Insanity Defence for CLAT: M'Naghten and Intoxication

📑 On this page

⚡ The short answer

Nobody is guilty if, at the time of the act, unsoundness of mind left him incapable of knowing what he was doing, or that it was wrong or illegal. That is legal insanity; a diagnosis alone isn't enough. Intoxication excuses on the same test, but only if involuntary: spiked or forced. Choosing to drink never excuses.

🎬 The 30-second story

The Holi thandai

“Plain thandai, bro. Totally safe.”

🥛

Rohan

Aarav has never touched bhang. Rohan secretly loads his glass.

“The shop window is a portal! I have to get through!”

🌀

Aarav

Hallucinating, Aarav smashes Kabir's shop window.

“Four glasses, then I'll tell Kabir what I really think.”

🍶

Aarav

A month later, Aarav knowingly drinks bhang and smashes it again.

“Both times he was out of his mind. Both times I pay?”

🪟

Kabir

Kabir complains about both nights.

Tara's ruling: Night one: no offence. The bhang went in without his knowledge and he couldn't grasp what he was doing. Night two: guilty. He chose to drink, so the law treats him as sober.

What does the insanity defence actually say?

Every crime needs a guilty mind. If illness has switched off a person's understanding, there's no mind to blame. The law excuses him not because he's ill, but because he couldn't understand.

🧮 The formula

The insanity defence in one line

🧠

Unsoundness of mind

the cause

⏱️

At the time of the act

not before, not after

❓

Incapable of knowing

of the act or its wrongness

🛡️

No offence

Note the or: two exits. Either he didn't know the nature of the act (he thought he was cutting a log, not a person), or he knew what he was doing but couldn't know it was wrong or illegal.

📌 How a CLAT passage words it

'Nothing is an offence which is done by a person who, at the time of doing it, by reason of unsoundness of mind, is incapable of knowing the nature of the act…' Underline: at the time, incapable, knowing.

Is every mentally ill person protected? Legal vs medical insanity

No, and this is the most tested trap. A doctor asks, 'Is he ill?' A court asks, 'Could he understand what he was doing, and that it was wrong?' Many people with a genuine diagnosis still can.

⚔️ Side by side

Medical insanity vs legal insanity

🩺Medical insanity

Does the person have a mental illness?

•Decided by doctors

⚖️Legal insanity

Could he understand the act or its wrongness?

•Decided by the judge

Test	Medical insanity	Legal insanity
Moment that matters	Any time	The moment of the act
Enough for acquittal?	No	Yes

Medical evidence helps prove legal insanity, but it doesn't replace it.

🎚️ The scale

Where does the defence kick in?

← Fully liableNo offence →

Rage or jealousy

e.g. He 'saw red' and stabbed his rival.

Odd or eccentric

e.g. Talks to plants, but planned the theft carefully.

Diagnosed, but aware

e.g. Ill, but hid the weapon and lied to the police.

Couldn't understand

e.g. Believed he was killing a demon, not a man.

⚠️ The 'he was always a bit off' trap

CLAT loves a character who is 'unstable' or 'on medication' and then plans the act, waits and runs. Planning, hiding and fleeing show he knew it was wrong. The defence fails.

What is the M'Naghten test?

The test traces to an 1843 London shooting. After the accused was acquitted as insane, the House of Lords asked the judges to state the law. Their answers, the M'Naghten Rules, still shape the Indian test.

1
Everyone is presumed sane
Until the contrary is proved.
2
The accused must prove it
That a disease of the mind left him unable to know the act's nature or that it was wrong.
3
If he knew, he's liable
However disturbed he was otherwise.
4
Partial delusion: treat it as true
Thought the man was about to kill him and struck first? Excused. Thought the man had insulted him and killed for revenge? Liable, because revenge is a crime even on his imagined facts.

Why does the time of the act matter so much?

Illness can come and go, or start only after the crime. The defence looks at one moment: the act. Courts read it from conduct before, during and after.

🕒 Timeline

What the court looks at, moment by moment

📅
Before

Motive and history

A clear motive or plan points to a working mind; a long treatment record points the other way.
⚡
During

How the act was done

Choosing a weapon or a moment with no witnesses suggests understanding.
🏃
Right after

Flight, lies, confession

Running, hiding evidence or calm answers to the police show he knew it was wrong.
🏛️
At trial

A separate question

Illness at trial only delays the trial. It proves nothing about the act.

Who has to prove it, and how strongly?

The prosecution always proves the crime beyond reasonable doubt. The accused proves insanity only on a balance of probabilities. Even if he falls short, evidence of illness can raise a reasonable doubt about his guilty mind and earn an acquittal.

ℹ️ Acquitted isn't the same as walking free

He is usually ordered into safe custody or a mental health facility, or handed to a relative who gives security to look after him.

When does being drunk or high excuse a crime?

Same test as insanity, plus one gate. The drink or drug must have left him incapable of knowing the act or its wrongness, and been taken without his knowledge or against his will. Chose to take it? The law won't listen.

