Actually I believe what the Bhikkhu said is possible.. although
I cannot verify it myself because I do not have powers to read
people's past life. But I heard of a similar story.
I would like to share a with you a true story which was told by
a Venerable. There was a Venerable who had the powers to know a
person's previous existence. There was a couple who had a child
with low mental capabilities and they asked the venerable why was
that so. The Venerable answered - that child of yours was a drug
lord in the previous life and has caused much mental delusions and
intoxications to others, and therefore that was his karma. The
parents then asked abruptly, if that was the case then why were
they affected too? (to have the responsibility to take care of that
child). The Venerable continued, "let me finish explaining. You two
were his accomplice in selling the drugs while he was the
mastermind and therefore it was your karmic consequence for having
him as your child." Therefore I think whatever child was borned,
that was his karma, by karmic association. He should accept it,
give extra love and patience to bringing up their child.
Because one loves that intoxicated state, in that intoxicated
state the mental ability and clarity is reduced to the level of
retard/idiot, and so he plants many karmic seeds of mentally
intoxicated/'retarded' karma into his 8th consciousness, which may
ripen in another lifetime.
Well it's up to you to believe, I dont mean that I know this will
definitely happen to those drug abusers because I do not have such
powers to see people's past life, but I'm saying it is a
possibility. And if the drug abuser commits greater crimes while
under the influence of drugs or alcohol, that's even worse, he
might fall into the lower realms. So karma should not be taken
lightly.