Temporal lobe involvement in panic disorder: results of a replication study

Depersonalization and individualism: the effect of culture on symptom profiles in panic disorder

It has been proposed that highly individualistic cultures confer vulnerability to depersonalization. To test this idea, we carried out a comprehensive systematic review of published empirical studies on panic disorder, which reported the frequency of depersonalization/derealization during panic attacks. It was predicted that the frequency of depersonalization would be higher in Western cultures and that a significant correlation would be found between the frequency of depersonalization and individualism scores of the participant countries. As predicted, the frequency of depersonalization during panic was significantly lower in nonwestern countries. There was also a significant correlation between frequency of depersonalization and Individualism (rho = 0.68, p < 0.0001), and between fears of losing control (rho = 0.57, p = 0.005) and individualism. These findings are interpreted in light of recent studies suggesting that individualistic cultures are characterized by hypersensitivity to threat and by an external locus of control. Two features may be relevant in the genesis of depersonalization.

Depersonalization: neurobiological perspectives

Depersonalization remains a fascinating and obscure clinical phenomenon. In addition to earlier Jacksonian neurobiological adumbrations, and conventional psychodynamic accounts, views started to be expressed in the 1930s that depersonalization might be a vestigial form of behavior, and since the 1960s that it might be a phenomenon related to the temporal lobe. Recent advances in the neurobiology of the limbic system, and the application of Geschwind's concept of disconnection in the corticolimbic system, have opened the possibility of developing testable models. This paper includes a review of these ideas and of the clinical features of depersonalization, particularly of its emotional changes, suggesting that they are important for the neurobiological understanding of depersonalization. It also draws attention to clinical similarities between the experiential narratives produced by patients suffering from depersonalization and those with corticolimbic disconnections. On the basis of this, a new model is proposed according to which the state of increased alertness observed in depersonalization results from an activation of prefrontal attentional systems (right dorsolateral prefrontal cortex) and reciprocal inhibition of the anterior cingulate, leading to experiences of "mind emptiness" and "indifference to pain" often seen in depersonalization. On the other hand, a left-sided prefrontal mechanism would inhibit the amygdala resulting in dampened autonomic output, hypoemotionality, and lack of emotional coloring that would in turn, be reported as feelings of "unreality or detachment."

Temporal lobe electroencephalogram power modifications during olfactory stimulation in HIV-infected patients

Evidence derived from studies concerning brain metabolism and brain electrical activity suggests that temporal lobe functioning is impaired in the course of HIV infection. To test the hypothesis of temporal lobe dysfunction in HIV infection, we utilized computerized electroencephalogram (EEG) analysis to evaluate temporal lobe EEG power modifications induced by olfactory stimulation in 10 HIV-infected patients as compared with 10 seronegative control subjects. Our findings show that HIV-infected patients respond to olfactory stimulation with an increase in temporal lobe slow electrical activity (theta EEG power), whereas control subjects show a decrease in the same activity. The theta EEG power increase during olfactory stimulation in HIV-infected patients can be interpreted as a paradoxical response of the deep temporal regions to specific procedures, supporting the hypothesis of temporal lobe dysfunction in HIV infection.