It is a good idea to to take feral scream early if your laning against a melee champ who relies on there abilities quite a bit. Weigh weather its worth it or not because the silence duration isn't very long when the ability is maxed out much less at first rank. You can often accomplish the same task of stopping them from using there ability with a properly timed rupture while doing damage and then slowing them after they land.

Feral Scream along with a properly timed rupture can however shut down certain melee dps/ close range magic dps such as Master Yi, Katerina, and Tryndamire. Hitting them with a rupture then following it up with a Feral Scream will stop them from attacking for a bit then stop them from casting their ult which can quickly turn a fight against them. Especially if used near the end of a fight or timed well in the beginning if you have the allies available to kill them quick enough. Just keep in mind how small of a range Feral Scream has, it can be useful but you need to know how to use it depending on the situation.

If you're facing a tankmage like Nunu or a combination that makes it hard to kill the magic user, it might pay off to take one level of Feral Scream early on just to be able to silence them for a second. It's especially handy when the magic user you're facing is a close combat fighter as well.