What is the primary reason individuals experience withdrawal symptoms?

Withdrawal symptoms primarily occur due to the cessation of heavy, prolonged substance use because the body has adapted to the presence of the substance. When an individual regularly uses a drug, their body may develop physical and psychological dependence, leading to changes in brain chemistry and function. These adaptations can include alterations in neurotransmitter systems and tolerance to the drug's effects.

When the substance is suddenly removed or significantly reduced, the body struggles to readjust to its absence, resulting in unpleasant physical and mental symptoms. These can include anxiety, nausea, tremors, and other distressing experiences, making it clear that the body has become reliant on the substance. This process highlights the physiological basis of addiction and the profound impact that certain substances can have on the brain and body over time.