Haggard, ravaged and gaunt: the photos of crystal meth addicts show clearly how the drug drastically alters a person's appearance.

Now, scientists have discovered how the drug affects the body's cells to speed up ageing.

They found crystal meth - or methamphetamine - causes abnormalities in the fat metabolism of cells.

This, in turn, triggers a rise in a type of molecule which promotes cell death. 

According to The Daily Mail, methamphetamine is a highly addictive drug, which gives users a feeling of euphoria and increased energy levels.

It damages the brain and other body organs, and post-mortem examinations have linked use of the drug to diseases associated with ageing, such as coronary atherosclerosis – a hardening of the arteries - and pulmonary fibrosis – scarring of the lungs.

Until now, the mechanisms underlying these diseases have remained unknown.

As part of the study, researchers at the University of California, Irvine, allowed rats to self-administer methamphetamine, and studied how the drug affected their cells.

They found the drug caused abnormalities in fat metabolism in the cells.

This triggered extreme inflammation, which was evident through a sharp rise in the formation of ceramides.

These are inflammatory molecules that cause cells to age and die.

The scientists discovered the production of ceramide involves a specific protein called nuclear factor kappa beta.

Normally, this protein helps regulate the DNA of other proteins, so the body functions normally. 

However, methamphetamine causes the cells to let out signals.

This, in turn, induces the nuclear factor kappa beta inside the cell to let out signals, which triggers the dramatic increase in the production of cell-ageing ceramide.

Normally, ceramide regulates how cells use energy and nutrients, so when it's activity is amplified, the cell's metabolism is also sped up.

'We found this signaling process to be key for advanced cellular aging, which is at the heart of the accelerated aging influenced by methamphetamine abuse,' said Professor Daniele Piomelli, of University of California, Irvine, who carried out the research.

After identifying the effect the drug was having on the body's cells, the researchers tested whether inhibiting nuclear kappa beta from sending out signals would halt the production of ceramide.

Theoretically, this should stop cells prematurely ageing.

They found that they were actually able to prevent rats cells from withering and dying, curtailing the deterioration of the rodents' health.

'These results suggest new therapeutic strategies to reduce the adverse consequences of methamphetamine abuse and improve the effectiveness of abstinence treatments,' Professor Piomelli said.

He is currently working with colleagues at the Italian Institute of Technology, in Genoa, to create a form of the inhibitor compounds that could be used by health professionals or the public.