Impaired reward responsiveness in schizophrenia.

BACKGROUND: Anhedonia is a core negative symptom of schizophrenia. Schizophrenia patients report largely intact pleasure in consuming rewards, but have impairments in generating motivated behavior to pursue rewards, and show reduced fMRI activation of the reward pathway during presentation of rewarded stimuli. A computer based task measuring the development of a response bias in favor of rewarded stimuli permits assessment of reward-induced motivation. We hypothesized that subjects with schizophrenia would be impaired on this task. METHODS: 58 schizophrenia subjects (SCZ) and 52 healthy controls (CON) were studied with a signal detection task to assess reward responsiveness. In multiple trials over three blocks subjects were asked to correctly identify two stimuli that were paired with unequal chance of monetary reward. The critical outcome variable was response bias, the development of a greater percent correct identification of the stimulus that was rewarded more often. RESULTS: An ANOVA on response bias with Block as a repeated-measures factor and Diagnosis as a between-group factor indicated that SCZ subjects achieved a lower bias to rewarded stimuli than CON subjects (F(1,105)=8.82, p=0.004, η2=0.078). Post hoc tests indicated that SCZ subjects had significantly impaired bias in Block 1 (p=0.002) and Block 2 (p=0.05), indicating that SCZ were slower to achieve normal levels of bias during the session. CONCLUSIONS: SCZ subjects were slower to develop response bias to rewarded stimuli than CON subjects. This finding is consonant with the hypothesis that people with schizophrenia have a blunted capacity to modify behavior in response to reward.

Predictors of Calf Arterial Compliance in Male Veterans With Psychiatric Diagnoses.

BACKGROUND: Peripheral arterial compliance (PAC) is a measure of the ability of the vascular tree to dilate in response to a pressure wave. Reduced PAC is seen in patients with psychiatric diagnoses and has been associated with increased risk for stroke, myocardial infarction, and mortality. The objective of this pilot study was to identify predictors of reduced PAC in subjects with psychiatric diagnoses. METHODS: Male psychiatric subjects (N = 77) were studied in a cross-sectional study of medication effects on PAC conducted from August 2005 to February 2010. Calf and thigh compliance were modeled in separate linear regressions. The models were adjusted for age, race, smoking status, presence or absence of the metabolic syndrome, current treatment with a statin, diagnosis of schizophrenia or schizoaffective disorder, current antipsychotic treatment, and body mass index (BMI). RESULTS: Of the 77 subjects (mean ± SD age of 53.7 ± 8.8 years), 41 were white, 36 were black, and 27 were diagnosed with schizophrenia or schizoaffective disorder (DSM-IV criteria). Fifty participants were being treated with an antipsychotic medication, while the remaining 27 were off of antipsychotics for at least 2 months. Our model explained 27% of the variance in calf compliance. Black subjects had reduced calf compliance compared to white subjects (P = .02). Having metabolic syndrome was associated with reduced PAC at a trend level (P < .08), and BMI (P = .004) and BMI2 (P = .011) were significant predictors of calf compliance. Schizophrenia versus other psychiatric diagnoses and antipsychotic treatment were not significantly associated with calf compliance. CONCLUSIONS: In this pilot study, significant predictors of calf compliance were race (black vs white) and BMI. PAC is a noninvasive measure that may be a predictor of cardiovascular risk in psychiatric patients. The reduced PAC seen in patients with psychiatric diagnoses does not appear to be directly related to their diagnosis or antipsychotic treatment but rather to other characteristics inherent to the subject. Future studies are warranted to better understand the pathophysiology of PAC including but not limited to inflammation in psychiatric patients.

Reduced arterial compliance in patients with psychiatric diagnoses.

BACKGROUND: Peripheral arterial compliance is a measure of elasticity of the arteries that has been found to be a robust predictor of prevalent arteriosclerosis as well as incident stroke and myocardial infarction. Psychiatric diagnoses and second generation antipsychotics may contribute to cardiovascular risk and stroke, but effects on peripheral arterial compliance are unknown. This study compared peripheral arterial compliance in healthy male controls to male patients with psychiatric diagnoses who were treated with quetiapine or risperidone or off antipsychotics at time of testing. METHODS: The groups consisted of 63 patients with mental illness taking quetiapine, risperidone, or no antipsychotics. There were 111 males in the control group. Mean thigh and calf arterial compliance among four groups were compared by ANCOVA, adjusting for body mass index and Framingham Risk Score. All patients were also compared to the control group. Compliance was measured with a computerized plethysmography device. RESULTS: Patients (n=63) had significantly lower arterial compliance in both thigh and calf than the controls. Arterial compliance in the calf was significantly lower in the subgroups of quetiapine (n=16) and risperidone (n=19) treated, and in unmedicated (n=28) patients than in controls. In the thigh, patients taking either quetiapine or risperidone had significantly lower arterial compliance than controls. These subgroups did not differ from each other in arterial compliance. CONCLUSION: The presence of psychiatric diagnoses is associated with reduced arterial compliance. A large study may be required to measure any specific affects of antipsychotics such as quetiapine and risperidone on compliance compared to controls.

10-year review of knee dislocations: is arteriography always necessary?

BACKGROUND: Historically, arteriography has been used routinely in patients with knee dislocations. Recently, selectivity based on physical examination (PE) has emerged. Critics cite limited clinical evidence. We sought to determine whether PE accurately confirms or excludes surgically significant vascular injuries associated with knee dislocations. METHODS: We conducted an institutional review board-approved retrospective review of patients admitted at a university-based Level I trauma center with knee dislocations from January 1, 1993, to December 31, 2002. Thirty-nine patients (28 male patients and 11 female patients; average age, 42.8 years) had 39 dislocations (27 left and 12 right, 26 posterior and 13 anterior). Most patients (n = 25) were involved in motor vehicle crashes. All patients underwent arteriography. RESULTS: Of the 20 normal arteriograms, all had normal PE. Of the 19 abnormal arteriograms, 8 had a normal PE and 11 were abnormal. Within this subgroup, none of the 8 with normal PE required surgery, whereas 7 of the 11 with abnormal PE required surgery. None of the nonoperative patients had vascular complications during the hospital stay. Sensitivity and specificity were 100% for PE on surgically significant vascular injury. CONCLUSION: Routine arteriography is unnecessary in patients with a normal PE after reduction of the knee dislocation.