Alexithymia is common in patients suffering from a variety of disorders, such as schizophrenia spectrum disorder. Affectivity has been considered as an individual’s characteristic that seems to modulate the relationship between personality traits and some psychological/medical symptoms. The aim of the present study was to investigate the relationship between negative and positive affect, alexithymic characteristics and psychopathology in a sample of psychotic patients. Thirty consecutive outpatients were assessed using the PANSS, the TAS-20, and the PANAS. Pearson correlations were applied to investigate the relationship between the study variables; the amount of variance in psychopathology predicted by alexithymia and affectivity was calculated by using the linear regression model. Significant relationships between psychopathology and positive and negative affect were found; negative symptoms were strongly associated with the individual’s difficulty on describing feelings and negative affect. Results provided a new approach to interpret affectivity and individual’s alexithymic traits as determinants of psychotic symptomatology.