To the Editor Despite clozapine being the pharmacological agent of choice in treatment-resistant schizophrenia (Galletly et al., 2016), approximately 60% of patients trialled on this medication will have suboptimal clinical response (Siskind et al., 2018). The systematic review by Siskind et al. (2018) addresses the important question of clozapine augmentation strategies and was thorough in its consideration of both pharmacological and non-pharmacological interventions. The consideration of augmentation strategies was broad including electroconvulsive therapy and cognitive behaviour therapy, in addition to nutraceuticals and more novel pharmacological agents such as Ginkgo Biloba, memantine and minocycline. Their review comprehensively summarises the current evidence base and is of relevance to clinicians where augmentation is commonly trialled in the absence of clear guidance.