Dependence, tolerance, and withdrawal are progressive in substance abuse disorders. Repeated overstimulation eventually leads to a numbed response. Over time the VTA no longer fires neurons, decreasing the supply of dopamine and triggering cravings. As tolerance increases, the brain demands more stimulation to produce the same effect. Simultaneously the brain is learning to embed associations (triggers) of the reward/pleasure event. Inhibitions weaken and self-control is overridden. Addiction is established.
The bad news – few addicts recognize when they have crossed the line. The good news – you can rebuild your life.
A diagnosis of addiction, involving nicotine, alcohal and other drugs, is defined as having more than 2 symptoms over a one year period.
Severity of disease: Mild (2-3) Moderate (4-5) Severe (>6)
Source: Diagnosis and Statistical Manual of Mental Disorders (DSM) -5