Heroin and syringe
Addictive cravings are still persistent after death, finds a new study.

A protein in the reward center of the brain is altered in those suffering from a chemical dependency - it is split off and shortened.

Following numerous autopsies, Austrian researchers found the modified protein in deceased heroin addicts - suggesting cravings for the stimulus continued after their death.

The protein, called FosB, is a transcription factor in the brain which, together with other molecules, is involved in so-called signal transduction (transmission of stimuli to the cells). It is said to convey genetic information between the cells and also determines whether certain genes are activated or not. FosB is part of the activating protein AP1, which is involved with regulating gene expression in response to a range of stimulus, including stress and bacterial infections.

Due to a constant supply of drugs, such as heroin, FosB turns into DeltaFosB, which is increasingly stimulated in cases of chronic use and even influences growth factors and structural changes (neuronal plasticity) in the brain - approximately in the region where memory is formed

The evidence that the modified protein lingers after death was discovered by the Medical University of Vienna's Department of Forensic Medicine, which examined tissue samples from the nucleus accumbens (an area of the brain) of 15 deceased heroin addicts. 'Using highly sensitive detection methods, DeltaFosB was still detectable nine days after death,' the team explained.

Although the mutation of the protein can be identified more than a week after death, researchers believe the period is much longer in the living who are trying to recover - and it can last for months.

They also suggest these results will help advance treatments and management of people with opiate dependencies and heroin addictions, with how to deal with withdrawal being the focus. 'If the addictive craving persists in the brain for months, it is very important to provide protracted after-care and corresponding psychological support,' said Monika Seltenhammer, a researcher involved in the study.

'Our results show that forensics and forensic medicine can also be of direct benefit to the living,' emphasized Daniele Risser, the lead author.

In a follow-on project to be conducted in collaboration with MedUni Vienna's Institute of Pharmacology and Center for Addiction Research and Science (AddRess) and the objective is now to further understand the if and how the activation of DeltaFosB can be prevented and how this highly promising starting point can be used to treat the onset of addictive behavior.