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Truth tests cannot be used as evidence

Narcoanalysis is psychotherapy conducted while a patient is in a sleeplike state induced by barbiturates or other drugs, writes Harish V Nair.

india Updated: Jan 11, 2007 02:49 IST

What is narcoanalysis?

Narcoanalysis is psychotherapy conducted while a patient is in a sleeplike state induced by barbiturates or other drugs, especially as a means of releasing repressed feelings, thoughts, or memories. Thiopentone sodium, also known as the “truth drug”, is commonly used. It is intravenously administered to a patient. According to procedure prescribed by the Directorate of Forensic Sciences, the test is done by a team comprising an anaesthesiologist, a psychiatrist, a clinical/ forensic psychologist, an audio-videographer, and supporting nursing staff. The results include a report from the psychologist and a video recording of the test. The revelations can be verified by polygraph and brain-mapping tests.

What is brain-mapping?

It is a test that stimulates the brain to examine the truth quotient of a subject’s responses. It works on a simple principle — lying leads to activity in the frontal part of the brain: the medial inferior and pre-central areas. During a truthful response, the brain's frontal lobe, temporal lobe and cingulate gyrus gets activated. When lying, more areas of the brain get activated and are picked up as red spots in the brain.

Are statements made during narcoanalysis and brain-mapping admissible as evidence?

The statements have no value before the courts. But the facts disclosed during the tests have evidentiary value if proved by subsequent recoveries. Therefore, investigating agencies use it to carry the probe forward. For example, if Surender reveals during narcoanalysis that he raped a girl and threw her clothes in the drain, the statement does not have any value. But if the clothes are recovered later, it is admissible in the court as evidence.

What is the case against the tests?

Article 20 (3) of the constitution says that one cannot be forced to become a witness against himself. So self-incriminating declarations made under influence of drugs are not admissible as evidence. Critics also say the tests violate fundamental rights.

When were the tests in the news last?

In the Rahul Mahajan drug-snorting case, the trial court allowed the brainmapping of Rahul but it was challenged in the high court. The HC stayed the order after their lawyer said the procedure was “unconstitutional”.

First Published: Jan 11, 2007 02:49 IST