Increased neural response to trauma scripts in posttraumatic stress disorder following paroxetine treatment: A pilot study.

Neuroimaging studies of individuals with posttraumatic stress disorder (PTSD) have revealed altered patterns of activity in medial prefrontal brain regions, including the anterior cingulate cortex (ACC), an area implicated in affect regulation. Selective serotonin reuptake inhibitors (SSRIs) have been shown to effectively treat PTSD symptoms, but there remains a lack of functional neuroimaging research examining the effects of psychopharmacological treatment on brain function in PTSD. The purpose of this pilot study was to assess the effects of the SSRI paroxetine on neural responses to traumatic memories in a small sample of patients with PTSD, as measured with PET imaging; we hypothesized that paroxetine treatment would be associated with increased regional cerebral blood flow (rCBF) in the medial prefrontal cortex. Thirteen participants with PTSD were given controlled-release paroxetine (paroxetine CR) or placebo in a randomized, double-blind fashion for 12 weeks. Participants underwent brain imaging using positron emission tomography (PET) before and at the end of treatment in conjunction with exposure to neutral scripts and personalized trauma scripts. Participants treated with paroxetine CR and placebo both exhibited significantly increased rCBF in the ACC during trauma versus neutral script presentations; however, we noted an increase in function in the orbitofrontal cortex (OFC) in paroxetine-treated (but not placebo-treated) participants. Participants in both groups showed decreases in overall PTSD symptomatology following treatment; paroxetine-treated participants showed a slightly greater percentage decrease in symptoms. These preliminary findings indicate that increased ACC function represents a nonspecific response to treatment, whereas increased OFC function is specifically associated with paroxetine treatment in PTSD. These pilot data reveal putative mechanisms for SSRI treatment in PTSD and substantiate the need for large-scale placebo-controlled studies investigating these effects.

Neuropsychological functioning in patients with posttraumatic stress disorder following short-term paroxetine treatment.

UNLABELLED: A previous study found improvements in verbal declarative memory in patients with Posttraumatic Stress Disorder (PTSD) following one year of open-label paroxetine treatment. The purpose of the present study was to replicate prior findings and to extend the previous study by comparing the effects of paroxetine versus placebo on cognition in patients with PTSD. METHODS: Eighteen participants with PTSD underwent assessment of neuropsychological function, following which they were randomized to receive controlled-release (CR) paroxetine or placebo, given in a variable dose in a double- blind manner for three months. Neuropsychological testing was then repeated. Subjects who had received placebo were then treated with open-label paroxetine CR and re-assessed. RESULTS: Paroxetine CR treatment resulted in a significant increase in verbal declarative memory function in the group as a whole, as measured by the Wechsler Memory Scale-Revised, the Selective Reminding Test, and novel paragraph recall, and explicit recall of neutral words. Although we found patterns of improved test performance with paroxetine versus placebo treatment, these differences were not statistically significant. CONCLUSION: These findings replicate an earlier finding that open label treatment with paroxetine CR is associated with improvements in verbal declarative memory function. The current study did not show a statistically significant difference between the effects of paroxetine and placebo on memory function, which may in part be related to our small sample size.

Depressive symptoms and heart rate variability: evidence for a shared genetic substrate in a study of twins.

OBJECTIVE: To clarify the relationship between depression and heart rate variability (HRV) in a sample of twins. Reduced HRV, a measure of autonomic dysfunction, has been linked to depression but many studies have inadequately controlled for familial and environmental factors. Furthermore, little is known about whether depression and HRV share common genetic pathways. METHODS: We performed power spectral analysis on 24-hour ambulatory electrocardiograms in 288 middle-aged male twins. Log-normalized ultra low, very low, low, high frequency, and total power were calculated. A lifetime history of major depressive disorder (MDD) was determined, using the Structured Clinical Interview for Psychiatry Disorders, and current depressive symptoms were measured with the Beck Depression Inventory. Mixed-effect regression models were used to account for intrapair variability and estimate within-pair effects at the same time controlling for potential confounders. RESULTS: Both current depressive symptoms and a history of MDD were significantly associated with lower HRV. There was a graded effect, and power in each frequency band was 29% to 36% lower in the lowest band compared with the highest BDI category. All HRV measures except high frequency remained significantly associated with current depressive symptoms in multivariable analysis, but not with lifetime history of MDD. When analyses were stratified by zygosity, a significant within-pair association between BDI score and HRV was found in the dizygotic but not in the monozygotic twins, suggesting a genetic influence on the association. CONCLUSIONS: A shared, genetically influenced biological pathway underlies the association between depression and lower HRV. These two phenotypes may be the expression of a generalized neurobiological perturbation.

Association of major depressive disorder with serum myeloperoxidase and other markers of inflammation: a twin study.

BACKGROUND: Major depressive disorder (MDD) has been linked to inflammation, but this association may be due to common precursors to both depression and inflammation. Myeloperoxidase (MPO) is an inflammatory enzyme produced by activated leukocytes that predicts risk of coronary heart disease. We sought to examine whether MPO and other markers of inflammation are associated with MDD and whether the association is confounded by genetic or other shared familial factors. METHODS: We examined 178 monozygotic and dizygotic middle-aged male twin pairs. We assessed MDD with the Structured Clinical Interview for DSM-IV. Blood markers of inflammation included MPO, interleukin-6, white blood cell count, C-reactive protein, tumor necrosis factor (TNF)-alpha, the TNF-alpha soluble receptor II, and fibrinogen. Analyses were conducted in the overall sample and among 67 twin pairs discordant for MDD using mixed effects regression. RESULTS: Twins with a history of MDD had 32% higher levels of MPO (p < .0001); this difference persisted after adjusting for other risk factors. Among dizygotic MDD-discordant twin pairs, twins with MDD had 77% higher MPO than their brothers without MDD, after adjusting for other factors (p < .0001). In contrast, no significant association was found in monozygotic twins (p = .13). Similar, but weaker, associations were found between MDD and other inflammatory biomarkers. CONCLUSIONS: Myeloperoxidase is a useful biomarker of immune activation in MDD. However, the association between inflammation and MDD is largely due to common genetic liability. Our results are consistent with the hypothesis that genes promoting inflammation are involved in the pathogenesis of MDD.