[Quantitative EEG, basic disorders and smoking in etiopathogenetically different groups of paranoid-hallucinatory psychoses--an exploratory study].

We performed an exploratory study of quantitative EEG in aetiopathogenetically different paranoid-hallucinatory psychoses divided into the following groups: a) patients with familial psychoses (n = 12), b) patients with neuropsychological deficits (n = 16), c) patients with alcohol and drug abuse (n = 22) and d) patients with so-called sporadic psychoses (n = 12). We found a significant reduction of relative alpha power in the group with neuropsychological deficits. In the group with familial psychosis there was a significant reduction of absolute delta power and a significant increase of relative beta power and dominant beta frequency, especially for the frontal leads. Patients with drug abuse showed a reduction of absolute beta power and an increase of absolute and relative theta power. The group with sporadic psychosis showed a significant slowing of the dominant beta frequency and a significant increase of the absolute power of fast alpha rhythms. The group with sporadic psychoses showed lowered scores for the paranoid-hallucinatory basic symptom factor. The group with neuropsychological deficits showed the most visceral-somatoform basic symptoms, the highest nicotine consumption, increased dyskinesias and more perinatal complications. This group also showed the highest level of neuroleptic and antiparkinson medication. All in all, the group with neuropsychological deficits showed a complex interaction of somatic-exogenic and medical-iatrogenic factors. Furthermore, there was a significant positive correlation between paranoid-hallucinatory basic symptoms and nicotine abuse and high frequency beta waves.