According to the Church Committee report (Book I, Chapter XVII):
A special procedure, designated MKDELTA, was established to govern the use of MKULTRA materials abroad. Such materials were used on a number of occasions. Because MKULTRA records were destroyed, it is impossible to reconstruct the operational use of MKULTRA materials by the CIA overseas; it has been determined that the use of these materials abroad began in 1953, and possibly as early as 1950.
Drugs were used primarily as an aid to interrogations, but MKULTRA/MKDELTA materials were also used for harassment, discrediting, or disabling purposes.