Scientists examine the causes and treatment of addictive behaviour

November 1, 2013

(Medical Xpress)—Addiction comes in many forms: drugs, alcohol, cigarettes, and gambling have been the types that traditionally plagued society.

In recent years, the proliferation of technology has led to the rise of addiction to the internet and computer gaming. Even the promotion of a healthy lifestyle has led some to become hooked on exercise.

But do all addictions operate by the same biological mechanism? And is addiction an individual's choice or a disease of the brain?

Scientists have been studying addiction for years in order to improve treatments for harmful behaviour. They have found that powerful memories, often of highly pleasurable or intense experiences, underlie addiction. During such experiences the brain releases a chemical called dopamine that creates a reward circuit in the brain, by logging the intense experience as pleasurable and an important action to be repeated.

Dopamine release generally occurs in a region called the (VTA). In response to this, epigenetic changes happen in to form reward memories. These chemical changes are a mix of DNA methylation and demethylation, which either turns genes off or on.

Such a system allows changes in how genes are expressed in cells without altering our genetic code, and forms a type of genetic memory.

Addiction to all four major classes of abused substances - psychostimulants, opiates, alcohol and nicotine - has been linked to the same parts of the brain associated with normal reward processing.

Because of this, scientists originally thought that drug took over normal reward memory nerve pathways. However, a more nuanced picture is now emerging.

In normal reward processing, the VTA signals to another region of the called the nucleus accumbens (NAC).

Explore further: Study explains how the brain remembers pleasure and its implications for addiction

More information:

Related Stories

Morphine and cocaine affect reward sensation differently

October 5, 2012

(Medical Xpress)—A new study by scientists in the US has found that the opiate morphine and the stimulant cocaine act on the reward centers in the brain in different ways, contradicting previous theories that these types ...

New insight into how brain 'learns' cocaine addiction

August 1, 2013

A team of researchers says it has solved the longstanding puzzle of why a key protein linked to learning is also needed to become addicted to cocaine. Results of the study, published in the Aug. 1 issue of the journal Cell, ...

Recommended for you

Placebo sweet spot for pain relief found in brain

October 27, 2016

Scientists have identified for the first time the region in the brain responsible for the "placebo effect" in pain relief, when a fake treatment actually results in substantial reduction of pain, according to new research ...

Team announces mapping of the mouse cortex in 3-D

October 27, 2016

The Allen Institute for Brain Science has completed the three-dimensional mapping of the mouse cortex as part of the Allen Mouse Common Coordinate Framework (CCF): a standardized spatial coordinate system for comparing many ...

Neuro chip records brain cell activity

October 26, 2016

Brain functions are controlled by millions of brain cells. However, in order to understand how the brain controls functions, such as simple reflexes or learning and memory, we must be able to record the activity of large ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.