Helsinki, May 1 (IANS): A team of Finnish scientists has decoded changes in the brain that make people prone to excessive drinking -- a discovery that can lead to new drug therapies to treat alcoholism.

The brain tissue of people with alcohol dependence shows a variety of hormonal and neurotransmitter changes compared to non-alcoholics.

All alcoholics' brains share some characteristics but some are exclusive to the brain tissue of anxiety-prone Type 1 alcoholics or impulsive Type 2 alcoholics, according to researchers from University of Eastern Finland.

The researchers analysed post-mortem brain tissue from alcoholic people and non-alcoholic controls.

Alcoholics were divided into two groups - Type 1 and Type 2 alcoholics.

Type 1 alcoholics develop alcohol dependence relatively late in life and are prone to anxiety.

Type 2 alcoholics, on the other hand, develop alcohol dependence at a young age and they are characterised by anti-social behaviour and impulsiveness.

"From the viewpoint of the study, this division was made in order to highlight the wide spectrum of people suffering from alcohol dependence," said lead researcher Olli Karkkainen.

One of the changes shared by all alcoholics were increased levels of dehydroepiandrosterone in the brain.

Dehydroepiandrosterone is a steroid hormone that affects the central nervous system.

The increased levels can explain alcohol tolerance which develops as a result of long-term use and in which alcohol no longer causes a similar feeling of pleasure as before.

"Moreover, all alcoholics showed decreased levels of serotonin hormone associated with recognition of feelings and social cognitive processes.

The finding could be related to social anxiety type behaviour seen in alcohol-dependent individuals.

The findings were published in the journal Alcohol and Alcoholism, Psychiatry Research: Neuroimaging, and Alcohol.