Divergent relationship of depression severity to social reward responses among patients with bipolar versus unipolar depression.

Neuroimaging studies of mood disorders demonstrate abnormalities in brain regions implicated in reward processing. However, there is a paucity of research investigating how social rewards affect reward circuit activity in these disorders. Here, we evaluated the relationship of both diagnostic category and dimensional depression severity to reward system function in bipolar and unipolar depression. In total, 86 adults were included, including 24 patients with bipolar depression, 24 patients with unipolar depression, and 38 healthy comparison subjects. Participants completed a social reward task during 3T BOLD fMRI. On average, diagnostic groups did not differ in activation to social reward. However, greater depression severity significantly correlated with reduced bilateral ventral striatum activation to social reward in the bipolar depressed group, but not the unipolar depressed group. In addition, decreased left orbitofrontal cortical activation correlated with more severe symptoms in bipolar depression, but not unipolar depression. These differential dimensional effects resulted in a significant voxelwise group by depression severity interaction. Taken together, these results provide initial evidence that deficits in social reward processing are differentially related to depression severity in the two disorders.

Common and Dissociable Dysfunction of the Reward System in Bipolar and Unipolar Depression.

Unipolar and bipolar depressive episodes have a similar clinical presentation that suggests common dysfunction of the brain's reward system. Here, we evaluated the relationship of both dimensional depression severity and diagnostic category to reward system function in both bipolar and unipolar depression. In total, 89 adults were included, including 27 with bipolar depression, 25 with unipolar depression, and 37 healthy comparison subjects. Subjects completed both a monetary reward task and a resting-state acquisition during 3T BOLD fMRI. Across disorders, depression severity was significantly associated with reduced activation for wins compared with losses in bilateral ventral striatum, anterior cingulate cortex, posterior cingulate cortex, and right anterior insula. Resting-state connectivity within this reward network was also diminished in proportion to depression severity, most notably connectivity strength in the left ventral striatum. In addition, there were categorical differences between patient groups: resting-state connectivity at multiple reward network nodes was higher in bipolar than in unipolar depression. Reduced reward system task activation and resting-state connectivity therefore appear to be a brain phenotype that is dimensionally related to depression severity in both bipolar and unipolar depression. In contrast, categorical differences in reward system resting connectivity between unipolar and bipolar depression may reflect differential risk of mania. Reward system dysfunction thus represents a common brain mechanism with relevance that spans categories of psychiatric diagnosis.

Amotivation in schizophrenia: integrated assessment with behavioral, clinical, and imaging measures.

Motivational deficits play a central role in disability caused by schizophrenia and constitute a major unmet therapeutic need. Negative symptoms have previously been linked to hypofunction in ventral striatum (VS), a core component of brain motivation circuitry. However, it remains unclear to what extent this relationship holds for specific negative symptoms such as amotivation, and this question has not been addressed with integrated behavioral, clinical, and imaging measures. Here, 41 individuals with schizophrenia and 37 controls performed a brief, computerized progressive ratio task (PRT) that quantifies effort exerted in pursuit of monetary reward. Clinical amotivation was assessed using the recently validated Clinical Assessment Interview for Negative Symptoms (CAINS). VS function was probed during functional magnetic resonance imaging using a monetary guessing paradigm. We found that individuals with schizophrenia had diminished motivation as measured by the PRT, which significantly and selectively related to clinical amotivation as measured by the CAINS. Critically, lower PRT motivation in schizophrenia was also dimensionally related to VS hypofunction. Our results demonstrate robust dimensional associations between behavioral amotivation, clinical amotivation, and VS hypofunction in schizophrenia. Integrating behavioral measures such as the PRT will facilitate translational efforts to identify biomarkers of amotivation and to assess response to novel therapeutic interventions.

An extended validation of the ScottCare 320 ambulatory blood pressure monitor: recommendations for clinical application.

OBJECTIVES: The purpose of this study was to validate the ScottCare 320 ambulatory blood pressure monitor (ABPM) using both group-level and individual-level validation procedures. The group-level validation followed a modified protocol of the European Hypertension Society's validation protocol. The individual-level validation was conducted to ensure that the monitor is valid from both a research and clinical perspective. METHODS: Participants (n=41) had three simultaneous blood pressure (BP) measurements taken by a trained listener using a mercury column sphygmomanometer and the ScottCare ABPM, which was used to validate the monitor at the group-level and the first half of the individual-level validation (i.e. the difference between the ABPM and auscultatory means for each participant <5 mmHg). The second half of the individual-level validation occurred by examining participants' responses on diary questionnaires taken immediately following the BP measurements (i.e. can extreme or deviant BP values be explained by situational factors). RESULTS: At the group level, the ABPM passed the criteria laid out by the European Hypertension Society. At the individual level, the difference between the auscultatory and ABPM means was less than 5 mmHg for both systolic and diastolic BP for 36 participants on the initial attempt, and the remaining five on the second attempt. Furthermore, the deviant values were largely attributed to explainable causes, mainly movement. CONCLUSION: The ScottCare ABPM is a highly accurate monitor that can be considered valid at both the group and the individual level, and thus appropriate for both clinical and research use.

Can blood pressure measurements taken in the physician's office avoid the 'white coat' bias?

OBJECTIVE: Obtaining an accurate blood pressure (BP) reading is vital for diagnosing hypertension. However, BP measures taken in the physician's clinic (CBP) are subject to the 'white coat' bias. Measurements taken outside the office using ambulatory (ABP) and home (HBP) monitoring are superior predictors of cardiovascular diseases compared with CBP, but ABP remains underutilized because of the effort and expense involved. Unfortunately, HBP has limitations, including questionable device validity and patient compliance. Thus, it is important to identify feasible alternative techniques to measure BP in the office that will increase the accuracy of the diagnosis. METHODS: Auscultatory BP was measured in 249 patients in a nonclinical setting by trained technicians (NCBP); on the following day, patients were taken to their physician (CBP). They were also given an HBP monitor, and a 36 h ABP monitoring. Because ABP is considered the gold standard for prediction of cardiovascular disease, these readings were used as the criterion in a statistical model in which CBP, HBP, and NCBP were entered as predictors. The level of agreement between measurements was estimated. RESULTS: Multiple regression analysis showed that HBP and NCBP (P < 0.001) explained 94 and 87% of the variance in systolic and diastolic ABP, respectively. The agreement between NCBP and ABP was greater than that between CBP and ABP or between HBP. CONCLUSION: When ABP monitoring and HBP monitoring are not options, the NCBP at the clinic can avoid the white coat bias and therefore improve diagnosis.