In short, yes. I have personally and professionally witnessed this. However, it is not ayahuasca itself that causes a psychotic break, but rather a combination of factors that includes the state of one’s psyche, how the substance is used (or rather abused), what level of integration support is available, and whether or not the person dispensing the substance is appropriately trained.
In western culture, psychoactive plants are called drugs and are illegal. They are classified and given a rating based on their potency. In the UK, Ayahuasca is a class A drug. This means it is considered dangerous and high-risk.
In indigenous and shamanic culture, psychoactive plants are called “medicine” and are used for the purpose of healing and divination. Ayahuasca is revered as a powerful healing tool (“spirit”) when used in combination with a shamanic ritual.
In the west, psychedelic healing is experiencing a resurgence, however, our understanding of such (spiritual) technology remains in its infancy. We are presently ill-equipped to offer psychedelics as a healing modality due to our lack of awareness and understanding of the transpersonal planes of existence; which has always been the domain of the shaman.
Consequently, people experiencing a bad “trip” or struggling to integrate their exposure to transpersonal realms are pathologized, labelled as psychotic or schizophrenic, and treated as psychologically abnormal. Such an approach is ultimately not helpful and is akin to the “blind leading the blind”. Hence why drugs, even when dressed up as “medicine” remain illegal for the time being.
If we are to legally offer psychedelics as an avenue for healing, we must become shamans ourselves and (re)learn how to navigate the transpersonal planes of existence and its effect on our anatomy and physiology. Or at the very least, we need access to an informed community/network that can offer support with the integration of such expansive experiences.
Shamanic training is long and arduous. In much the same way that training to be a surgeon requires a minimum 8–10 years, so it is with shamanism. And just like surgery, shamanism is highly skilled and delicate work that walks a knife edge between life and death. An ill-equipped and untrained shaman can cause irreparable damage in the same way a surgeon can.
The upshot is, if the person dispensing ayahuasca is not an accomplished shaman who can also assess your suitability for such an “operation” and provide adequate aftercare, you are taking massive risks with your mental and physical wellbeing.
Messing around on a high-wire without a safety net is not advisable, anymore than allowing someone who’s watched a few episodes of “House” to perform surgery on you.