The relationship between alcohol or illegal drug use and criminal activity is recognized as a serious social problem around the world and has been widely researched worldwide. Even though there is no direct association between them, it can be suggested that consuming large quantities of alcoholic beverages, for instance, is directly related to violent crimes. However, other criminogenic factors must always be taken into consideration. Alcohol, illegal drugs and crime may also be linked through shared complicating factors such as personality issues and social disadvantages. The Brazilian penal system does not punish individuals who, at the time of their crime, did not have the capacity to understand the unlawfulness of their actions or to behave in accordance with this understanding. Voluntary or culpable drunkenness does not exclude impunity, except in cases in which drunkenness is accidental or is caused by force majeure. Psychiatrists are often called into court to give testimony and offer opinions on the mental state of criminals who have committed crimes under the influence of alcohol and other drug use. They evaluate the need for civil intervention in cases in which the psychiatric and neurological consequences of alcoholic consumption impair the civic duties or work capacity of individuals who drink, for instance. In all these cases, it is imperative that the psychiatrist should have ample knowledge of the penal codes and the detrimental effects of alcohol abuse. Recognition of the different criminological aspects of the genesis of crime is an essential subject within clinical and forensic contexts. Other than knowledge of the laws and penal codes, an integrated understanding of the diverse aspects of criminology is also necessary, given that crime is a multifactorial and complex phenomenon. This frequently impedes establishing a direct association between crime, alcohol and illegal drug use.