A research paper, Young adult carers: making choices and managing relationships with a parent with a mental illness, published by the University of East Anglia, reveals there is a "clear need" for more support for these young people as they approach 18.
It claims transition assessments, which could combine practical support both for the parent and emotional support for the young carer, are rarely carried out.
The findings, published in the journal Advances in Mental Health, argue that such assessments are vital to help support young people with key challenges they are facing as a result of their caring responsibilities.
These include education and employment, relationships with partners, becoming a parent, making choices within their lives and maintaining boundaries with parents.
Dr Kate Blake-Holmes, a lecturer in social work who led the research team, stressed the importance of councils fulfilling their statutory duty to carry out transition assessments for young carers.
"We need to push for these assessments to be done and to be having conversations with young people.
"Everything points towards the patient, which is understandable, but we also need to include young carers in decision-making and meetings about their parents.
"They are the ones living with them and responding to crises, yet there is a fear of discussing issues with young carers because services feel it is inappropriate," she said.
Blake-Holmes said the term "young carer" could imply the role stopped once the child reached maturity, but added that care for parents often continued into adulthood.
"However, as young carers reach the age of 18 the acknowledgement and support for their needs falls away in many areas.
"This study extends our knowledge of young carers' experiences and support needs during the transition to adulthood and suggests the need for services to support parents so that young adult carers are able to make choices about their own lives," she said.
The research involved interviews with 20 people, aged from 19 to 54, who had cared or are continuing to care for a parent suffering from a long-term mental illness.
The study found one young person had to leave university to care for her mother, while others were not able to follow their desired career paths due to their caring commitments.
Several participants had difficulties forming and maintaining relationships with partners.
Others chose not to have children based on their experiences of parental mental illness or for those who did, were worried about balancing their children's needs with those of their parents.
Blake-Homes said caring for a parent was not in itself detrimental but dangers could arise if the level of care provided and the role and responsibilities taken on by a child fall beyond reasonable expectations.
"If the child takes on an adult role beyond their developmental years, it can negatively impact their own needs, coping skills and resilience," she said.
While some individuals drew strength from their adversity, Blake-Holmes said emerging adulthood could be more complex for young adult carers who may have "grown up fast" in certain areas while their emotional and psychological growth could have been delayed in others.