Increased blood mercury levels in patients with Alzheimer's disease.

Alzheimer's disease (AD) is a common neurodegenerative disorder that leads to dementia and death. In addition to several genetic parameters, various environmental factors may influence the risk of getting AD. In order to test whether blood levels of the heavy metal mercury are increased in AD, we measured blood mercury concentrations in AD patients (n = 33), and compared them to age-matched control patients with major depression (MD) (n = 45), as well as to an additional control group of patients with various non-psychiatric disorders (n = 65). Blood mercury levels were more than two-fold higher in AD patients as compared to both control groups (p = 0.0005, and p = 0.0000, respectively). In early onset AD patients (n = 13), blood mercury levels were almost three-fold higher as compared to controls (p = 0.0002, and p = 0.0000, respectively). These increases were unrelated to the patients' dental status. Linear regression analysis of blood mercury concentrations and CSF levels of amyloid beta-peptide (A beta) revealed a significant correlation of these measures in AD patients (n = 15, r = 0.7440, p = 0.0015, Pearson type of correlation). These results demonstrate elevated blood levels of mercury in AD, and they suggest that this increase of mercury levels is associated with high CSF levels of A beta, whereas tau levels were unrelated. Possible explanations of increased blood mercury levels in AD include yet unidentified environmental sources or release from brain tissue with the advance in neuronal death.

Course of illness in phobic postural vertigo.

Forty-two patients with phobic postural vertigo took part in a neurological and psychiatric follow-up study. During the follow-up time of about 2.5 years the neurological diagnosis remained stable (41 of 42 patients). PPV can be assigned to various psychiatric categories according to DSM-III-R. Although an association of PPV with anxiety disorders is evident, not all patients present with symptoms of anxiety or panic during attacks of vertigo. However most patients develop a disabling "phobic-avoidance pattern" with recurrent attacks. Important psychosocial stressors can be identified at the onset of the condition. Motives of secondary gain have also to be taken into consideration. The course of illness varies depending on the neurological syndrome of vertigo, on the one hand, and concomitant psychopathological syndromes, on the other. Despite a considerable rate of improvement in vertigo complaints (79%), the group of patients with phobic postural vertigo as a whole presented with significant psychological problems at follow-up term (74%), requiring specific psychiatric and/or psychotherapeutic interventions. Dependent or avoidant personality, and hypochondria were prognostic of a more negative course of illness.