In the Philippines—the only country aside from the Vatican without a divorce law—the "Annulment" process is the primary bridge to marital freedom. However, most Filipinos use the term "Annulment" as a catch-all for what is technically a Petition for the Declaration of Absolute Nullity of Marriage under Article 36 of the Family Code.

Unlike a true annulment (which cancels a valid marriage due to a defect at the start, like fraud or lack of parental consent), a Declaration of Nullity based on Psychological Incapacity posits that the marriage was void from the very beginning because one or both parties were incapable of understanding or fulfilling the essential obligations of marriage.

I. Defining Psychological Incapacity

The law does not provide a rigid medical definition for psychological incapacity. Instead, it is a legal concept. For decades, the courts followed the strict "Molina Guidelines," which required the incapacity to be a "clinical" personality disorder.

However, the landmark 2021 Supreme Court ruling in Tan-Andal vs. Andal fundamentally shifted the landscape.

The Modern Standard (Tan-Andal Doctrine)

Psychological incapacity is now viewed as legal, not medical. You no longer need a psychiatrist to prove a specific clinical diagnosis like "Narcissistic Personality Disorder." Instead, you must prove that a party’s personality structure renders them truly incapable of complying with the essential marital obligations.

To succeed, the petitioner must establish three criteria:

Gravity: The incapacity must be serious enough that the party cannot function as a spouse. Simple "irreconcilable differences," moodiness, or laziness are insufficient.
Juridical Antecedence: The incapacity must have existed at the time of the celebration of the marriage, even if it only became manifest later.
Incurability: In the legal sense, this means the incapacity is so "enduring" or "persistent" regarding a specific partner that it cannot be resolved through intervention within the context of that marriage.

II. Essential Marital Obligations

What exactly is the party "incapable" of doing? Under the Family Code (Articles 68-71), these obligations include:

Living together under one roof.
Observing mutual love, respect, and fidelity.
Rendering mutual help and support.
The joint responsibility of managing the household and caring for children.

III. The Legal Process: Step-by-Step

Navigating a petition under Article 36 is a marathon, not a sprint. The process typically takes two to four years, depending on the court's docket.

1. The Psychological Evaluation

While Tan-Andal says expert testimony is not strictly mandatory, it remains highly recommended. A psychologist interviews the petitioner, witnesses, and (if willing) the respondent to create a Psychological Evaluation Report. This report maps the history of the parties to show how the "personality structure" developed and manifested during the marriage.

2. Filing the Petition

The petition is filed in the Regional Trial Court (Family Court) of the province or city where either the petitioner or the respondent has been residing for at least six months.

3. Collusion Investigation

Because the State protects marriage, the Office of the Solicitor General (OSG) or the Public Prosecutor is tasked with investigating whether the parties "rigged" the case. They ensure that the parties aren't just agreeing to break up because they’re bored; there must be a genuine legal ground.

4. Pre-Trial and Trial

This is the "meat" of the process.

Petitioner’s Testimony: You tell the story of the marriage.
Witnesses: Friends or family members who observed the dysfunctional behavior.
Expert Witness: The psychologist explains the legal incapacity.
Cross-Examination: The Prosecutor/OSG will attempt to poke holes in the testimony to "defend" the bond of marriage.

5. Judgment and the OSG’s Role

If the judge grants the nullity, the OSG may still appeal the decision to the Court of Appeals or the Supreme Court. The marriage is only officially "void" once a Certificate of Finality is issued.

IV. Consequences of the Decree

Once the court declares the marriage void ab initio (from the beginning):

Status: The parties are restored to the status of "single" and can legally remarry.
Children: Children born of a marriage declared void under Article 36 are considered legitimate. Custody is usually decided based on the "Best Interest of the Child" rule.
Property: Since the marriage never legally existed, the property regime (usually Absolute Community of Property) is liquidated. In many cases, co-ownership rules apply.

V. Common Misconceptions

"Infidelity is enough": No. Sexual infidelity is a ground for Legal Separation (which doesn't allow remarriage), not necessarily nullity, unless the infidelity is a symptom of a deeper psychological incapacity to remain faithful.
"It’s just for the rich": While legal and psychological fees are high (often ranging from ₱250,000 to ₱600,000+), it is a standard legal remedy available to anyone who can prove the grounds.
"The other spouse must agree": Actually, the case can proceed even if the other spouse refuses to participate or contests the petition.

Summary Table: Annulment vs. Nullity (Article 36)

Feature	Annulment (Voidable)	Nullity (Art. 36 - Void)
Status of Marriage	Valid until "annulled"	Void from the very beginning
Grounds	Fraud, Force, Impotence, STI	Psychological Incapacity
Prescription	Must be filed within 5 years	No prescription (can be filed anytime)
Result	Remarriage allowed	Remarriage allowed