Lysergic acid diethylamide (LSD) remains one of the most poorly understood and mysterious illegal drugs in the world, particularly because its effects are so intense and unpredictable.

On one hand, some people report feelings of intense fear and paranoia while under its influence. They describe a descent into a hell on earth in which they became so afraid that they cowered in closets or checked themselves into a hospital for help. Others report feelings of happiness verging on euphoria. They claim to have attained keen insights into themselves and life.

Mysterious Effects

Often people taking LSD, or acid, face both the highs and the lows. One young user described his experience, often referred to as a trip, in this way: "As my acid trip went on, late at night, the good feelings started to shift to negative feelings...