Final answer:
Major Neurocognitive Disorder and Mild Neurocognitive Disorder can both be caused by multiple etiologies.
Step-by-step explanation:
Major or Mild Neurocognitive Disorder Due to Multiple Etiologies can be attributed to various underlying causes and can manifest as either a major or a mild neurocognitive disorder, or in some cases, stem from multiple contributory factors. When considering learning disabilities, for example, they are commonly identified as neurological disorders, though it's important to note that this doesn't encompass the entire spectrum of neurocognitive disorders, which can also manifest due to other reasons, such as degeneration in specific regions of the brain.
It is often challenging to pinpoint the exact cause of many nervous system disorders because the associated genes might not be known, there may be no obvious defects in brain structure, and the onset and presentation of symptoms can greatly vary among patients. Furthermore, if a child is observed to have impaired social skills, they might be evaluated for disorders such as autism spectrum disorder (ASD), among others.