My dependents medical was received on Feb. ( 1st week ), then got approval after 6 weeks.
my friends dependents medical was received on Dec. 2017, she got approval after 3 months.
I saw somewhere on CIC website that they try to process/or get results within 3 months after they receive medical. But I guess every case is different. just set to expect a results on May 2018. if it comes early, you might cry just like me! hehehe!
good luck! it'll come don't worry

I've been there and trust me, once you get the positive results, its the greatest feeling ever!