All online health information state that diphenhydramine is addictive. is this true ? one person says yes its addictive and the other person says no its not addictive?

There is a difference between addiction an habituation and neither. With addiction you go through physical withdrawal without it. With habituation you develop a habit that is hard to break & tend to use it out of habit. In neither you use it occasionally or even for a while & stop without thinking about it. Diphenhydramine is more of the habit or not, not an addiction.

It has to do with the individual rather than the substance. Addiction is a disease by itself, I have seen patients affected requesting diphenhydramine which otherwise is not likely to become addictive for individuals not affected by addiction.