Arthur Cave fell from cliffs in Brighton on the south coast of England in July and died shortly afterwards in hospital.
A friend who was with him shortly before his death, who cannot be named for legal reasons, said he and the musician's son had shared three LSD tablets and were initially "in good spirits and happy".
However, they split up after the friend started having "vivid hallucinations," according to the summary of his statement read by police to the inquest in Brighton.
Cave, 58, was present for the hearing along with his wife, model Susie Bick.
An inquest is a formal hearing held in England to determine the circumstances of sudden deaths.