⚔️ Side by side

Involuntary vs voluntary intoxication

🧪Involuntary

He didn't know, or didn't agree

•Spiked drink
•Forced at knifepoint

🍺Voluntary

He chose to drink

•Drank under persuasion
•Drank 'for courage'

Test	Involuntary	Voluntary
Defence?	Yes, if incapable of knowing	No
How the law treats his knowledge	As it actually was	As if he were sober

Let him who sins when drunk be punished when sober.

🧭 Decision flow

Does intoxication excuse this act?

❓ Was the intoxicant taken without his knowledge or against his will?

Persuasion and peer pressure don't count.

Yes →

❓ Did it leave him incapable of knowing the nature of the act, or that it was wrong?

Yes →

No offence

Whoever spiked it may be liable instead.

No →

Liable: tipsy but still aware

No →

❓ Has long drinking caused a disease of the mind that left him unable to understand?

A lasting illness, not one night.

Yes →

Insanity defence may apply

No ↓

❓ Was he too drunk to form the specific intention the crime needs?

Yes →

May cut the charge down, never a full excuse

No →

Fully liable, treated as sober

Drunk but still guilty: knowledge vs intention

For a voluntary drinker the law splits the guilty mind. Knowledge is imputed as if he were sober. Intention is inferred from the facts, keeping his drunkenness in view. Drink that merely makes him hot-headed changes nothing: he's presumed to intend the natural consequences of his acts.

🧩 At a glance

Five intoxication facts CLAT can build

🥤Spiked drink

Without his knowledge. Defence if he couldn't understand.

🔪Forced to drink

Against his will. Same as spiking.

🗣️Peer pressure

He still chose to drink. No defence.

💪Dutch courage

Drank to nerve himself for the crime. No defence.

🏥Drink-caused illness

Years of drinking caused a disease of the mind. Argue insanity.

Can you defend yourself against an insane or drunk attacker?

Yes. His defence is personal: it erases his guilt but doesn't make his attack lawful. You keep the same right of private defence you'd have against a sane, sober attacker.

🔗 Who owes whom

Two defences, one fight

Insane attacker → Person attacked: attacks with a knife
Person attacked → Insane attacker: strikes back — private defence still available
Court → Person attacked: no offence either

Also: a person too insane or intoxicated to understand cannot give valid consent.

Which cases shaped insanity and intoxication?

🎩

Landmark case · 1843 · House of Lords (answers of the judges)

M'Naghten's Case

📋

What happened

Convinced the government was persecuting him, Daniel M'Naghten set out to shoot Prime Minister Robert Peel and killed Peel's secretary by mistake.

❓

The question

When does a disease of the mind excuse a killing?

🔨

What the court held

Acquitted as insane. The judges then said a person is excused only if he couldn't know the act's nature or that it was wrong.

What CLAT takes from it: The root of the 'incapable of knowing' test.

🔒

Landmark case · 1964 · Supreme Court

Dahyabhai Chhaganbhai Thakker v State of Gujarat

📋

What happened

A man killed his wife in their bolted bedroom. Weeks earlier he'd asked her father to take her away. Next morning he answered the police calmly and offered to confess. Insanity was pleaded only at trial.

❓

The question

Was he legally insane at the time of the killing?

🔨

What the court held

No. Read from conduct before, during and after the act, the plea was an afterthought. Illness during the trial didn't prove illness at the act.

What CLAT takes from it: The time of the act counts. The accused proves insanity on a balance of probabilities; a reasonable doubt on mens rea can still acquit.

🔫

Landmark case · 1956 · Supreme Court

Basdev v State of PEPSU

📋

What happened

A retired army jamadar, very drunk at a wedding, asked a teenage boy to give up a seat. The boy didn't move, so he shot him dead.

❓

The question

Did heavy voluntary drinking reduce murder to a lesser offence?

🔨

What the court held

No. He chose his seat, walked unaided, tried to flee and begged forgiveness. His mind could form the intention.

What CLAT takes from it: Knowledge is presumed as if sober. Only drink that makes intention impossible helps, and only to lower the charge.

How did CLAT ask about insanity and intoxication?

📝 Asked in CLAT 2019 · Q76 Insane attacker

Principle: Nothing is an offence which is done in the exercise of the right of private defence. Nothing is an offence which is done in madness. Facts: A, under the influence of madness, attempts to kill B. B to save his life kills A.

No separate question in the paper: pick the option that correctly applies the principle.

AA has committed the offence of attempt to murder

BA has committed an offence of being mad

CB has committed an offence

DB has not committed an offence

Reveal answer + reasoning

Answer: D

Our solution (no official key exists for 2019). Apply each principle to its own person. A acted in madness: no offence. B killed to save his life: private defence. A's insanity removes A's guilt, not the danger B faced.

