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Alonso Sala
CRIMINAL LAWYERS
Legal Analysis

The Insanity Defence: Forensic Psychiatry in High-Profile Trials

December 14, 2025Updated: 

Key Takeaways

  • Complete vs incomplete exemption
  • Psychosis and break with reality
  • Insuperable fear
  • Psychiatric internment

Criminal liability requires the capacity to understand the unlawfulness of the act and to act according to that understanding. Art. 20.1 CP exempts anyone who, because of a mental anomaly or alteration, cannot understand the unlawfulness or act accordingly; the incomplete exemption drastically reduces the sentence. Psychosis (a psychotic break, delusions) can ground the exemption, whereas psychopathy is usually treated as fully imputable. Art. 20.6 CP adds the exemption of insuperable fear. A complete exemption for insanity entails acquittal, but almost always a security measure of internment whose duration cannot exceed that of the sentence that would have corresponded.

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In criminal law, guilt requires not only having committed the act (objective imputation) but having done so with the capacity to understand its unlawfulness and to act according to that understanding (subjective imputation). When the accused's mental health is compromised, the defence strategy shifts radically: the goal may not be to deny the fact, but to demonstrate that the client is not criminally responsible. This is the terrain of exemptions and mitigating factors due to mental anomaly or alteration (art. 20.1 CP).

The Great Difference: Psychopathy vs. Psychosis

One of the most common mistakes is confusing the psychopath with the psychotic. For Spanish jurisprudence, the psychopath (antisocial personality disorder) perfectly understands what they are doing; they simply do not care emotionally. Therefore, they are fully imputable and their coldness can even act as an aggravating factor. In contrast, a psychotic break (paranoid schizophrenia, delusions) implies a break with reality. If the accused acted under the imperative of a hallucinatory "voice", they lack volitional freedom. Here lies the expert battle: demonstrating that there was no malice, but illness.

Temporary Mental Disorder and Addictions

A chronic illness is not always required. We defend cases of "outburst or obfuscation" or temporary mental disorders caused by acute consumption of toxins (withdrawal syndrome or full intoxication). The key for the exemption (acquittal) or incomplete exemption (drastic reduction of sentence) to apply is to prove the intensity of the impairment at the exact moment of the events. This requires detailed technical retrospective forensic psychopathology reports.

The Exemption of Insuperable Fear

Article 20.6 of the Criminal Code exempts anyone who acts driven by an "insuperable fear". It is a common defence in cases of domestic violence or in extreme situations where the accused reacts defensively to a real or imagined threat perceived as real. Unlike self-defense, the act is not justified here, but the author is "excused" because, given their situation of psychological terror, other conduct could not be demanded of them ("non-demandability of other conduct").

The Jury Court

In trials with a Popular Jury, psychiatric evidence is critical. The lay jury tends to judge the facts. The defence lawyer's job is to "humanize" the accused and translate complex medical terminology into emotional and understandable language that allows the jury to empathize with the defendant's altered mental state.

Acquittal is Not Freedom: Security Measures

It is vital to be honest with the client and their family. Achieving a complete exemption due to mental insanity entails criminal acquittal, but almost invariably implies the imposition of a security measure of internment in a psychiatric penitentiary center. The duration of this measure cannot exceed that of the prison sentence that would have corresponded, but its execution is different. Our defence extends to the execution phase, fighting for outpatient treatments or internments in external civil centers, much more suitable for therapeutic recovery than psychiatric prison.

Frequently asked questions

Is a psychopath not criminally responsible?

Under Spanish case law, a psychopath (antisocial personality disorder) fully understands what they are doing, even if they feel no emotional concern; they are therefore fully criminally responsible, and their coldness can even operate as an aggravating factor. A psychotic break is different: it involves a break with reality and can ground the exemption.

What is the difference between a complete and an incomplete exemption?

The complete exemption under Art. 20.1 CP leads to criminal acquittal when the mental anomaly or alteration prevents the person from understanding the unlawfulness of the act or acting according to that understanding. The incomplete exemption applies when the impairment is partial and does not fully remove that capacity, producing a drastic reduction of the sentence.

Can intoxication or a withdrawal syndrome exempt someone from criminal responsibility?

A chronic illness is not required. A temporary mental disorder caused by full intoxication or withdrawal syndrome can give rise to the exemption or the incomplete exemption. The key is proving the intensity of the impairment at the exact moment of the events, which requires a retrospective forensic report.

What is the exemption of insuperable fear?

Art. 20.6 CP exempts anyone who acts driven by insuperable fear. Unlike self-defence, it does not justify the act; it excuses the perpetrator because, given their situation of terror, no other conduct could be demanded of them. It is common in extreme situations and contexts of violence.

Does being declared not criminally responsible mean going free?

Not necessarily. A complete exemption for insanity entails criminal acquittal, but it almost always involves a security measure of internment in a psychiatric centre. Its duration cannot exceed that of the prison sentence that would have corresponded, and the defence can fight for outpatient treatment or external centres.

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