In this chapter I will explore current ideas on the value of early intervention for young people between the ages of 12 and 24 years, arguments for and against establishing a youth mental health service stream and describe the elements of such a service. The chapter finishes with short descriptions of some youth health and mental health services in Australia. While there may be reference to specific illnesses, early intervention approaches for specific illnesses are addressed in other sections of this book and this chapter addresses service delivery across diagnoses. This chapter focuses on the 12–24 years age-band rather than on the usual adolescent age-band (12–18 years). There is increasing support for the argument that the health and developmental needs of all 0–12 year olds differ sufficiently from adolescents and young people to justify separate services. Those aged between 12 and 24 years are emerging adults who are sexually mature, are in the final stages of their educational career or the first stages of their employment career, are embarking on socially accepted adult activities such as using alcohol and tobacco and commencing intimate relationships [1]. As society changes and the adolescent stage effectively lengthens with a longer period of dependence on family and longer periods preparing for a workforce, the traditional Child and Adolescent Mental Health Services (CAMHS) cut-off point of 18 years of age is less suited to older adolescents and young adults. As will be argued below, young people require treatment models that differ substantially from those suitable for children and older adults.

Mental ill-health is the largest contributor to the health burden of young people. The arguments in favour of increased attention to earlier intervention for young people with mental illness are therefore now well established. In a recent Access Economic report in Australia, it is estimated that 24.3% of all Australians between 12 and 24 years of age suffered from a mental disorder in 2009 [2]. There is also evidence that the prevalence of mental illness in young people in Western societies is increasing and that the age of onset of mental illnesses is decreasing. There are many hypotheses put forward to explain this. Increasing use of drugs and alcohol at earlier ages, sociological changes in relation to the protective role of families and independence at a younger age, decreasing levels of exercise, smoking and dietary factors may all contribute [3–5]. The peak onset for severe mental illnesses is in youth: a recent American study reported that half of all life-long mental disorders start by 14 years of age, and three-quarters by 24 years of age [6].

As might be expected, the cost to society is enormous. The Access Economics report referred to above estimated that the financial cost for each young person affected by mental illness in Australia equates to AU$10,544 per annum, with the majority of this cost due to lost productivity because of higher unemployment, absenteeism and premature death [2]. Of great concern is the National Survey of Mental Health and Well-being Study Data, which shows that only 25% of young people and only 15% of males, aged 16–24 years who have a mental illness receive any treatment compared with 35% of the total population with mental illness [7]. Barriers to access and reluctance to access treatment in youth, a period of important growth and developmental milestones including educational attainment, career and family building, are particularly detrimental. Young adults with mental illness are at greater risk of suicide, self-harm and substance addiction. In addition, illness interrupts the attainment of critical age related developmental milestones [8]. Thus, at the time of greatest vulnerability and risk, when perhaps most could be done to prevent the development of more serious illness, young people frequently fail to access other primary care or specialist services for mental health care.

The meaning of early intervention may seem self-evident; however, it needs to be carefully considered before conclusions can be reached about the effectiveness, including cost-effectiveness, of early intervention, the dangers associated with early treatment and approaches to the most effective design of services for the early stages of illness. The rationale behind early intervention is that, particularly for serious disorders such as schizophrenia, bipolar disorder and eating disorders, the longer a person goes untreated the greater the risk of psychosocial consequences due to disruption of education, family stress or breakdown, loss of friendships, use of drugs and alcohol to self-medicate, stigma and disruption of personality development. It is also increasingly understood that there is an active process of neuroprogression in major psychiatric disorders with structural brain changes and neurocognitive consequences [9]. With psychosis, the period between first experiencing symptoms and receiving treatment is referred to as the duration of untreated psychosis (DUP) and its reduction is a major aim of early intervention and specialised services are provided focusing on recovery as early as possible [10]. In addition, it makes sense that families and other carers are provided with an explanation (re-presented and repeated as necessary) and support from specialist health providers as early as possible rather than being left confused, distraught and uninformed which is too often the case.

