There is the chapter “Disruptive，Impulse-Control，and Conduct disorders” on the DSM-5 compiled by the American Psychiatry Association. It is recognized that the disorders cited in the category develop as they affect each other with the passing of time，and the process is called “DBD march.” Those who have gone through the DBD march have the potential to show antisocial behavior such as delinquency and crime. This paper reviews the DBD march and then introduces a case example of the process. A number of attention-deficit and disruptive behavior disorders peculiar to the Attention-Deficit/Hyperactivity Disorder，Oppositional Defiant Disorder，Conduct Disorder and Antisocial Personality Disorder periods are sorted out based on this case，and consideration is given to how to deal with those disorders.

Only a few criminal psychology studies have investigated animal abusers, and there is little evidence in Japan. Nevertheless, it is often stated that “animal abuse is a sign of future atrocious crimes such as homicide”. Many studies on this topic have been conducted internationally. The classical theories for mechanism of animal abuse are various: ‘social learning theory (Akers, 1985),’ ‘moral disengagement (Bandura, 1990),’ and ‘general strain theory (Agnew, 1992).’ Macdonald (1963) proposed the ‘Macdonald triad’ of risk factors in children, including animal abuse, enuresis, and fire setting that can escalate in the future to interpersonal violence and homicide. The ‘graduation hypothesis’ similar to Macdonald’s triad, assumes that the object of children’s aggression changes from animals to humans. However, after the 2000s, the graduation hypothesis has been replaced by the ‘deviance generalization hypothesis,’ postulating that children with a history of animal abuse are apt to conduct various criminal acts in the future. Furthermore, recent researches have supported ‘LINK’ that animal abuse is deeply related to child abuse and domestic violence. The author emphasized the critical need to conduct criminal psychology studies on animal abuse in Japan and discussed research methods.