A 3-year-old girl with a history of prenatal exposure to methamphetamines is brought to the PMHNP by her grandmother for an evaluation of her readiness to attend preschool. She demonstrates substantial delays across multiple domains of functioning, including communication, learning, attention, and motor development. These deficits will limit her ability to interact with same-age peers. She also requires substantial support in all activities of daily living at home. Due to custodial circumstances, her grandmother is a poor historian and is unable to provide information about the age of onset for these symptoms. What is the most appropriate diagnosis?