Mental Abnormalities Include: (a) Mental Deficiency, and (b) Mental Disease.

Mental Abnormalities Include: (a) Mental Deficiency, and (b) Mental Disease.

Mental Deficiency

Mental deficiency or retardation implies subnormal intelligence, i.e., lack of mental development or low intelligence level (i.e., IQ of less than 75). A person with an IQ of more than 75 is considered a mentally normal person while a person with an IQ of 50 to 70 is called a moron, with 20 to 50 is called an imbecile and with less than 20 is called an idiot. A person with a low IQ is said to be a mentally deficient person, i.e., a person with incomplete development of intelligence.

The development of normal social relationships and performing one’s roles depends upon a person’s ability to adopt himself to his environment and to maintain existence independently of external support.

This, in turn, depends upon one’s IQ Idiots (with a mental age of a child under three years) and imbeciles (with a mental age of a child of 3-7 years) are incapable of managing themselves or their affairs but they are physically strong enough to be dangerous when provoked or frustrated.

Morons (with a mental age of a child of 7-12 years) often have a normal appearance, yet they require care and supervision. In the absence of proper care and control, the morons come to be involved in such crimes as theft, vagrancy, drunkenness, sexual offences and so forth.

Their indulgence in these anti-social behaviour Patterns is due to the fact that they are confused, emotionally unstable or easily exploited by others. But it cannot be said that all mentally deficient persons indulge in crimes.

Manual Shulman’s (Journal of Criminal Law and Criminology, March-April 1951: 763-81) evidence indicates that only a small proportion of mentally deficient persons are delinquent or criminal, and that the offenders and the general population have about the same distribution of intelligence levels.

Thus, like physical defects and personality conflicts, low intelligence is also described as a factor in criminal behaviour. However, it may be a major factor in one particular case but it is never the only factor in crime.

Mental Disease

Mental disease or mental disorder is defined as “a state of mental imbalance or derangement which prevents a person from assuming responsibility for his own support or causes him to be a positive menace to the safety of the community.”

Mental disease refers to a mind that has developed normally, almost always to maturity, but has become disordered or deranged. Mental disease is distinguished from insanity, which is a legal term. An insane person is considered to be incapable of having any criminal intent. The mental disease may either be of psychosis type or neurosis type.