Schizophrenia, Psychoticism, Neuroleptics, and Auditory Evoked Potentials

Abstract

Auditory cortical evoked potentials of 20 schizophrenic patients with an acute exacerbation of the illness were investigated before neuroleptic medication and after remission of the acute symptoms, and compared with healthy controls matched for sex and age. Additionally, tests were conducted in 40 healthy volunteers to ascertain whether psychoticism or other personality factors were correlated with evoked potentials. The aim of the study was to test the overarousal hypothesis of schizophrenia and to control the effects of clinical state, neuroleptic medication and personality factors. Acutely ill schizophrenic patients had a shorter evoked potential N1 latency (Table 1). After remission of the symptoms under haloperidol N1 latency of the patients was no longer different from that of the controls. Patients after remission and on medication, however, had longer P2 and N2 latencies and a greater P2-N2 amplitude (Table 2). Psychoticism and extraversion were correlated negatively with amplitude data of components N1 and P2 in healthy volunteers. The results favor the overarousal hypothesis of schizophrenia. Haloperidol normalizes N1 latency in acutely ill patients. It's effect on later components of the evoked potentials seems comparable to a reduction in vigilance. Auditory evoked potentials might allow to follow up the effect of neuroleptics in acute schizophrenia. It seems necessary to consider personality factors when comparing patients with healthy controls in evoked potential studies.

Influence of stimulation parameters on auditory stimulus processing in schizophrenia and major depression: an auditory evoked potential study

“…Thus, the observed latency and amplitude changes may be understood as a result of the differential activation of these subcomponents. An increased P2 latency in schizophrenic patients under neuroleptic medication as we observed it has been described by various authors (41,(45)(46)(47). At the present stage it remains unclear whether the P2 latency increase produced by neuroleptic drugs is related to their antipsychotic efficacy.…”

“…An increased N I latency at higher stimulation frequencies has so far not been reported in schizophrenic patients. At lower stimulation rates, even a reduction of N1 latency has been found (39)(40)(41). It seems reasonable to relate N1 latency to the pro-cessing speed for auditory stimuli (42).…”

Emotional Significance of the Stimulus and Features of the Personality as Factors Reflected in the Pattern of Evoked EEG Potentials

“…Information on these relations is, however, rather contradictory. It was found that the amplitudes of components N1 and Р2 of auditory EPs in healthy subjects negatively correlated with the level of psychoticism [187] and a number of the indices of aggressiveness [188]. At the same time, among teenagers with psychotic deviations, individuals inclined to impulse aggressive behavior demonstrated a higher amplitude of the Р1 component when light flashes and reversion of images were used as the stimuli [189].…”

Psychopharmaka und kortikale evozierte Potentiale

“…In einigen Studien wurden Amplitudenzunahmen der VEP (D'Elia et al 1977, Heninger & Speck 1966, AEP (Schlör et al 1985) und SEP (Josiassen et al 1984) unter neuroleptischer Behandlung von schizophrenen Patienten gefunden, die als Normalisierung der EP gedeutet werden können. Roth & Cannon (1972) beschrieben dagegen bei 21 schizophrenen Patienten eine signifikante negative Korrelation der Pz-Amplitude der AEP mit der Chlorpromazin-Äquivalenzdosis, während die Verhaltensskalen nicht mit den AEPs korrelierten.…”

“…Weitgehend übereinstimmend wurde von mehreren Autoren eine Latenzzunahme der P z -oder N z -Komponente unter Medikation beschrieben (Rösler et al 1985, Schlör et al 1985, Straumanis et al 1982, Sakalis et al 1972.…”