"Addiction" is defined as a behavior that impairs other aspects of your life to a large degree, so yes, even a reading addiction would have these effects by definition.
This has the disadvantage that it is near-totally unrelated to what most people think of as "addiction". But it has the advantage that it is a coherent concept, which isn't true of most offered definitions.
In the vernacular, "addiction" just means that you disapprove of someone's behavior.
In medicine outside psychiatry, "addiction" refers to the phenomenon of physical withdrawal symptoms in the absence of something. For no particularly good reason, you are not considered to be addicted to oxygen. But that's not part of the definition, it's an implied codicil.
Psychiatry defines a single "addictive disorder", which is compulsive gambling. Nothing else is considered addictive. This seems to be a response to the fact that no one has ever provided a workable definition of addiction. (See e.g. https://www.porticonetwork.ca/web/fundamentals-addiction-too... : "The term addiction is no longer used to describe substance use disorders. It was felt that the term was so loaded with associations that it lacked precision.") This comic ( http://www.smbc-comics.com/comic/2014-03-21 ) provides an amusing illustration of the issues. But for a less irreverent joke at psychiatry's expense, this formal paper ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5328289/ ) spends some time making fun of the fact that compulsive gambling is the unique "addictive disorder" while compulsive stealing, which is mostly identical except in the specific behavior expressed, is an "impulse control disorder".
Here's how the different systems classify caffeine:
Vernacular: addictive if you're a Mormon; not otherwise.
Economics: not addictive; no increasing returns.
Medicine: addictive. (Withdrawal causes severe headaches.)
Psychiatry: not a substance use disorder. (Consumption of caffeine may be compulsive, but it is not a "disorder", itself not a well-defined term.)
I suggest to you that the definition you provided, "a behavior that impairs other aspects of your life to a large degree", comes from psychiatry, but is actually part of the definition of a "disorder", not an "addiction".
That aside, I'd like to congratulate you on how non-confrontational your comment was, making it easier for me to reply that you've taught me something. I will try to emulate that in my comments in the future.
Addiction Medicine (ADM) is a recognized physician subspecialty of the American Board of Medical Specialties. [1]
Addiction is a treatable, chronic medical disease involving complex interactions among brain circuits, genetics, the environment, and an individual’s life experiences. People with addiction use substances or engage in behaviors that become compulsive and often continue despite harmful consequences. [2]
Dependence or physical dependence is used in the psychopharmacological context in a narrower sense, referring solely to the development of withdrawal symptoms on cessation of drug use. [3]
[1] https://www.drugabuse.gov/nidamed-medical-health-professiona...
[2] https://www.asam.org/resources/definition-of-addiction
[3] https://www.who.int/substance_abuse/terminology/definition1/...
A good psychiatrist uses the ICD and DSM as a guide and not as a rule. The two key factors that contribute to a gaming disorder, according to ICD-11 are:
1. increasing priority given to gaming to the extent that gaming takes precedence over other life interests and daily activities; and
2. continuation or escalation of gaming despite the occurrence of negative consequences. The behaviour pattern is of sufficient severity to result in significant impairment in personal, family, social, educational, occupational or other important areas of functioning.
This can be applied to many things reasonably. Each is not going to get its own category as an addictive disorder. A good psychiatrist would, however, still be able to identify that there may be a problem if these two conditions are met for a different activity.