In the Philippines, where absolute divorce remains legally unavailable for non-Muslim citizens, the primary methods for dissolving or invalidating a marriage are Annulment and the Declaration of Nullity. While these terms are often used interchangeably in casual conversation, they represent distinct legal concepts under the Family Code of the Philippines.

I. Understanding the Legal Distinctions

Before initiating legal action, it is crucial to distinguish between a Void marriage and a Voidable marriage.

Declaration of Absolute Nullity (Void Marriages): These marriages are considered non-existent from the beginning (void ab initio). They never had any legal effect because they lacked essential or formal requisites or violated public policy.
Annulment (Voidable Marriages): These marriages are considered valid and binding until they are set aside by a court decree. The grounds for annulment usually involve a defect in consent present at the time of the wedding.

II. Grounds for Annulment (Article 45, Family Code)

Under Article 45 of the Family Code, a marriage may be annulled for any of the following causes existing at the time of the marriage:

Lack of Parental Consent: If either party was between 18 and 21 years old and the marriage was solemnized without the consent of the parents or guardians.
Unsound Mind: If either party was of unsound mind at the time of the marriage, unless they freely cohabited after coming to reason.
Fraud: Consent obtained through fraudulent means, such as:
- Non-disclosure of a previous conviction of a crime involving moral turpitude.
- Concealment by the wife of the fact that she was pregnant by another man.
- Concealment of a sexually transmitted infection (STI).
- Concealment of drug addiction, habitual alcoholism, or homosexuality/lesbianism.
Force, Intimidation, or Undue Influence: If consent was obtained through external pressure that prevented the party from acting freely.
Physical Incapacity: If either party is physically incapable of consummating the marriage (impotence) and such incapacity appears to be incurable.
Serious and Incurable STI: If either party was afflicted with a sexually transmitted infection found to be serious and appears to be incurable.

III. Declaration of Absolute Nullity (Articles 35, 36, 37, and 38)

Most cases in the Philippines are filed under Article 36, which covers Psychological Incapacity.

Article 36: Psychological Incapacity

A marriage is void if one or both parties were psychologically incapacitated to comply with the essential marital obligations (mutual love, respect, support, and fidelity) at the time of the celebration, even if the incapacity becomes manifest only after the solemnization.

Note on Jurisprudence: Following the landmark Supreme Court ruling in Tan-Andal v. Andal (2021), psychological incapacity is no longer viewed as a medical or clinical illness. It is now treated as a legal concept that does not require a formal diagnosis by a psychiatrist, though expert testimony remains highly persuasive.

Other Grounds for Nullity:

Article 35: Absence of any essential/formal requisite (e.g., no valid marriage license, unauthorized solemnizing officer).
Article 37: Incestuous marriages (e.g., between ascendants/descendants, brothers/sisters).
Article 38: Marriages void for reasons of public policy (e.g., between step-parents and step-children, or cousins).

IV. The Legal Process: Step-by-Step

The process for annulment or declaration of nullity is a rigorous judicial procedure that typically takes several years to conclude.

1. Preparation and Filing of the Petition

The petitioner (the spouse filing the case) must hire a lawyer to draft and file a verified Petition for Annulment/Nullity in the Regional Trial Court (RTC) of the province or city where either the petitioner or the respondent has resided for at least six months.

2. Summons and Answer

Once filed, the court issues a Summons to the respondent spouse. The respondent has a period (usually 15 to 30 days) to file an Answer. If no answer is filed, the court cannot immediately declare a default; instead, it triggers an investigation.

3. Collusion Investigation

The court will order the Public Prosecutor (Office of the Solicitor General’s representative) to conduct an investigation to ensure that the parties have not "staged" the case or agreed to the annulment (as "collusion" is strictly prohibited).

4. Pre-Trial Conference

The parties and their counsels meet to simplify the issues, stipulate facts, and limit the number of witnesses. This is a mandatory stage.

5. The Trial

This is the most intensive phase. Evidence is presented through:

Testimony of the Petitioner: Regarding the history of the marriage.
Expert Witnesses: Often a psychologist or psychiatrist who analyzes the "root cause" and "gravity" of the psychological incapacity.
Corroborating Witnesses: Friends or family who can attest to the marital breakdown.

6. Judgment

If the court finds the evidence sufficient, it issues a Decision granting the annulment. However, the case is not over yet. The Office of the Solicitor General (OSG) may appeal the decision to the Court of Appeals.

7. Registration and Finality

Once the decision is final and executory, a Decree of Annulment/Nullity is issued. This must be registered with the Civil Registrar where the marriage was recorded and the Philippine Statistics Authority (PSA).

V. Effects of the Decree

The issuance of a final decree has significant legal ramifications:

Status: The parties are restored to the status of "Single" and can legally remarry.
Property: The community property or conjugal partnership is liquidated and partitioned.
Children: Children of marriages annulled under Art. 45 or declared void under Art. 36 are considered legitimate. Custody is usually determined based on the "Best Interest of the Child" rule.
Support: The court may order provisions for spousal or child support.