They neglect obligations at work and their commitments at home and family start to wane.
They take risks that are personally dangerous and put others in jeopardy such as driving or operating machinery while intoxicated.
They violate the law by engaging in disorderly conduct or assaultive behavior.
Interpersonal problems: they always have strained relationship with self and others, peers, friends, family.
Continuous use of drugs even when it is clear that such behaviour entails significant risks or create problem in living.
Drug addicts seem to have no direction in life because they are always looking sad, mostly when the effect of drugs has waned.