Personality and risk of hospital diagnosed mental disorder: a 35 years' prospective study.

PURPOSE: The present study examined the prospective association of neuroticism, extraversion and psychoticism with risk of hospital diagnosed mental disorder, examining intelligence as a potential confounder of this association. METHODS: A total of 1118 Danish men and women completed the Eysenck personality questionnaire at the mean age of 27 years. Information on psychiatric diagnoses was obtained by linking the study population to the national Danish psychiatric registers, and risk of diagnoses associated with each personality trait was examined using multiple Cox regression in models including the three personality traits unadjusted and adjusted for intelligence. Participants with diagnosis from a psychiatric department prior to the personality assessment were excluded. RESULTS: In total, 122 participants were diagnosed with a mental disorder during follow-up. Neuroticism significantly predicted risk of anxiety-, adjustment-, personality- and alcohol and substance abuse diagnoses. Extraversion did not significantly predict any diagnosis type, while psychoticism predicted a combined category of mood and anxiety diagnoses. Despite intelligence being a significant predictor of the majority of the included diagnoses, adjusting for intelligence did not substantially influence any trait-disorder associations. CONCLUSION: The results confirm high neuroticism as a prospective vulnerability factor for mental disorder and indicate high psychoticism to be a potential risk factor for mood and anxiety disorders. These associations are not confounded by intelligence.

Brain acidosis in experimental pneumococcal meningitis.

Purulent meningitis is a serious disease that often has a lethal outcome or gives lasting complications due to brain damage. The processes causing brain dysfunction or damage are still not uncovered nor are the reasons for the characteristic increase of CSF lactate, or the decrease of glucose levels and of pH. We studied rabbits with experimentally induced purulent meningitis (Streptococcus pneumoniae). Ten hours after the inoculation into cisterna magna the rabbits developed symptoms of meningitis, with stiffness of the neck, tachypnea, and fever. The CSF level of lactate and the number of leukocytes were significantly increased and the glucose level was decreased. Brain interstitial pH, as measured by ion selective microelectrodes, was significantly decreased from the normal level of 7.4 to 6.9. The levels of energy metabolites in brain cortex, including glucose, were not different between controls and infected animals, and the lactate level was not elevated more than could have been explained by passive diffusion from the CSF. This shows that the brain tissue is not the source of CSF lactate nor the sink for glucose in CSF. The marked acidification of brain interstitial space and CSF demonstrates that purulent meningitis causes a significant disturbance of brain ion homeostasis that could be, at least in part, responsible for the brain dysfunction. We suggest that activated leukocytes consume CSF glucose and produce lactic acid and secrete protons, which causes the CSF and interstitial acidosis.