A PhD is the highest level of educational attainment particular to a specific field of study. What you can do with it, is up to you. You can go out and use it to benefit others, or you can use it for wall paper. The choice is yours.
Doctor (Dr.)
i have a PhD in....
No, unless he/she has a PhD
The title "Dr." is used for individuals who have earned a doctoral degree, such as a PhD, MD, or EdD. However, "PhD" specifically refers to a doctoral degree in philosophy. Use "Dr." as a general title for all individuals with doctoral degrees, including those with a PhD.
Yes, it is not necessary to use both "Dr." and "PhD" together when addressing someone with both titles. "Dr." is typically used as a title for individuals who hold a doctoral degree, such as a PhD.
Yes, if they have already achieved their PhD. If they have not, then no. They are just PhD students or post-graduate students
How does anyone 'use' a PhD except to put it after their name? Bart van Herk (PhD, Rotterdam, Netherlands).
Yes, individuals with a PhD typically use the title "Dr." before their name as a sign of their academic achievement and expertise in their field.
If you mean in a sentence, than, "The Doctor has a PhD in medication."
Yes, it is appropriate to address someone with a PhD as "doctor" as they have earned a doctoral degree which entitles them to use the title.
When addressing someone with a PhD in an email, it is appropriate to use "Dr." followed by their last name. For example, "Dr. Smith."
Run the zombies in a circle around the lander near PhD Flopper, and use PhD when possible to conserve ammo.