Background: Posttraumatic stress disorder (PTSD) is an anxiety disorder that can develop after one or more traumatic events causing extreme stress or grave physical harm. The neurokinin-1 (NK1) receptor is the primary receptor for substance P (SP); a neuropeptide suggested being involved in anxiety and depression. The present study investigated differences in NK1-receptor availability between PTSD patients and healthy controls, using positron emission tomography (PET). Methods: Eleven male refugee patients (age: 41±10) with DSM-IV defined PTSD and nine healthy male control subjects (age: 33±10) were investigated using the PET-tracer [11C]GR205171, supplied by Uppsala Imanet. GR205171 is a highly selective NK1-receptor antagonist. Scans were performed during 60 minutes in the resting state. Parametric images were generated using the graphical reference Patlak method assuming irreversible binding of [11C]GR205171 from 20-60 minutes and having cerebellum as reference region. Exploratory whole brain analyses were performed using the statistical parametric mapping (SPM2) software. Results: PTSD patients had lower [11C]GR205171 binding compared to controls, in frontal cortical clusters encompassing bilaterally insula and left Brodmann area 11, reflecting lower NK1-receptor availability. No areas were found in which PTSD patients had higher [11C]GR205171 binding. Conclusions: This is the first study reporting differences in NK1-receptor availability in PTSD patients relative to controls. A tentative conclusion is that PTSD patients have a down regulation of the NK1-receptor system, which could be either a risk factor or due to emotional trauma processing.

This public mental health study highlights the interactions among social determinants and resilience on mental health, PTSD and acculturation among Iraqi refugees in Sweden 2012-2013.

Objectives: The study aims to understand participants' health, resilience and acculturation, paying specific attention to gender differences.

Design: The study, using a convenience sampling survey design (N = 4010, 53.2% men), included measures on social determinants, general health, coping, CD-RISC, selected questions from the EMIC, PC-PTSD, and acculturation.

Results: Gender differences and reported differences between life experiences in Iraq and Sweden were strong. In Sweden, religious activity was more widespread among women, whereas activity reflecting religion and spirituality as a coping mechanism decreased significantly among men. A sense of belonging both to a Swedish and an Iraqi ethnic identity was frequent. Positive self-evaluation in personal and social areas and goals in life was strong. The strongest perceived source of social support was from parents and siblings, while support from authorities generally was perceived as low. Self-rated health was high and the incidence of PTSD was low. A clear majority identified multiple social determinants contributing to mental health problems. Social or situational and emotional or developmental explanations were the most common. In general, resilience (as measured with CD-RISC) was low, with women's scores lower than that of men.

Conclusions: Vulnerability manifested itself in unemployment after a long period in Sweden, weak social networks outside the family, unsupportive authorities, gender differences in acculturation, and women showing more mental health problems. Though low socially determined personal scores of resilience were found, we also identified a strong level of resilience, when using a culture-sensitive approach and appraising resilience as expressed in coping, meaning, and goals in life. Clinicians need to be aware of the risks of poorer mental health among refugees in general and women in particular, although mental health problems should not be presumed in the individual patient. Instead clinicians need to find ways of exploring the cultural and social worlds and needs of refugee patients. Authorities need to address the described post-migration problems and unmet needs of social support, together comprising the well-established area of the social determinants of health.

We report positron emission tomographic measurements of regional cerebral blood flow (rCBF) in a male patient with war and torture related post-traumatic stress disorder (PTSD) during symptom provocation. The subject was exposed to war related sounds before and after treatment with a selective serotonin reuptake inhibitor (SSRI; Fluoxetine; Fontex((R))). Therapy reduced PTSD symptoms, provoked anxiety and heart rate. Before treatment trauma reminders resulted in decreased rCBF in the insula, prefrontal, and inferior frontal cortices. Increased activity was evident in the cerebellum, precuneus and supplementary motor cortex. This was normalized after SSRI administration. Prefrontal and cingulate rCBF correlated with heart rate. Hence, the anxiolytic effect of SSRI for PTSD could be mediated by prefrontal and paralimbic cortices. Data suggest that SSRI treatment normalize provocation induced rCBF alterations in areas involved in memory, emotion, attention and motor-control.

The brain serotonergic system is colocalized and interacts with the neuropeptidergic substance P/neurokinin-1 (SP/NK1) system. Both these neurochemical systems have independently been implicated in stress and anxiety, but interactions between them might be crucial for human anxiety conditions. Here, we examined the serotonin and substance P/neurokinin-1 (SP/NK1) systems individually as well as their overlapping expression in 16 patients with posttraumatic stress disorder (PTSD) and 16 healthy controls. Participants were imaged with the highly selective radiotracers [(11)C]-3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile (DASB) and [(11)C]GR205171 assessing serotonin transporter (SERT) and NK1 receptor availability, respectively. Voxel-wise analyses in the amygdala, our a priori-defined region of interest, revealed increased number of NK1 receptors, but not SERT in the PTSD group. Symptom severity, as indexed by the Clinician-administered PTSD Scale, was negatively related to SERT availability in the amygdala, and NK1 receptor levels moderated this relationship. Exploratory, voxel-wise whole-brain analyses revealed increased SERT availability in the precentral gyrus and posterior cingulate cortex of PTSD patients. Patients, relative to controls, displayed lower degree of overlapping expression between SERT and NK1 receptors in the putamen, thalamus, insula and lateral orbitofrontal gyrus, lower overlap being associated with higher PTSD symptom severity. Expression overlap also explained more of the symptomatology than did either system individually, underscoring the importance of taking interactions between the neurochemical systems into account. Thus, our results suggest that aberrant serotonergic-SP/NK1 couplings contribute to the pathophysiology of PTSD and, consequently, that normalization of these couplings may be therapeutically important.

SUMMARY: Patients with combat-related posttraumatic stress disorder (PTSD) show altered cognitive and affective processing and symptomatic responding following exposure to trauma reminders. Previous symptom provocation studies using brain imaging have involved Vietnam veterans. In this study neural correlates were investigated in patients with PTSD resulting from trauma in more recent war zones. (15)Oxygen water and positron emission tomography were used to measure regional cerebral blood flow (rCBF) in patients with war- and combat-related chronic PTSD during exposure to combat and neutral sounds. Self-reports and heart rate confirmed symptomatic responding during traumatic stimulation. The war-related condition, as compared to the neutral, increased rCBF in the right sensorimotor areas (Brodmann areas 4/6), extending into the primary sensory cortex (areas 1/2/3), and the cerebellar vermis. RCBF also increased in the right amygdala and in the periaqueductal gray matter adjacent to the pons. During provocation rCBF was lowered in the right retrosplenial cortex (areas 26/29/30 extending into area 23). Symptom provocation in PTSD promote sensorimotor, amygdaloid and midbrain activation. We conclude that perceptually induced symptom activation in PTSD is associated with an emotionally determined motor preparation and propose that subcortically initiated rather than cortically controlled memory mechanisms determine this pattern.