Short answer: there is no reliable clinical evidence that combining psilocybin and ketamine is safe or effective for PTSD. I cannot verify claims of benefit, and safety data on the combo are lacking.
Mixing these substances can be unpredictable. Potential risks include intense disorientation or dissociation, anxiety or panic, nausea, impaired coordination and judgment, and changes in blood pressure or heart rate. Interactions with medications or mental health conditions may raise risks further.
If someone is considering this, avoid unsupervised use. Seek qualified, legal clinical oversight, do not add alcohol or other drugs, and plan for proper screening, continuous monitoring, and post-session support.
This mix is sometimes called a “funky flip” or “chonk,” as discussed in this article: ketamine with psilocybin. I hope this helps; stay safe.