMR techniques to obtain structural information on industrial silicone copolymers as thermoplastic elastomers that proved difficult to be analysed by conventional techniques. Static measurements were applied to achieve the separation between mobile and rigid parts. To get structural information fast magic angle spinning at 25 kHz in combination with a high field of 700 MHz was used. 1H spin diffusion was applied to determine the domain sizes of the micro phase-separated polymer components.

Dimethylpolysiloxanes↗