Well, could’t You say the same thing about experiences of any nature? For example: our thoughts always affect our body/mind .. if I take a drug or in the case of ayahuasca an entheogen, it creates a non ordinary state of consciousness, which -if strong enough- can permanently change the way I feel and act. The same you could achieve by meditating on a regular basis or going on a long trip, having a traumatic experience etc .. our brains are being modified constantly by our experiences, not just by drugs. And yeah, a belief is a belief - if it’s a conscious belief you could say ‘I believe in having this belief’ and if it’s unconscious it’s just a belief I am not consciously aware of. But both have the same Effect on my body and mind