Some alcohol use is normal, but excessive use can be a serious security concern. Alcohol affects the central nervous system and how the brain functions. Excessive use affects perception, thinking and coordination. It impairs judgment, reduces inhibitions, and increases any tendency toward aggression. Those who abuse alcohol are more likely than others to engage in high-risk, thoughtless or violent behaviors. This increases the risk of unauthorized disclosure of classified information due to impulsive or careless behavior. Excessive alcohol consumption often leads to questionable judgment or the failure to control impulses and can raise questions about an applicant’s reliability and trustworthiness. Evidence from past espionage cases indicates that alcohol problems are more prevalent among convicted spies than in the population as a whole.