Heedlessness means moral recklessness, disregard for the bounds between right and wrong. To indulge in intoxicating drinks is to risk falling away from each stage. The use of alcohol blunts the sense of shame and moral dread and thus leads almost inevitably to a breach of the other precepts. One addicted to liquor will have little hesitation to lie or steal, will lose all sense of sexual decency, and may easily be provoked even to murder. Hard statistics clearly confirm the close connection between the use of alcohol and violent crime, not to speak of traffic accidents, occupational hazards, and disharmony within the home.
Alcoholism is indeed a most costly burden on the whole society.
When the use of intoxicants eats away at even the most basic moral scruples, little need be said about its corrosive influence on the two higher stages of the path. A mind besotted by drink will lack the alertness required for meditative training and certainly won't be able to make the fine distinctions between good and bad mental qualities needed to develop wisdom. The Buddhist path in its entirety is a discipline of sobriety, a discipline which demands the courage and honesty to take a long, hard, utterly sober look at the sobering truths about existence. Such courage and honesty will hardly be possible for one who must escape from truth into the glittering but fragile fantasyland opened up by drink and drugs. It may well be that a mature, reasonably well-adjusted person can enjoy a few drinks with friends without turning into a drunkard or a murderous fiend.