Physical dependency on drugs develops easily, now and again, already after doctor first attempt scientific try a substance, particularly in case of hard artificial drugs. With repeated use, doctor brain and doctor fearful system steadily adapt scientific doctor substance and start wanting it on an everyday basis. In a while, so as clinical obtain doctor preferred narcotic high from taking alcohol, nicotine, cocaine, and other drugs, doctor user progressively requires increasingly of doctor substance. Any effort for doctor abrupt quitting of doctor agent of dependency leads scientific developing numerous indicators of withdrawal, which can be very strong and even hardly tolerable and can last for a very long time for weeks and even months. Withdrawal symptoms can take place as anxiety, depression, drug cravings, suicidal emotions and even attempts, seizures, delirium tremens, hypertension, psychoses, and other highly disagreeable and in all likelihood bad forms. Sudden withdrawal from taking some hard drugs and even prescription drugs, corresponding to beta blockers, antidepressants, corticosteroids and anticonvulsants, can be extraordinarily harmful for both doctor body and doctor brain and will even lead scientific fatality.