Mental illness in children, adolescents and young people

Children and young people experience a range of common mental illnesses. Early intervention in childhood and adolescent years can prevent or mitigate potentially lifelong mental illness.

Mental illness in children

Around 14 per cent of children and young people aged 4–17 years are affected by mental illness at some time. This rises to 26 per cent for those aged 16–24. Seventy-five per cent of severe mental illness emerges before the age of 25 and accounts for 70 per cent of the total burden of mental illness among young people.

The earliest disorders to appear include attachment disorders and pervasive developmental disorders (including autism), although persistent and severe distress may be observed in infancy.

By three years of age, common mental disorders start to appear as disruptive behaviours (oppositional defiant disorder and attention deficit hyperactivity disorder) and emotional disorders (anxiety disorders, depression and post-traumatic stress disorder).

The rates and comorbidity of these common disorders in preschool children are similar to those in later childhood.

Children with mental disorders often present to primary care services with physical symptoms. Parents and general practitioners may not always recognise that physical symptoms are signs of emotional stress or mental illness in young children.

Mental illness in young people

Mental illness in young people include high-prevalence disorders such as depression and anxiety, which affect many young people and are of mild to moderate severity, as well as low-prevalence disorders such as psychosis and serious mood and eating disorders.

These severe and complex adult-type mental illnesses and disorders among older adolescents and young adults have a potentially high burden of disease and disability. They require urgent early attention, carefully considered management, and different expertise to that used in responses to more common and less disabling high-prevalence illnesses.

Early onset psychosis in young people is a mental health emergency at this stage of life. While some young people fully recover, others experience various levels of relapse and disability, and some experience an enduring life course of illness.

This population has a high suicide rate. Psychotic disorders need professional and specialist input early in the course of illness.

Psychosis in young people increasingly leads to problematic alcohol and other drug use. This requires an integrated treatment response that addresses both issues concurrently.

Determining assessment and treatment

Services need to be tailored to the type of illness and disorder. This will determine how assessment and treatment should be provided, and what clinical guidelines will be used for interventions.

Specialist services will clarify diagnosis and early management planning to ensure that mental illness is accurately identified and interventions are phase and age specific.

Specialist youth mental health services focus on three priority groups of children and young people:

• those with emerging and potentially severe and complex mental illness who need early direct services. This includes young people with psychoses, mood disorders, personality and substance-use disorders
• those with mild to moderate mental illness may need consultation and shared-care arrangements with primary health, welfare, student support and vocational services
• highly vulnerable young people who need priority access. This includes young people who have experienced trauma, abuse, neglect or family violence. This group can fall into either of the cohorts above, and typically presents with complex psychosocial issues such as homelessness.

Given the fluctuating acuity and course of some disorders, services from primary to specialist care need to respond flexibly to children and young people presenting with a mental illness.