Drug Withdrawal has many variables. Everything from the type of drug, quantity of regular use, to the length of time the drug was abused, factors into how intense or mild an individuals drug withdrawal experience will be. As mentioned, the type of drug used plays an important part in determining the length and severity of Drug Withdrawal. An example would be withdrawal from methadone; an individual who uses methadone over a period of several months to years and decides to discontinue use will experience a longer and more painful Withdrawal than an individual who discontinues using heroin.

Another factor to be aware of during Drug Withdrawal is drug craving. Drug craving is the result of the drug's imprinting in the memory, a pleasant association of euphoria with the drug. The subconscious memory then motivates the individual to seek this drug because of the false imprint. The brain, in effect, has been trained that using the drug is the fastest way to feel good. Due to the extreme physiological or physical pain some experience during Drug Withdrawal they can relapse before they complete the withdrawal process. This is an important reason that Drug Withdrawal should take place at an inpatient drug rehabilitation center. There the individual will be removed from the immediate access to drugs or alcohol .Drug Withdrawal done at an inpatient drug rehab also provides the safety of medical supervision by trained professionals who are better able to monitor the Drug Withdrawal process.