The study has been carried out in Helsinki University, at the Department of Public Health and the Department of Psychology. The responsible researcher in Finland has been Prof. Jaakko Kaprio, but the study group also has researchers from Indiana University, USA.
The study consists of twin pairs who have participated in the Finntwin16 and in the follow-up in 2000-2002. Both twin pairs with very similar alcohol use and twin pairs with dissimilar alcohol use have been picked up to the study. Additionally, included are some randomly picked twin pairs functioning as a control group for the study.
Abundant use of alcohol and it's effects in brains has been studied a lot, but studies of minor use of alcohol and it's effect to central nervous system are a lot more uncommon. One of the targets of this study is to understand how even a minor use of alcohol effects in brains. Results of the study can be utilized when new recommendations of alcohol use in relation to public health are given.
In neuropsychological and neurophysiological studies divergence between individuals is great. In twin study, these differences can be minimized by comparing each twin pair so that the effect from genotypes and childhood can be scientifically controlled. This is the reason why the study requires both twin pairs with similar and dissimilar alcohol use. The alcohol use of people in the study represents normal distribution of alcohol use in Finland.
Electroencephalography (EEG) is used to measure brain's voltage response related to attentiveness and function of short-term memory. According to previous studies voltage responses are very sensitive to the effects of large scale consumption of alcohol. This study is seeking to find out how minor use of alcohol effects the voltage responses of brains. This method gives precise information about the effects of alcohol in brains.