Scientists examine the causes and treatment of addictive behaviour

(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).

More information: www.scmp.com/lifestyle/health/… -addictive-behaviour

add to favorites email to friend print save as pdf

Related Stories

Morphine and cocaine affect reward sensation differently

Oct 05, 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 ...

Recommended for you

Researchers unlock mystery of skin's sensory abilities

Dec 19, 2014

Humans' ability to detect the direction of movement of stimuli in their sensory world is critical to survival. Much of this stimuli detection comes from sight and sound, but little is known about how the ...

Tackling neurotransmission precision

Dec 18, 2014

Behind all motor, sensory and memory functions, calcium ions are in the brain, making those functions possible. Yet neuroscientists do not entirely understand how fast calcium ions reach their targets inside ...

User comments

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.