This article reports the results of two related studies investigating the association between affective reactivity of cognitive functioning in schizophrenia and family psychiatric history. In Study #1, we examined affective reactivity of positive formal thought disorder symptoms in 29 schizophrenic inpatients. We found that thought disorder was greatly exacerbated by negative affect in those patients with a family history of schizophrenia (SFH) (n = 11), and not in those without the family history (SNFH) (n = 18). In Study #2, we replicated this finding with a stable outpatient sample (n = 10). We also administered dichotic listening tests using affectively neutral and affectively negative stimuli, and found that right-ear advantage was more markedly diminished on the affectively negative task than on the neutral task in the SFH (n = 6) but not the SNFH (n = 4) subjects. These findings support our hypothesis that cognitive symptoms in schizophrenia are exacerbated by negative affect, and that this affective reactivity of symptoms is associated with a familial form of the disorder.