Inclusion Criteria of the Primary Caregiver  1. Able to listen, speak, write and read Chinese, report of no psychological problems, and agree to give consent and fill out questionnaires of the study. 3. The potential caregiver whose infant born within one month and needs to be admitted to the intensive care unit for the first time due to an acute and severe illness 4. For those whose infant needs to use the ventilator in admission.  Exclusion Criteria:  1.Have a history of mental disorders including depression, cognitive impairment, addiction to smoking or drinking. 2. The primary caregiver who is the care assistant/carer/nanny of the infant who admitted to the NICU. 3. For those potential caregiver whose infant has congenital abnormality identified by the physician.