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There a lack of consistent neuroimaging data on specific phobia (SP) and a need to assess volumetric and metabolic differences in structures implicated in this condition. The aim of this study is investigate possible metabolic (via 1H MRS) and cortical thickness abnormalities in spider-phobic patients compared to healthy volunteers. Participants were recruited via public advertisement and underwent clinical evaluations and MRI scans. The study started in 2010 and the investigators involved were not blind in respect to patient groupings. The study was conducted at the Ribeirao Preto Medical School University Hospital of the University of Sao Paulo, Brazil. Patients with spider phobia (n=19) were matched to 17 healthy volunteers with respect to age, education and socio-economic status. The spider SP group fulfilled the diagnostic criteria for spider phobia according to the Structured Clinical Interview for DSM-IV. None of the participants had a history of neurological, psychiatric or other relevant organic diseases, use of prescribed psychotropic medication or substance abuse. All imaging and spectroscopy data were collected with a 3 T MRI scanner equipped with 25 mT gradient coils in 30-minute scans. The Freesurfer image analysis package and LC Model software were used to analyze data. The hypothesis being tested was formulated before the data collection (neural correlates of SP would include the amygdala, insula, anterior cingulate gyrus and others). The results indicated the absence of metabolic alterations, but thinning of the right anterior cingulate cortex (ACC) in the SP group when compared to the healthy control group (mean cortical thickness±SD: SP=2.11±0.45 mm; HC=2.16±0.42 mm; t (34)=3.19, p=0.001 [−35.45, 71.00, −23.82]). In spectroscopy, the ratios between N-acetylaspartate and creatine and choline levels were measured. No significant effect or correlation was found between MRS metabolites and scores in the Spider Phobia Questionnaire and Beck Anxiety Inventory (p>0.05). The ACC is known to be related to the cognitive processing of fear and anxiety and to be linked with the conditioning circuit. The MRS findings are preliminary and need more studies. The finding of reduced ACC thickness in SP is in agreement with evidence from previous functional neuroimaging studies and highlights the importance of this brain area in the pathophysiology of SP.

Body stability is controlled by the postural system and can be affected by fear and anxiety. Few studies have addressed freezing posture in psychiatric disorders. The purpose of the present study was to assess posturographic behavior in 30 patients with social anxiety disorder (SAD) and 35 without SAD during presentation of blocks of pictures with different valences. Neutral images consisted of objects taken from a catalog of pictures, negative images were mutilation pictures and anxiogenic images were related to situations regarding SAD fears. While participants were standing on a force platform, similar to a balance, displacement of the center of pressure in the mediolateral and anteroposterior directions was measured. We found that the SAD group exhibited a lower sway area and a lower velocity of sway throughout the experiment independent of the visual stimuli, in which the phobic pictures, a stimulus associated with a defense response, were unable to evoke a significantly more rigid posture than the others. We hypothesize that patients with SAD when entering in a situation of exposure, from the moment the pictures are presented, tend to move less than controls, remaining this way until the experiment ends. This discrete body manifestation can provide additional data to the characterization of SAD and its differentiation from other anxiety disorders, especially in situations regarding facing fear.

BACKGROUND: It has been suggested that individuals with social anxiety disorder (SAD) are exaggeratedly concerned about approval and disapproval by others. Therefore, we assessed the recognition of facial expressions by individuals with SAD, in an attempt to overcome the limitations of previous studies. METHODS: The sample was formed by 231 individuals (78 SAD patients and 153 healthy controls). All individuals were treatment naive, aged 18-30years and with similar socioeconomic level. Participants judged which emotion (happiness, sadness, disgust, anger, fear, and surprise) was presented in the facial expression of stimuli displayed on a computer screen. The stimuli were manipulated in order to depict different emotional intensities, with the initial image being a neutral face (0%) and, as the individual moved on across images, the expressions increased their emotional intensity until reaching the total emotion (100%). The time, accuracy, and intensity necessary to perform judgments were evaluated. RESULTS: The groups did not show statistically significant differences in respect to the number of correct judgments or to the time necessary to respond. However, women with SAD required less emotional intensity to recognize faces displaying fear (p=0.002), sadness (p=0.033) and happiness (p=0.002), with no significant differences for the other emotions or men with SAD. CONCLUSIONS: The findings suggest that women with SAD are hypersensitive to threat-related and approval-related social cues. Future studies investigating the neural basis of the impaired processing of facial emotion in SAD using functional neuroimaging would be desirable and opportune. Language: en