These post-acute withdrawal symptoms have also been demonstrated in animal models of alcohol dependence and withdrawal.[66] A kindling effect also occurs in alcoholics whereby each subsequent withdrawal syndrome is more severe than the previous withdrawal episode; this is due to neuroadaptations which occur as a result of periods of abstinence followed by re-exposure to alcohol. Individuals who have had multiple withdrawal episodes are more likely to develop seizures and experience more severe anxiety during withdrawal from alcohol than alcohol-dependent individuals without a history of past alcohol withdrawal episodes. The kindling effect leads to persistent functional changes in brain neural circuits as well as to gene expression.[67] Kindling also results in the intensification of psychological symptoms of alcohol withdrawal.[65] There are decision tools and questionnaires which help guide physicians in evaluating alcohol withdrawal.