Mindbending

Mindbending is a form of magic which involves influencing the thoughts of others. Its use is heavily regulated by the Ministry of Paranormal Affairs and other such organisations; however it is very difficult to do so. Those that study and master mindbending are potentially very dangerous. However, the art of mindbending is not purely a means of control.
Mindbending, first of all, is only possible if the wielder has a disposition to it. This is very rare in itself and many people who fit that category aren't aware of it (usually because they aren't aware such a thing exists). For the few who are, to actually use it effectively, practise and study are both required. Without those, there is very little one can do with the ability, and nothing a good psychologist could not do with words alone.
In its most extreme form, a master mindbender can:

tune into the surface thoughts of another person

infiltrate the subconscious of another person, implanting thoughts

convince someone they feel the opposite emotion to what they are experiencing

flood them with an entirely new and overpowering emotion

inhibit someone's ability to think clearly by introducing mental blocks

stir up repressed memories and traumas (The mindbender doesn't have to know what they are)

convince someone something different happened to what they remember, and their memory will adjust accordingly

All this can be done with little more than brief eye contact and/or a few words.
The Ministry of Paranormal Affairs trains all its agents in counter-mindbending, the only potential defence against rogue mindbenders. However it offers limited protection against the most skilled mindbenders, such as the infamous Inferno. In general, the study and practise of mindbending is highly frowned upon by the Ministry, but those who could master it have to apply for a license and are heavily scrutinised. At present, there are no licenced mindbenders in the United Kingdom. All research and education materials relating to mindbending are locked in the Ministry's vaults.
Mindbending has a range of non-invasive benefits, outside of espionage or power trips:

a disciplined mind and better mental health for the user

(If the mindbender doesn't choose to block it) magical empathy, which aids connection with other people. (Note that this depends on how open the person is and whether they want their emotions to be known by anyone. For someone intentionally trying to conceal their emotions, the mindbender would not feel anything without forcing the connection, which of course is invasive.)

assist others in processing difficult and traumatic memories

ascertain others' unspoken needs

control dreams and avoid nightmares

make a stubborn person pause and rethink

Given the amount of effort involved, however, as well as the temptations of the more invasive parts of mindbending, the vast majority of people who wish to study it do so for the wrong reasons.