Adult Guardianship vs Supported Decision-Making: The Legal Decision at Age 18 and Beyond

The day your child turns 18, something quiet and significant happens in the eyes of the law: they become an adult. And you are no longer their legal decision-maker, regardless of their disability. The school can no longer share records with you without their consent. The doctor cannot legally discuss their medical care with you. The bank will not let you sign for them. For many lifelong caregivers, this comes as a shock, because the day-to-day caregiving has not changed at all, even as the legal ground shifted overnight.

For decades, the standard response was to file for adult guardianship. Guardianship is a court order that legally appoints a parent (or other adult) as the decision-maker for the now-adult child in some or all areas of their life: medical, financial, residential, educational, and personal. Once granted, guardianship usually lasts for the rest of the disabled adult's life unless modified by the court. It is a powerful tool, and for some families with a child who genuinely cannot make any decision safely (for example, a person with profound intellectual disability or severe traumatic brain injury), it remains the right answer.

But for many people with intellectual or developmental disabilities, guardianship goes further than needed. It removes legal rights that the person could keep with support: the right to vote, the right to marry, the right to sign a contract, the right to make choices about their own medical care. Disability self-advocates and organizations like SARTAC, the National Council on Disability, and The Arc have spent the last decade documenting how broad guardianship can harm the person it is meant to protect, by stripping them of decisions they could make with help.

A newer model, called Supported Decision-Making (SDM), preserves the adult's legal rights while formalizing the network of people who help them make decisions. Under SDM, the disabled adult retains their full legal status. A written agreement (called a Supported Decision-Making Agreement) lists the people they have chosen as their supporters, the areas where they want help, and how decisions get made together. Banks, doctors, schools, and service providers in states that recognize SDM accept the agreement the way they would accept a power of attorney.

As of 2026, more than 20 states have passed laws recognizing Supported Decision-Making, and more states are adopting it each year. Even in states without a formal law, families can write SDM agreements that have practical value. The key shift is that SDM is the default, and guardianship is reserved for cases where SDM genuinely cannot work.

The right answer for your family depends on your adult child's specific capacity, the systems they interact with, and the supporters available to them. There is no single right answer for every family. What matters is that the choice be considered carefully, not made by default.

(Sources: National Resource Center for Supported Decision-Making at supporteddecisionmaking.org; National Council on Disability — Beyond Guardianship report; The Arc Position Statement on Self-Determination and Decision-Making Supports; SARTAC self-advocate resources)