Varenicline is an effective and increasingly prescribed drug for smoking cessation, but has been associated with depressive symptoms and suicidal behavior. However, it remains unclear whether those changes in mood and behavior are directly related to varenicline use, or caused by smoking cessation itself or reflects depression and suicidality rates in smokers, independent of treatment. To investigate the influence of varenicline on mood and behavior independent of smoking and smoking cessation, we assessed the effects of varenicline on emotional processing (a biomarker of depressogenic effects), emotion-potentiated startle reactivity, impulsivity (linked with suicidal behavior), and cognitive performance in non-smoking subjects. We used a randomized, double-blind design, in which we administered varenicline or placebo to healthy subjects over 7 days (0.5 mg/day first 3 days, then 1 mg/day). Cognitive and emotional processing was assessed by a battery of computerized tasks and recording of emotion-potentiated startle response. A total of 41 subjects were randomized, with 38 subjects included in the analysis. The varenicline group did not differ from placebo in terms of negative biases in emotional processing or mood. However, compared with placebo, the varenicline group scored higher on working and declarative memory. In conclusion, short-term varenicline use did not influence negative biases in emotional processing or impulsivity in non-smoking subjects, thereby not supporting direct depressogenic or suicidal risk behavior-inducing effects. In contrast, varenicline may have cognitive-enhancing effects.

Diazepam administration increases functional connectivity in areas of emotional processing independent of any task. Diazepam also enhanced functional connectivity in the medial visual system, which is a brain region rich in GABAA receptors, and shows high binding of GABAergic drugs. These increases in functional connectivity are characteristic of CNS depressants.

Background and Objectives:Diffusion tensor imaging (DTI) networks integrate damage from a variety of pathological processes in cerebral small vessel disease (SVD) and may be a sensitive marker to detect treatment effects. We determined whether brain network analysis could detect treatment effects in the PRESERVE trial dataset, in which intensive versus standard blood pressure (BP) lowering was compared. The primary endpoint of DTI had not shown treatment differences.Methods:Subjects with lacunar stroke were randomised to standard (systolic 130-140 mmHg), or intensive (systolic </= 125 mmHg) BP lowering and followed for 2-years with MRI at baseline and at 2 years. Graph-theory based metrics were derived from DTI data to produce a measure of network integrity weighted global efficiency, and compared to individual MRI markers of DTI, brain volume and white matter hyperintensities.Results:Data were available in 82 subjects; standard n=40 (mean age 66.3±1.5), intensive n=42 (69.6±1.0). Mean (SD) systolic blood pressure was reduced by 13(14) and 23(23) mmHg in the standard and intensive groups respectively (P<0.001 between groups). Significant differences in diffusion network metrics were found, with improved network integrity (weighted global efficiency, P=0.002) seen with intensive BP lowering. In contrast there were no significant differences in individual MRI markers including DTI histogram metrics, brain volume or white matter hyperintensities.Discussion:Brain network analysis may be a sensitive surrogate marker in trials in small vessel disease. This work suggests that measures of brain network efficiency may be more sensitive to the effects of blood pressure control treatment than conventional DTI metrics.Trial Registration Information:The trial is registered with the ISRCTN Registry (ISRCTN37694103; //doi.org/10.1186/ISRCTN37694103) and the NIHR Clinical Research Network (CRN 10962; //public-odp.nihr.ac.uk/QvAJAXZfc/opendoc.htm?document=crncc_users%5Cfind%20a%20clinical%20research%20study.qvw&lang=en-US&host=QVS%40crn-prod-odp-pu&anonymous=true)Classification of Evidence:This study provides Class II evidence that intensive BP lowering in patients with small vessel disease results in improved brain network function when assessed by DTI based brain network metrics.