The current study investigates whether an executive processing measure, response inhibition, is stable over time and across new samples of patients with schizophrenia. Two groups of patients (with and without diagnoses of schizophrenia) were followed up 6 years after baseline data collection. Another separate group of patients with less institutionalized care also completed the same measures to determine whether the response inhibition difficulties had the same prevalence in this new sample.The response inhibition measure was stable over time only in the group of patients with a diagnosis of schizophrenia. The relationship between symptoms and response inhibition difficulties changed over time but was explicable in terms of the interaction between environmental demands and information processing difficulties. The level of response inhibition difficulties (about one-third) was identical in the new sample of patients, which suggests that response inhibition is not dependent on clinical history.