symptoms. We did not, however, find evidence of a relation between amplitude of novelty or target P3 and severity of depression or anxiety ratings in patients. This suggests that the diagnostic category or subtype of depression is more closely related to P3 reductions than symptom severity. There is evidence that melancholic (Gangadhar et al.,1993; Ancy et al.,1996; Urretavizcaya et al., 2003) and psychotic (Kaustio et al., 2002; Karaaslan et al., 2003) subtypes of depression have the largest reductions of P3 amplitude. It is also important to note that reduction of novelty P3 is not specific to depression, but has also been found in schizophrenia patients (Grillon et al., 1990; Merrin and Floyd, 1994).
