Stress genes out of kilter
Max Planck researchers succeed in predicting risk of alcoholism
Scientists from the Max Planck Institute of Experimental Medicine in Göttingen have investigated genetic variations of the corticotropin releasing factor (CRF) system, the biological stress axis, in schizophrenia patients. This system, which consists of various signalling molecules and the receptor structures that interact with them on the cell surface, plays a crucial role in the individual stress response. Hannelore Ehrenreich and her team have demonstrated for the first time an interaction between genetic variants within the CRF system, which show a high predictive value for the risk of comorbid alcoholism.
Alcoholism is a serious and incurable disease that affects up to 20% of the adult population in industrialised countries. The term alcoholism refers to both the serious abuse of alcohol and dependence on it. “The treatment of alcoholism is hampered by an extremely high relapse rate following physical detoxification and even many months of abstinence,” explains Hannelore Ehrenreich, Head of the Division of Clinical Neuroscience at the Max Planck Institute of Experimental Medicine.
Rates of alcoholism well in excess of 30% arise in people who suffer from chronic diseases, for example serious skin diseases, rheumatism, schizophrenia and depression. “It is not difficult to imagine how, in addition to an already debilitating underlying illness, alcoholism has disastrous effects on the disease progression and the patient’s individual situation,” says the physician.
Serious disease is an enormous strain on the patient that may be equated with a severe chronic stress situation. The development of comorbid alcoholism under these circumstances can be evaluated, therefore, as an ill-fated attempt to cope with the stress. As an easily accessible substance, alcohol is used by patients as form of self-treatment which helps them to deal with the effects of internal and external stress and negative emotions.
The genetic configuration of the biological stress axis, in particular the CRF (corticotropin releasing factor) system, constitutes a crucial factor in the individual response to stress. The essential components of this system include the corticotropin releasing factor (CRF) itself, a hormone formed predominantly in the hypothalamus, its receptors (CRFR), meaning the specific binding sites on the surface of the cell that transmit the effects of CRF, and a CRF-binding protein (CRFBP), the function of which is to capture any excess CRF that may be produced.