Narco-Analysis
Definition
A technique in which a subject is administered a barbiturate or benzodiazepine drug (commonly sodium pentothal or midazolam) to induce a hypnotic state, in the belief that this reduces the capacity for deliberate falsehood and allows investigators to elicit truthful disclosures. Scientific evidence for the reliability of disclosures made under drug influence is weak, and the procedure carries medical risks.
- Common drugs
- Sodium pentothal (thiopental) or midazolam
- Effect
- Induces a drowsy, disinhibited hypnotic-like state
- Also called
- Truth serum test, narcoanalysis
- Legal status in India
- Barred without subject consent (Selvi v. State of Karnataka, 2010)
- Reliability
- Not accepted as substantive evidence in most jurisdictions
Common questions
Why do courts reject narco-analysis results as evidence?+
The drugged state impairs judgment and increases suggestibility, so a subject can produce confabulated or false statements that feel true to them. Courts in India, the US and UK treat any resulting statement as involuntary and unreliable rather than as a fact-finding shortcut.
Can narco-analysis still be used at all in an investigation?+
Some jurisdictions allow it only as an investigative lead with the subject's informed consent and medical supervision, never as evidence presented to a jury or judge. Any information obtained must still be independently verified before it has evidentiary value.
Related terms
- Polygraph
- An instrument that simultaneously records multiple physiological channels including blood pressure, respiration rate, galvanic skin response, and sometimes heart rate while the...
- Article 20(3) (Indian Constitution)
- The constitutional provision that states no person accused of any offence shall be compelled to be a witness against themselves. India's Supreme...
- BEOS
- Brain Electrical Oscillation Signature profiling, developed by Champadi Raman Mukundan and validated 2003 at NIMHANS Bangalore; uses 32-channel EEG to classify probes...
- Brain Electrical Activation Profile (BEAP / P300 Test)
- A method that uses electroencephalography (EEG) to detect the P300 event-related potential, a positive-going brainwave that occurs approximately 300 milliseconds after a...
- CQT
- Control Question Test (Reid/Keeler technique): compares physiological response to relevant questions with response to control (probable-lie) questions; the dominant US polygraph format.
- Criminal Profiling
- The inference of an unknown offender's likely characteristics from crime scene behaviour, victimology, and case details. Also called offender profiling, criminal investigative...
- FBI BAU
- Behavioral Analysis Unit at the FBI Academy, Quantico, evolved from the Behavioral Science Unit set up by Howard Teten and Pat Mullany...
- GKT / CIT
- Guilty Knowledge Test, also called Concealed Information Test (Lykken, 1959): tests whether the subject recognises crime-specific details only the perpetrator would know;...
- Modus Operandi
- How the offender commits the crime: the functional behaviour needed to complete it; evolves with experience and feedback.
- Organised vs Disorganised
- The BSU dichotomy proposed by Ressler and Douglas, classifying offenders by scene presentation. Organised scenes show planning; disorganised scenes show chaos. The...
- P300
- Event-related brain potential occurring about 300 ms after a meaningful stimulus; Lawrence Farwell's 'Brain Fingerprinting' uses P300 amplitude to flag concealed recognition...
- Section 23, Bharatiya Sakshya Adhiniyam 2023 (Discovery Rule)
- The provision (successor to Section 27 of the Indian Evidence Act 1872) under which information given by a person in police custody...
Explained in these topics
- Criminal Profiling, Polygraphy, Narco-Analysis and Brain MappingForensic interview conducted while the subject is in a drug-induced semi-conscious state (typically sodium pentothal); rests on the disputed claim that the sed...
- Narco-Analysis, Polygraph and Brain Mapping in Law