Why the others fail

A — Nothing done in madness is an offence.
B — Being mad isn't an offence at all.
C — Saving his own life is exactly what private defence covers.

📝 Asked in CLAT 2019 · Q97 Persuaded to drink

Principle: Nothing is an offence if it is done under intoxication and the person committing the offence was incapable to understand the nature of the Act. Intoxication should be without knowledge or against the will of the person. Facts: A, B and C were having a party in Bar where A persuaded B and C to take alcoholic drinks. On the persistent persuasion B and C also consumed alcohol along with A. B and C had never consumed alcohol before. After intoxication, there was some argument between B and C where C pushed B with full force causing serious injury to B.

No separate question in the paper: pick the option that correctly applies the principle.

AC is liable

BC is not liable because he was intoxicated

CA is liable because A persuaded them to consume alcohol whereas they had never consumed alcohol

DA and C both are liable

Reveal answer + reasoning

Answer: A

Our solution (no official key exists for 2019). C fails the second condition. However persistent A was, C knew it was alcohol and chose to drink. Persuasion isn't 'without knowledge' or 'against the will', so C answers for the push.

Why the others fail

B — Intoxication alone isn't enough; it had to be involuntary.
C — A didn't spike or force anything, and persuading isn't pushing.
D — Nothing makes A liable for C's push.

Quick check: myths and a five-question quiz

💥 Myth vs fact

Traps students fall for

🙅 Myth

A psychiatrist's diagnosis wins the insanity defence.

Tap to bust it →

✅ Fact

It's evidence, not the test. Could he know what he was doing, or that it was wrong?

🙅 Myth

If he was drunk out of his mind, he isn't responsible.

Tap to bust it →

✅ Fact

Only if the drink was spiked or forced. Chosen drink means he's treated as sober.

🙅 Myth

You can't use force against someone who is insane.

Tap to bust it →

✅ Fact

You can. His insanity excuses him, not his attack.

🙅 Myth

Insane at trial means insane at the crime.

Tap to bust it →

✅ Fact

Illness at trial only postpones the trial.

🎯 Quick quiz

Insanity and intoxication: test yourself

0 / 5

Rohan secretly laces Kabir's juice with a strong drug at a wedding. Kabir, confused, mistakes a guest's phone for his own and walks off with it.

Q1. Is Kabir liable?

Aarav plans to beat up a rival, downs half a bottle of whisky 'to get the nerve', then attacks.

Q2. Is Aarav liable?

A colleague on medication for severe anxiety fudges the accounts for three months to hide a theft, deleting the logs each time.

Q3. Can he claim insanity?

In a psychotic episode, a man chops at what he believes is a fallen tree. It's a sleeping traveller, badly injured.

Q4. Which is correct?

Rohan commits a clear, planned burglary. Months later, awaiting trial, he has a breakdown and can't follow proceedings.

Q5. What follows?

🎯 Insanity and intoxication in a nutshell

Legal insanity: incapable of knowing the act, or that it's wrong. A diagnosis alone fails.
Only the mind at the time of the act counts, read from conduct.
Presumed sane; the accused proves it on a balance of probabilities.
Intoxication excuses only if spiked or forced and it destroyed understanding.
Voluntary drinkers are treated as sober for knowledge.
You can still defend yourself against an insane or drunk attacker.

📎 Good to know, not to memorise

Insanity: s.84 IPC / s.22 BNS 2023. Involuntary intoxication: s.85 IPC / s.23 BNS. Voluntary intoxication: s.86 IPC / s.24 BNS.
Private defence against such a person: s.98 IPC / s.36 BNS. Their consent isn't consent: s.90 IPC / s.28 BNS.
Burden on the accused: s.105 Evidence Act / s.108 BSA 2023. Safe custody after acquittal: BNSS 2023, Chapter XXVII.
'Legal, not medical, insanity': Hari Singh Gond (2008), Surendra Mishra (2011). Insanity won in Shrikant Anandrao Bhosale (2002).

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Frequently asked questions

What is the difference between legal insanity and medical insanity?

Medical insanity means a diagnosed mental illness. Legal insanity is narrower: the illness must have made him incapable, at the time of the act, of knowing what he was doing or that it was wrong. Only legal insanity is a defence.

What are the M'Naghten Rules in simple words?

Everyone is presumed sane; the accused must prove a disease of the mind left him unable to know the nature of his act or that it was wrong; and a partial delusion is judged as if the imagined facts were true.

Is drunkenness a defence to a crime in India?

Only involuntary drunkenness: a drink or drug taken without his knowledge or against his will that left him unable to understand his act. If he chose to drink, he is treated as having a sober man's knowledge.

If a friend persuades me to drink, is my intoxication involuntary?

No. You knew what you were drinking and chose it. Involuntary means spiked or forced. CLAT 2019 tested exactly this.

What happens to a person acquitted on the ground of insanity?

He isn't simply released. The court can order him into safe custody, including a mental health establishment, or hand him to a relative who gives security to look after him.