Dependency

Dependency is a quest in Fallout 4.

Quick walkthrough
1. Talk to Tina De Luca in the reactor room after rescuing Austin and get the quest to help Bobby get off drugs. 2. Talk to Bobby, you can be nice or mean and get the desired result. 3. Talk to Tina again and give her the good news.

Note: It appears that you can talk to Tina OR Rachel about it to complete the quest, though you may not get the option to invite Tina to your settlement if you speak with Rachel.

Bugs

 * Tina's speech check to invite her to Sanctuary may be broken. This can be fixed by telling Rachel that Bobby is coming.
 * Even if you successfully invite Tina to your settlement and then finish the quest by talking to Rachel she will remain in the Vault 81. If you talk to her again she will mention "seeing the Commonwealth" and "finally getting out" but she won't join the player anyway.
 * Successfully completing Tina's speech check to invite her to a settlment can lead to the quest becoming impossible to complete, with the objecting to speak with her not not marking as complete and it being impossible to initiate conversion with Tina again. Reloading saves seems to be of no use, and the only option to complete the quest is to fail the speech check or not attempt it at all.