Dependence is not the same as addiction
Substance dependence means the body adapts so that stopping brings withdrawal and drives reuse. Addiction is compulsive use despite harm. DSM-5 dropped separate abuse and dependence labels in 2013, folding them into substance use disorders—because tolerance alone can be a normal drug response.
Dependence is a biopsychological state: after repeated psychoactive use, function hinges on taking the substance again because an adaptive state has formed that produces withdrawal. Addiction, by contrast, is compulsive, out-of-control use despite bad outcomes. Addictive drugs are both rewarding and reinforcing. The transcription factor ΔFosB is described as critical across nearly all behavioral and drug addictions, but not for dependence itself. ICD classifies substance dependence as a mental and behavioural disorder. DSM-5 (2013) removed separate substance abuse and substance dependence diagnoses after concluding that tolerance and withdrawal—once hallmarks of dependence—are often ordinary responses to prescribed CNS medicines and need not signal addiction.
Withdrawal is the unpleasant rebound when a dependent person stops; continued use then escapes that state through negative reinforcement. Symptoms can be physical-somatic, emotional-motivational, or both, with chemical and hormonal imbalances and psychological stress if the drug is not restored. Infants can show neonatal abstinence syndrome, which can be severe. Dependence liability varies by dose, frequency, pharmacokinetics, route, and timing. In the nucleus accumbens, CREB activated after a high alters gene expression including dynorphin, which temporarily dampens dopamine release—pushing larger doses for the same effect and leaving anhedonia that often pulls the user back.
Koob and Kreek link escalating use to rising corticotropin-releasing factor and stress-system activity in the extended amygdala. Treatment goals differ by place: U.S. programmes often aim at total abstinence, while many European approaches count reduced interference with work and family, safer routes of use, less crime, and care for co-occurring illness as success even without full abstinence. Residential paths include twelve-step groups and therapeutic communities; cognitive-behavioural therapy treats addictive behaviour as learnable and, for some, controllable rather than only a disease to extinguish.
Source: Substance dependence
