Adjunctive methylphenidate extended release in patients with schizophrenia: Protocol of a single-centre fixed dose cross-over open-label trial to improve functional and cognitive outcomes

Background: Cognitive symptoms, among the core symptoms of schizophrenia, are associated with poor functional outcome and burden of illness. To date, there is no effective pharmacological treatment for these symptom clusters. Augmentation with psychostimulants has been proposed as a potential treatment option. Objectives: The present study aims to assess off-label use of adjunctive methylphenidate extended release (ER) in patients with schizophrenia who are stable on antipsychotic medications, and to assess its efficacy on functioning and cognitive outcome. Methods: This is a single centre study at the Royal Ottawa Mental Health Centre. An open-label fixed dose controlled cross-over trial is planned. Eligible participants will be randomized into one of two arms of the study: 1) four weeks of add-on methylphenidate ER 36 mg, or 2) four weeks of treatment as usual. At 4 weeks, participants will switch arms. The duration of the study includes 8 weeks of treatment and a follow-up visit at 12 weeks. Primary outcome measures include tablet-based tests of functioning and cognition (VRFCAT and BAC) and will be administered at baseline and every 4 weeks. We are aiming to recruit a total of 24 participants. Expected outcomes: The proposed project intends to assess a potential treatment option for cognitive deficits of schizophrenia, for which there are no recommendations by current treatment guidelines. The novelty and significance of the current study is that it investigates this intervention and assess applicability of it in a "real world setting" in a tertiary care hospital.