My parents are small business owners, so I've always had an interest in running a business. From what I understand though, there are no procedures in psychiatry, so what's the scope for additional revenue streams beyond seeing new patients, med checks, and psychotherapy?
Consulting (business side of things)
Hiring midlevels to extend practice
Owning the building and charging rent to other providers
Clinical trials
Rehab facility
TMS
ECT
Giving talks
Writing articles
Writing books
Blog
Open a med spa (botox/dermal filler/etc)
Open a franchise
Etc.
As you can see -- there is a wide range of possibilities -- some have low barriers to entry, others being high.
Some of the above require a bit of skill (i.e. if you aren't a powerful speaker, no one would pay you to give a talk regardless of your message) or luck (i.e. even if you are a great writer, there is the real chance that none of your books will be wildly successful).
Others seem to not make immediate sense. A med spa? "Could a psychiatrist even do those types of treatments? Would anyone go to such a spa?" Apparently so -- I went to school with a kid that works at his father's dentistry practice. He does botox and dermal filler treatments...and from what I hear, a lot of them. It is all about reputation. If the kid has a rep for good results wielding botox, people don't care that the initials after his name are "DMD". At least you have a head start by having "MD" after your name on the med spa's website.
"Open a franchise"?! I can imagine a *certain predictable poster* on here coming in and replying with "What? Are you crazy? That isn't special to a psychiatrist. A cashier at a department store could open a franchise!" ...Not exactly. Good luck to that cashier at the department store in having the requisite level of assets and ability to attain the line of credit needed to pursue such a venture.
Essentially, you are limited by your creativity, motivation, acumen and [sadly] dumb luck.
From what I hear, as a psychiatrist you have the benefit of being able to often control your schedule and hours. If you only want to dedicate 30 hours to your clinical practice and another 30 hours per week to some other revenue-generating pursuits -- it is doable (and wise to diversify income streams). Good luck to some of the other specialties that work 60 hours per week regularly -- much harder to find those 30 extra hours each week to diversify income.