The most time-consuming type of annulment is one which investigates whether or not there was a defect of consent in one or both parties. This process is more involved, and looks closely at the family backgrounds of the couple, their experience while dating, the circumstances of the actual wedding, and the early years of marriage.
The reasons (or grounds) for defective consent can vary greatly. Some would include a grave lack of discretion of judgment; consent resulting from force and fear; an intention against permanence of marriage; an intention against having children; an inability to consent to the obligations of marriage because of a serious psychological anomaly, and a consent made subject to a condition about the future.
These annulment cases are usually referred to as formal annulment cases, and they require a serious look at the mindset and intention of a person when the marriage took place.