Cognitive impairments in patients with psychotic disorder have been associated with poor functioning and increased symptom severity. Furthermore, childhood trauma (CT) exposure has been associated with worse cognitive functioning as well as co-occurrence of affective-anxious-psychosis symptoms or a ‘mixed phenotype of psychopathology’ (MP), which in turn is associated with greater symptom severity, and poor functioning. This study aims to evaluate if cognition could be associated with CT/MP. 532 patients with non-affective psychotic patients were assessed on CT, symptom profile, cognition, functioning, and symptom severity at baseline and 3 and 6-year follow-up. Four subgroups were made according to trauma exposure (CT − or CT +) and presence of a mixed phenotype (MP − or MP +): CT −/MP (n = 272), CT −/MP + (n = 157), CT +/MP − (n = 49), and CT +/MP + (n = 54). Mixed-effects multilevel regression, linear regression, and Tobit analyses were performed. Patients with both CT and MP showed lower verbal learning and memory than CT −/MP + individuals (p < 0.001). No other significant differences were found among the 4 subgroups. No cognitive decline was found at follow-up, neither in the CT +/MP − nor in CT −/MP − group. Lower cognition was not associated with increased symptom severity or poor functioning at follow-up, neither in the CT +/MP − nor in CT −/MP − group. Although cognitive impairments and CT may be related to clinical or functional features of psychotic disorder, and cognitive functioning could be affected by CT exposure, cognition does not discriminate subgroups of patients stratified by CT exposure and MP.