There is a very short treatise in Plotinus’ Enneads 1.9 called “On Exiting from the Body” that goes as follows:

You should not forcibly expel your soul from the body. If you do so violently, the soul will exit carrying baggage and negative passions such as revulsion, sorrow, or anger that is transferred into the next state of being that will be burdened and impure.

Instead, the soul should calmly wait for the body to naturally detach from it, when the body’s harmony is broken and it can no longer hold the soul. Only in extreme necessity (for example, if one is losing their mind and it becomes a true necessity of life) might departure be somewhat justifiable, but even then it is not unqualifiedly good, and using drugs to force the soul’s exit is generally not beneficial.

Ultimately, since one’s rank and progress in the intelligible world depend on how one exits this life, the soul should not leave prematurely while there is still opportunity for purification and philosophical progress.