Desire Catcher

both:
- revolve around hypnotism-related crimes
- revolve around a task force team designed to handle these odd cases
- feature a police captain and a psychology/hypnotist specialist as the main leads
- feature hypnotism as the main theme and asks the question of whether it is good or bad
- feature a mysterious villain who has plotted everything since the beginning
- leads are not friendly with each other at first but begin to grow closer

SCI is more light-hearted, has more comedy and focuses on the strong bromance between the leads. It doesn't have too much police procedural in it, making it a bit more fast-paced while handling more cases.

Desire Catcher is a lot more serious in tone and has a lot more realistic police procedural in it, making the pace a tad slower but still enjoyable. It takes itself seriously and is a bit more graphic in the cases they deal with. The leads slowly come to like each other and work together.

an investigation involving a mysterious character that manipulates the police into doing his bidding. also to do with hypnotistism

Both are investigative drama with two male leads.
Bromance between them is nice to watch.
Different cases building up to a big case.
Teamwork.

Both are detective dramas
both have male lead detective and kind of suspicious partner helping him solving cases
both have bromance

Both detective dramas
both have partnership between a detective and suspicious partner
both have male friendship

Both are detective dramas
both have psychological aspect in solving cases
both have bromance between male leads

2 ML - one cop with calm persona and one non-cop witty and fun person , cooperate together to crack the case.

Both are detective dramas
both have bromance between two leads
both have psychological aspect in solving cases

Both are detective dramas
both have older younger friendship at odds between the leads
both have bromance

A cop team up with civilian who expert in psychology. Both of drama containing interesting cases with their own characteristics. Justice in the Dark has better chemistry on screen.

Both dramas have a similar feel and are about a detective partnered with a person with a special skill to catch a serial killer who has the same skill and controls their victims' minds in some way. One is fantasy, the other scientific, though.

Dark crime, gripping script, excellent acting, Zheng Ye Cheng main in both dramas. What else needed?

Both are Bromance dramas.
Both are about court, mystery, and action.
I'm adding them here in case you want to watch them.

Both dramas feature serial killings by a victim of an old unsolved case, with a bigger mastermind later revealed behind the scenes. Both have special task force teams created to solve the case, with the main leaders all involved in the said old case. Both also have a psychologist supporting char pretty involved in the investigation. Though in Desire Catcher, there is bromance, there's none (bromance/romance) in The Abyss.
Would def say Desire Catcher was great though!

Both are detective dramas
Both have friendship between two male leads
Both have one of the male leads with a traumatic past
Both have grave crimes