Katana ZERO

On the Club Neon level, you are ordered not to talk to DJ Electrohead. Do the exact opposite and squeeze him for info about the drugs (at any time during the dialogue, do NOT select the option to "kill him"). You will know you're good when Electrohead gets shot. Proceed with the rest of the level as usual. At the next psychiatrist visit, be resistant about the medication and keep refusing to take it. After you're prompted to leave, the achievement will unlock.

Once you have made it through Club Neon you will receive a phone call not to talk to the DJ Electrohead. You just have to pick any option but kill him, while speaking to Electrohead. After a little bit of a converstaion Elctrohead will be shot and killed. You will go home and rest. Then talk to the Doctor. Choose every option to not take the medication. When you leave the office without taking the medication you will unlock the Refused Medication achievement. Hope this helped!