Early intervention refers to the use of interventions in those displaying the early signs and symptoms of a mental health problem or disorder and contrasts with interventions around the early signs of recurring mental disorder, best referred to as relapse prevention or reduction [11, 12]. Early intervention is described as the ‘fuzzy interface’, between indicated prevention and case identification, and occurs at the point on the pathway to a mental disorder where there are signs and symptoms suggesting an at-risk mental state or indicating a first episode of mental illness. Early intervention must start with early identification, which may in turn mean seeing many people with symptoms that prove to be transitory and not indicative of the development of more serious disorder. Of course this is made much more difficult by the fact that in clinical practice, particularly with young people, symptom complexes are often transient and even when the individual is destined to develop a serious disorder, it is often extremely difficult or impossible to identify the trajectory or the length of time involved during the prodromal phase. Early identification is also complicated by the more diffuse and nonspecific nature of early forms of many disorders. Supporters of early intervention for psychosis argue that all young people with symptomatology should be offered help (whether in schools or workplace, primary care or specialist care) and the models of care which allow for this will, in turn, facilitate early identification and treatment of the minority of people who are on a trajectory to severe illness.

The major sources of disagreement between those who favour early intervention in psychosis and those who do not are whether or not prodromal illness can be identified and ought to be treated (if indeed that is possible) and whether a focus on early intervention for young people has led to resources being drained away from other mental health services where the evidence base is argued to be stronger. Critics of early intervention in the prodromal phase argue that services designed to offer help to all who present with symptoms may lead to ‘pathologising’ adolescents, increasing the risk of using medications with serious side effects when there is no illness, and wasting money that could be more usefully spent boosting services for those who have identified illness. In addition, they argue that there is no evidence that early intervention leads to better symptom outcomes in the long run [13].

Supporters of early intervention for psychosis argue that specialised services for first episode psychosis patients are needed to deliver the intensive biopsychosocial care that is required. The first and very well known of these in Melbourne was named the Early Psychosis Prevention and Intervention Centre (EPPIC). Such services have been shown to be superior to generic services at 12 months, 2 years and up to 5 years after entry to the service [14]. There is debate as to whether or not these improvements are maintained after the person leaves the service. However if specialist treatment can be maintained, even at a lower level of intensity, there is evidence that these good outcomes can not only be maintained but can continue to improve over 5 years [15]. Critics of specialist early psychosis services argue that specialist service treatment plans are no different from those that would be considered best practice by generic multidisciplinary psychiatry teams. This is good where it is true. But many generic teams in public mental health services are not adequately resourced for this sort of care and the crisis-driven nature of these services means that clinicians are required to keep people in case management for shorter periods than would be required to ensure the sort of intensive biopsychosocial care they need.

Those who favour early intervention point out that much of the deterioration seen in patients with schizophrenia and other psychotic disorders is not due to some inevitable biological process but due to psychosocial factors that operate in the years following first onset of illness. These psychosocial factors include disruption of education and preparation for a job or career, family stress caused by the illness, breakdown of friendships, the effects of stigma, the effects of substance use often used to relieve symptoms and the constant fear of relapse [16, 17]. These factors may well be preventable or at least ameliorated with early attention and support. Also, as mentioned above, families are usually in great distress during this early period and they desperately need education about illness and support in managing crisis which is often a major issue. When these factors are considered, whether or not the outcome in terms of symptoms a year or two later is no different for those who receive intensive care than for those who do not is somewhat academic. The longer a person remains severely ill in the community without treatment, the greater the likelihood that he or she will damage whatever supportive relationships they have and drop out of school or work. There is evidence that a lengthy DUP is at least associated with poorer outcome in terms of symptoms and functioning up to 10 years after the young person has received early intensive care [18].

These are all complex arguments to evaluate and further research will undoubtedly clarify matters over the coming years. What is clear to many of us who have worked in traditionally designed services is that the shorter the duration of established illness before treatment, the better. Indeed in our service, we often talk about ‘earlier intervention’. While figures will vary from service to service, a mean DUP of 24 months has been described even in a modern and well-resourced Melbourne service [19]. It is difficult to imagine the community accepting that we should wait until the existence of breast cancer or cardiac disease is definitively established before any interventions are attempted.