Substance abuse and quality of life among severely mentally ill consumers: a longitudinal modelling analysis.
ABSTRACT Evidence suggests that substance abuse negatively affects both psychiatric symptom severity and quality of life (QOL) in people with severe mental illness (SMI). However, these relationships have not been examined simultaneously, nor have they been characterized over time. Thus, it is difficult to appreciate the extent to which substance abuse exerts an enduring effect on psychiatric symptoms and distress and/or QOL in this population. The purpose of this study is to test a conceptual model linking these factors together.
Subjects were participants in a longitudinal evaluation of community mental healthcare in Ontario (n = 133). Comprehensive consumer assessments were conducted at treatment entry, and at 9 and 18 months. Subjects were receiving intensive case management or assertive community treatment throughout the 18-month study period. Structural equation modelling was used to examine the concurrent and longitudinal relationships between substance abuse, symptoms and distress, and QOL.
The prevalence of substance abuse was 55.0%. The SEM analysis suggested that substance abuse at baseline was associated with elevated symptomatology and distress and lower QOL, and that these effects endured after 18 months of treatment. Psychiatric symptoms and distress mediated the negative relationship between substance abuse and QOL.
The mediating role played by symptom and distress levels in the relationship between substance abuse and QOL suggests the importance of closely monitoring changes in these factors among SMI patients with substance problems. Tracking symptom severity and distress levels over time will allow service providers to intervene and potentially improve the QOL of individuals with SMI.
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ABSTRACT: Quality of life (QOL) assessment is a key component of many clinical studies and frequently requires the use of single global summary measures that capture the overall balance of findings from a potentially wide-ranging assessment of QOL issues. We propose and evaluate an irregular multilevel latent variable model suitable for use as a global summary tool for health-related QOL assessments. The proposed model is a multiple indicator and multiple cause style of model with a two-level latent variable structure. We approach the modeling from a general multilevel modeling perspective, using a combination of random and nonrandom cluster types to accommodate the mixture of issues commonly evaluated in health-related QOL assessments--overall perceptions of QOL and health, along with specific psychological, physical, social, and functional issues. Using clinical trial data, we evaluate the merits and application of this approach in detail, both for mean global QOL and for change from baseline. We show that the proposed model generally performs well in comparing global patterns of treatment effect and provides more precise and reliable estimates than several common alternatives such as selecting from or averaging observed global item measures. A variety of computational methods could be used for estimation. We derived a closed-form expression for the marginal likelihood that can be used to obtain maximum likelihood parameter estimates when normality assumptions are reasonable. Our approach is useful for QOL evaluations aimed at pharmacoeconomic or individual clinical decision making and in obtaining summary QOL measures for use in quality-adjusted survival analyses.Statistics in Medicine 02/2012; 31(11-12):1249-64. · 2.04 Impact Factor
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ABSTRACT: The Crisis Intervention Team (CIT) model is a specialized police response program for people in a mental illness crisis. We analyzed 2174 CIT officers' reports from one community, which were completed during a five year period. These officers' reports described interactions with people presumed to be in a mental illness crisis. We used hierarchical logistic and multinomial regression analyses to compare transport to treatment to either transport to jail or no transport by how the calls were dispatched. The results revealed that both dispatch codes and officers' on-scene assessments influenced transport decisions. Specifically, calls dispatched as suspected suicide were more likely to be transported to treatment than calls dispatched as mental disturbance. Furthermore, calls dispatched as calls for assistance, disturbance, suspicious person, assault, suspicion of a crime, and to meet a citizen were all less likely than mental disturbance calls to result in transportation to treatment. Officer assessments of the use of substances, being off medications, signs and symptoms of mental or physical illness, and violence to self or others were associated with the likelihood of being transported to treatment. These results build on previous work that demonstrated differences in transport decisions between CIT trained and non-CIT trained officers.International Journal of Law and Psychiatry 01/2011; 34(1):30-8. · 1.19 Impact Factor
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ABSTRACT: Aim: This study explored the associations of personal, disease, family, and social factors with quality of life (QoL) in patients with two common types of chronic mental illness (CMI) living in Kaohsiung City, Taiwan. Methods: Using a convenience sample and a cross-sectional design, 714 patients (50.1% male, 49.9% female) with CMI (72.1% schizophrenia and 27.9% affective disorder) and their caregivers were recruited. Demographic information was collected via the following questionnaires: 12-Item Short-Form Health Survey (SF-12), five-item Brief Symptom Rating Scale (BSRS-5), Caregiver Burden Scale, and Clinical Global Impressions (CGI-S) Scale. Pearson correlations and hierarchical regression analyses were used to predict QoL. Results: Disease factors accounted for 17-50% of the change in variance. Predictors of low mental subscale scores included the following: high psychological distress and high family burden as well as a history of suicide attempts, negative caregiver attitudes, and living away from home. Disease factors also explained the greatest variance in the physical subscales. Predictors of low physical subscale scores included the following: high psychological distress, age, unemployment, a history of suicide attempts, high family burden, and living alone. Conclusions: Disease factors were the most important predictors of QoL in patients with CMI. Family factors were more important than social factors on the mental subscales. Differential relationships were also found for the other two dimensions. Together, these results indicate that a wide range of factors improve the QoL in patients with CMI.Psychiatry and Clinical Neurosciences 09/2012; 66(6):482-90. · 2.04 Impact Factor