The present invention provides an agent for improving mental disorders due to cerebral dysfunction and an agent for inhibiting vascular hyperpermeability each containing a hepatocyte growth factor. The agent for improving mental disorders according to the present invention is useful in improving mental disorders, particularly decline in learning and memory function, due to cerebral dysfunction occurred in blood circulation disorders in the brain (for example, cerebral infarction, cerebral hemorrhage, lacunar stroke, Biswanger's disease, cerebral thrombosis, subarachnoid hemorrhage, cerebrovascular moyamoya disease, carotid cerebral arterial fibrous muscular plasia, cerebral arterial sclerosis, internal carotid artery occlusion, hypertensive encephalopathy, cerebral edema, etc.) and neurodegenerative disorders (for example, multiple sclerosis, Parkinson's disease, Parkinson'syndrome, Huntington's chorea, cerebrovascular dementia and Alzheimer dementia), epilepsy, head injury, etc. The agent for inhibiting vascular hyperpermeability according to the present invention is efficacious to blood hyperpermeability in the brain due to blood circulation disorders in the brain (for example, cerebral infarction, cerebral hemorrhage, lacunar stroke, Biswanger's disease, cerebral thrombosis, subarachnoid hemorrhage, cerebrovascular moyamoya disease, carotid cerebral arterial fibrous muscular plasia, cerebral arterial sclerosis, internal carotid artery occlusion, hypertensive encephalopathy, cerebral edema, etc.), blood leakage, edema, subcutaneous hemorrhage and bleeding tendency due to vascular hyperpermeability in various tissues (including internal organs).