56 here
I know what it means..
NEET - Neither Education, Employment or Training...
Hikkomori - People who have chosen to withdraw from social life, often seeking extreme degrees of isolation and confinement due to various personal and social factors in their lives.
Now knowing that they ARE similar to a degree a person who is a hikky is NEET and you could also say arguably that someone that is NEET is a hikky/half hikky depending on that person's situation.