There are five aspects to addiction – the more addictive the drug, the more pronounced these issues are:
Withdrawal Symptoms: the more addictive a drug, the more severe the withdrawal symptoms
Reinforcement: this is also known as craving. The more addictive the drug, the most likely you are to crave taking it again and again.
Tolerance: if you have to increase the dose of the drug over time to get the same effect, this means you have developed tolerance to the drug.
Dependence: the more addictive the drug, the harder it is to quit and the harder it is to stay off the drug
Intoxication: How high does the drug get you? Alcohol is actually the most intoxicating drug.