A symptom is something the patient senses and depicts, while a sign is something other individuals, for example, the specialist take notice of. Example is the case of dilated pupils being a sign while constant sleepiness is a symptom.
Drug Addiction - an addicted person cannot resist or restrict himself to the intake of the substance be it drug, alcohol, cigarette. Even if the substance poses a danger, they will still take it whether or not they know the dangers.
Drug addiction can lead to strong cravings. It will be extremely difficult for the addict to stop using the substance without external assistance, even when they want to.
The symptoms and signs of drug addiction differ according to the person, the drug they are dependent to, their genetics (family history) and personal situations.
Signs and symptoms of substance enslavement may include:
Certain alcohol or substance abusers who aren't technically addicted might also be affected by or cause a few of the above-mentioned descriptions, though these abusers don't generally experience the withdrawal symptoms of addicts or the exact same obsession to use the substance.