Jm. Olichney et al., RELATIONSHIP BETWEEN AUDITORY P300 AMPLITUDE AND AGE-OF-ONSET OF SCHIZOPHRENIA IN OLDER PATIENTS, Psychiatry research, 79(3), 1998, pp. 241-254
Auditory P300 amplitude reductions are well-established in young adult
s with schizophrenia. Little is known, however, regarding the P300 in
older schizophrenia patients, especially those with late onset. We stu
died 28 middle-aged and elderly (mean age = 62.7 years) patients [14 w
ith early onset schizophrenia (EOS) and 14 with late onset schizophren
ia (LOS)] and 14 normal comparison (NC) participants using an auditory
oddball paradigm. Event-related potentials were recorded from 15 scal
p electrodes and six non-scalp sites. There were no significant differ
ences between EOS and LOS groups in neuroleptic dosage, symptom severi
ty, reaction times, target-detection accuracy, or N100 and N200 ERP me
asures. The EOS, but not the LOS, group had significantly smaller audi
tory oddball P300 amplitudes than the NC group. Twelve of the 14 LOS p
atients had P300 amplitudes in the normal range. Smaller P300 amplitud
es were associated with earlier age of onset (r = 0.48), longer durati
on of illness (r = -0.49) and more severe alogia (r = - 0.50). We conc
lude that P300 abnormalities in schizophrenia may be a marker for a di
sease subtype with early onset and more severe information-processing
deficits. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.