Margaret T. Susce

OBJECTIVE: The cytochrome P450 2D6 (CYP2D6) enzyme metabolizes risperidone. CYP2D6 poor metabolizers have no CYP2D6 activity (7% of whites and 1%-2% of other races). This study tested whether the CYP2D6 poor metabolizer phenotype was associated with adverse drug reactions (ADRs) and discontinuation due to ADRs. METHOD: Adult inpatients and outpatients were recruited from July 2000 to March 2003 including (1) 325 who were stabilized on risperidone therapy and classified as either expressing moderate-to-marked ADRs (22%, 73/325) or not (78%, 252/325) and (2) 212 who discontinued risperidone and were classified as discontinued due to ADRs (38%, 81/212) or for other reasons (62%, 131/212). Genetic tests were performed by allele-specific polymerase chain reaction and/or by the AmpliChip CYP450 microarray system for up to 34 separate CYP2D6 alleles. Two logistic regression models with dependent variables (moderate-to-marked ADRs while taking risperidone and risperidone discontinuation due to ADRs) were evaluated with respect to the CYP2D6 phenotype. RESULTS: The odds ratios (ORs) and 95% confidence intervals (CIs) for the CYP2D6 poor metabolizer phenotype in the univariate analyses and after correcting for clinical variables were (1) OR = 3.1 (CI = 1.4 to 7.0) and 3.4 (CI = 1.5 to 8.0) for moderate-to-marked ADRs on risperidone and (2) OR = 3.0 (CI = 0.85 to 10.6) and 6.0 (CI = 1.4 to 25.4) for discontinuation due to ADRs. CONCLUSIONS: The CYP2D6 poor metabolizer phenotype appears to be associated with risperidone ADRs and discontinuation due to ADRs; however, this finding requires further study in larger patient populations. The CYP3A5 and p-glycoprotein exon 21 and 26 genotypes were not significantly associated with risperidone response.

OBJECTIVES: This study compared the prevalence of tobacco smoking behaviors in patients with bipolar disorder with normal and psychiatric (schizophrenia and major depression) controls. The main goal was to establish that bipolar patients smoke more than normal controls. Differences with psychiatric controls were explored. METHODS: Samples of 424 patients (99 bipolar, 258 schizophrenia and 67 major depression) and 402 volunteer controls were collected in Central Kentucky. Smoking data for Kentucky's general population were available. Odds ratios (ORs) and their 95% confidence intervals (CIs) were used to establish the strength of associations. Logistic regression was used to adjust ORs for confounding variables. RESULTS: Using epidemiological definitions of smoking behaviors and the general population as controls provided bipolar disorder unadjusted ORs of 5.0 (95% CI: 3.3-7.8) for current cigarette smoking, 2.6 (95% CI: 1.7-4.4) for ever cigarette smoking, and 0.13 (95% CI: 0.03-0.24) for smoking cessation. Using a clinical definition and volunteers as controls provided respective bipolar disorder adjusted ORs of 7.3 (95% CI: 4.3-12.4), 4.0 (95% CI: 2.4-6.7), and 0.15 (95% CI: 0.06-0.36). Prevalences of current daily smoking for patients with major depression, bipolar disorder, and schizophrenia were 57%, 66%, and 74%, respectively. CONCLUSIONS: Bipolar disorder was associated with significantly higher prevalences of tobacco smoking behaviors compared with the general population or volunteer controls, independently of the definition used. It is possible that smoking behaviors in bipolar disorder may have intermediate prevalences between major depression and schizophrenia, but larger samples or a combination of multiple studies (meta-analysis) will be needed to establish whether this hypothesis is correct.

BACKGROUND: This naturalistic cross-sectional survey of patients with severe mental illnesses explores the association between important variables and obesity, extreme obesity, diabetes mellitus type 2, hypertension, and hyperlipidemia in the clinical environment. METHOD: Weight and height were obtained from 560 patients with severe mental illnesses (including DSM-IV schizophrenia, schizoaffective disorder, bipolar disorder, and major depressive disorder) at central Kentucky inpatient and outpatient facilities to estimate their body mass index (BMI). Chart diagnoses of diabetes mellitus, hypertension, and hyperlipidemia were obtained. RESULTS: When comparing the patients with severe mental illnesses with Kentucky adults from the general population, the odds ratio (OR) of obesity (BMI > or = 30 kg/m(2)) was 2.6 (95% confidence interval [CI] = 2.2 to 3.0), and the OR of diabetes mellitus was 2.9 (95% CI = 2.3 to 3.6). Female gender, African American race, early start of psychiatric medication, and long psychiatric medication duration were significantly associated with obesity. Current alcohol and nicotine use exhibited significant ORs of obesity lower than 1, particularly in males. Obesity was closely associated with hypertension, type 2 diabetes mellitus, and hyperlipidemia. These complications were closely associated with each other and may indicate a further progression of obesity after aging. CONCLUSIONS: These results suggest a complex pattern of variables that may influence the development of obesity and its complications in patients with severe mental illnesses, but they need replication. The major factors associated with obesity appear to be a long-term illness or treatment duration and substance use. The former may be more important in females, while the latter may be more important in males. Clinical diagnoses (schizophrenic or mood disorders) or current treatment did not appear to be fundamental factors.