<h4>Study design</h4>Systematic review.<h4>Objective</h4>The objective of this study was to evaluate the impact of phosphodiesterase (PDE) inhibitors on neurobehavioral outcomes in preclinical models of traumatic and non-traumatic spinal cord injury (SCI).<h4>Methods</h4>A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and was registered with PROSPERO (CRD42019150639). The gene discussed is ALDH7A1; the disease is spinal cord injury.