Criminal behavior refers to conduct of an offender that leads to and including the commission of an unlawful act and can be explained on sociological or anthropological terms or as responding to biological determinants. Criminal behaviors with a psychopathological sub strum require a biological layer of explanation through biological mechanism that involve personality aspect, genetic and hereditary factors, physiologicalalterations, cerebral damage caused by perinatal insults or head trauma or acute intoxication. In fact, genetic, physiological and biochemical factors are casual agents in the same sense as family, social class or neighborhood factors. Some physiological correlates of personality are also related to criminality, especially by individuals with antisocial and psychopathic personalities. Higher threshold for excitability and higher impulsivity accompanied by lower levels of skin conductance, pulse and electroencephalographic makes for excitability than found among normal individuals are found among psychopathic which could explain their thrill-seeking behaviors. Similarly low pulse has been found to be related to regulatory patterns of inhibitory conduct among adolescents, juvenile delinquents and those diagnosed with conduct disorder, according to experts.
Neuropsychological tests could demonstrate cerebral damage, but this is best done with imaging, MRI, PET scans and SPECT examinations have demonstrated frontal lobe damage among extremely violent individuals, serial murderers and non-psychotic personality disorders persons. Cerebral pathology is related to intermittent explosive disorders and frontal lobe insults have been associated with levels of impulsivity which in turn have been related to levels of serotonin. A familiar components has been described relating antisocial behavior, criminality and violence which in turn are related to parental violence, poverty, single parent families and rough neighborhoods. These interfamily variation factors as known in genetic epidemiology, change from family to family but remains constant as a load in a single family. It is not possible, yet to differentiate within members of a family the quantities that could be attributed to the genetic load (genotype) from that attributed to the environment and that result on a particular form of behavior (phenotype).Link and association studies demonstrate that some genetic disorders such as alcoholism, Gilles dela Tourette syndrome and fragile X-syndrome could be related to antisocial behavior and violence. Furthermore, adoption studies of twins indicate that there exists a genetic relation between antisocial personality and alcoholism. Well, the truth is that both genetic and environmental factors do play an important role in a person’s criminal or anti-social behaviors. Twin studies shown that criminal behavior is influenced by both genetic and shared environmentalfactors. Toxic substances are common correlates of criminal behavior either ingested voluntarily or through exposure in the environment. The impact of alcohol on infants in utero resulting in fetal alcohol syndrome or intellectual damage suffered by normally born babies exposed to high levels of lead in the environment are well documented. Developmental delays and injuries to the developing brain are risk factors for criminality. Alcohol has a well –known impact on the frontal lobes which are in charge of inhibitory functions and on the limbic structures in charge of vegetative and instinctive functions. The effect of alcohol and drugs are well known in forensic psychiatry because of violent crimes including sexual attacks committed while intoxicated and the emergence of dissociative and automatic states of mind. It is reported that 42% of arrested individuals are inebriated and 29% are under the effects of drugs at the time of arrest. Furthermore, 57% had used drugs within one month prior to their arrest and 83% of inmates in state prisons and 73% of those in federal prisons had utilized drugs at some time in their lifetime. Some experts have expressed a concern that biological explanations could lead to the complexities of crime. They point out that such way of thinking could distort the truth because of the weight paid to biological facts, could false hopes for easy solutions and apprehensions in the population worse than the actual dangers represented by crime. Myths surrounding biological investigations of crime have retarded the development of this profitable area of research.
Crimes occurs most frequently during the second and third decade of life. Males commit more crimes overall and more violent crime than females. Males appear to be more likely to reoffend. Measures related to arousal such as heart rate and skin conductance are low among criminals. Monomorphic or muscular body type is positively correlated with sexual crimes. Testosterone levels positively correlates to criminal behavior. When controlling for age and sex, strong genetic correlates with criminality. Low monoamine Oxidase activity and low 5-HIAA levels tends to be found among criminals. Monoamine OxidaseA (dubbed the ‘warrior gene ‘in popular press) is strongly tied to an increased tendency towards violent crimes. In addition CDH13, a gene previously tied to increased risk of substance abuse has been tied to violent crime. Ferguson stated “a large percentage of our behavior in terms of violence or aggression is influenced by our biology-our gene-and our brain anatomy. In some countries ethnically/ racially diverse geographical areas have higher crime rates compared to homogeneous area. Some studies on immigrants found higher rates of crime among these populations. Associated factors of criminal behavior also include maternal smoking during pregnancy,low birth weight, child maltreatment, low parent-child attachment, marital discord/family discord, alcoholism and drug use in the family, low parental monitoring/supervision etc. From the above facts of developing criminal behavior among human being, thesolutions of reducing criminal behavior can be taken up promptly by using the reverse actions against the way how criminal behavior originated.