How are the addictive properties of coffee different than other addictive substances which I assume is frowned upon in Judaism.
I would hazard to guess from a purely logical perspective that the main reason is because whilst increased amounts of caffeine are not great for the person, they do not pose the same physical danger that alcohol, cigarettes and drugs do, and for that reason are not an issue.
(Although, if it is having an adverse effect, I imagine both the medical and rabbinic advice would be to avoid it.)
This is all based on the principal in Devarim 4:15 -
וְנִשְׁמַרְתֶּ֥ם מְאֹ֖ד לְנַפְשֹׁתֵיכֶ֑ם
“You shall guard your soul very well”
This injunction is understood to take care of one’s body and avoid taking any risks that might jeopardise one’s physical wellbeing.
Note the Kitzur Shulchan Aruch 32:1 which encapsulates this requirement:
הואיל והיות הגוף בריא ושלם מדרכי השם הוא שהרי אי אפשר שיבין או ידע דבר מידיעת הבורא והוא חולה לפיכך צריך האדם להרחיק את עצמו מדברים המאבדין את הגוף ולהנהיג את עצמו בדברים המברין והמחלימים את הגוף וכן הוא אומר ונשמרתם מאד לנפשותיכם
Because the maintenance of a complete and healthy body is a G-dly path – since it is impossible to understand or apprehend any knowledge of the Creator when one is sick – therefore you must keep away from things that damage the body, and develop habits that improve the body and heal it. Similarly, it is said: “You shall guard your soul very well.
Interestingly enough, since coffee is a stimulant, it is actually brought down in halacha as potentially a good thing. The Mishnah Berurah 89:22 speaks about having it before davening if by consuming it, will enhance a person's prayers:
וטיי"א וקאפ"ע מותר לשתותו קודם תפלה כדי שיוכל לכוין דעתו ולהתפלל ובפרט בהמקומות שרגילין בהם ואין מתיישב הדעת בלתם...
Tea and coffee are permitted to be drunk before prayer in order that one will be able to concentrate, especially in the places where he is used to and the mind does not settle down without it...
Rav Moshe Feinstein Zt"l writes in Igros Moshe Yoreh Deah 3, 35 about the prohibition of smoking marijuana. “It is obviously forbidden to smoke marijuana, as this violates many basic laws of our Torah. First of all, it physically injures the person. Even if there are people who are not physically affected by this, it mentally affects the person as it destroys his mind, and prevents him from understanding things properly. This is a terrible thing, since not only can the individual not properly study Torah, he also can not pray and properly perform Mitzvos (commandments), since doing them mindlessly is considered as if they were not done at all. Furthermore, he is creating within himself a very strong desire (addiction?), which is much stronger than the desire to eat, etc. which are necessary for a person to live. There are many that can not control and withstand this desire. This is a very grave prohibition, as we find that a Ben Sorer U’Moreh [is killed] (See Deut. 21:18) for creating within himself a very strong desire, even though it is to eat Kosher food! How much more so it is forbidden for a person to bring upon himself an even greater desire, especially for something that a person does not need at all… Additionally, the parents of the person smoking certainly are disturbed by his actions, in which case he is violating the Mitzvah of Kibbud Av V’Em (respect for parents). He is also violating the Mitzvah of “Kedoshim Ti’Hiyu”(be holy), as explained by the Ramban in his commentary on the Chumash (5 Books of Moses). This also leads him to transgress other prohibitions, besides the actual prohibition of taking drugs. The bottom line is that it is clear and obvious that this is one of the grave prohibitions, and everyone must try with all of their strength to remove this impurity (Tuma’ah) from all Children of Israel.”
Accordingly, seeing as caffeine has not got any of these issues therefore it is not frowned upon.
Coffee is beneficial for your liver. I'm sure there's a point of too much but so far the usual correlation of too much coffee and adverse health effects is from also smoking cigarettes. So the main difference is while too much coffee might be bad for you. Just enough is beneficial and that is not the case with addictive illegal drugs which are damaging at any amount