Nine per cent of British children will meet DSM-IV criteria for childhood disorder of a severity that impairs functioning and warrants treatment [14]. Rates of disorder increase with age and those first evident in childhood, such as anxiety, depression and conduct disorder, peak in adolescence – with increases in the rate of depression being most common in girls and of conduct disorder in boys. Other disorders show their peak onset in adolescence including psychosis, bipolar, eating and emerging personality disorders. While estimates of comorbidity vary across studies, depending in part upon diagnostic criteria, conservative estimates suggest that at least a quarter of children will experience comorbid disorders, these being particularly evident between anxiety and depression, between attention deficit and hyperactivity disorder (ADHD) and behaviour disorders and between depression and some behaviour disorders [14, 15].

Specialist mental health care for children, young people and their families in the United Kingdom is provided within CAMHS, a public health service free at the point of delivery. Within England and Wales, the service is divided into four increasingly specialized tiers, with Tiers 3 and 4 (the focus of this chapter), providing multi-disciplinary team services for children and young people with the most serious problems. In practice, children and their families may be involved in different services across the tiers, concurrently or historically, as well as with other social and health agencies that come under the umbrella of children’s services [7]. Consequently, multi-agency working, within and across health, education and social care sectors tends to be the rule rather than the exception. While the organization of CAMHS services may differ in Scotland and Northern Ireland, both countries offer multi-disciplinary CAMHS for children with the most serious mental health needs, and the transition from CAMHS to AMHS raises concerns similar to those elsewhere in the United Kingdom [16, 17].

The types of therapy provided in specialist services reflect their multi-disciplinary composition, and can include psychological, psychotherapeutic and systemic therapies as well as pharmacotherapy. The model of service delivery is developmental – reflecting children’s biological, psychological, and social needs as well as the onset and course of differing disorders over childhood and adolescence. Families and careers are an integral part of therapeutic interventions, though the extent of their involvement and the role they play change as the child matures. With younger children, parents may act as ‘co-therapists’, while by the time their child reaches the legal age to give consent to treatment (16 years), parents will often be seen separately as a supportive adjunct to individualized treatment of their child. Across the age range, whatever the form of treatment employed, viewing the child within the context of the family and utilizing family resources to aid in the recovery process are integral to service provision.

Longitudinal epidemiological studies show that serious child and adolescent emotional and behavioural problems, and child mental health service use, predict adult psychiatric disorder [18, 19]. For example child and adolescent conduct/opposition problems predict anxiety and depression, antisocial personality and psychotic disorders in young adults [18, 20]. Retrospective analyses of adults with psychiatric disorder, drawn from a birth cohort study, indicate that about 73% had received a psychiatric diagnosis before 18 years of age, and 50% before 15 years of age. Up to 60% had a history of conduct and/or oppositional defiant disorder [21]. ADHD is now thought to persist in about 50–60% of adolescents, and recent evidence suggests a continuation into young adulthood, with prevalence rates in those previously diagnosed in childhood varying according to whether they met full diagnostic criteria (15%) or were in partial remission (65%) [22]. Vulnerability of those with emotional disorders continues into young adulthood [19]. World Health Organization figures reveal that suicide, uncommon in childhood and early adolescence, increases markedly from mid-adolescence to early adulthood. In the United Kingdom in 2003, suicide rates for those aged 15–24 years were 8 per 100,000 for males and 2.3 for girls [23]. Clearly, child and adolescent mental health problems represent a key risk factor for psychiatric problems in adulthood.

Broader-based outcome studies are also relevant. For instance, a recent longitudinal study of three successive cohorts of youth with serious emotional disturbance found a decline in rates of employment, and increases in employment instability and involvement in crime. Of those aged 21–25 in 2009, 60.5% had been arrested and 44.2% had been on probation or parole [24]. Similarly, adult outcomes for those with ADHD include educational and occupational failure, disturbed interpersonal relationships, delinquency and criminality [22].

The evidence for continuities in psychopathology and psychiatric disorder argues for the provision of, and smooth transition to, appropriate service support as adolescents transition into adulthood. Yet, both nationally and internationally, problems at the interface of child and adult mental health services are more likely to lead to discontinuities rather than continuities in care [25, 26].

CAMHS and AMHS differ markedly in a variety of ways, stemming from differences in their history, culture, models of care and service configurations. These differences can result in difficulties at the interface between services, such that Singh and colleagues found only 58% of those leaving CAMHS transferred into AMHS and less than 5% of them experienced an optimal transition [2]. Additional factors impacting on the transition process include client characteristics such as diagnostic profiles and variation in developmental and clinical needs.

Eligibility for services Young people receiving care from CAMHS evidence a wide range of emotional and behavioural problems – problems often complicated in adolescence by the emergence of risk-taking behaviours, accommodation needs and early parenthood. Complex mental health, social and developmental needs are evident as they move into young adulthood. The main criteria for eligibility into CAMHS is essentially that the child or young person is experiencing a mental health difficulty that is impairing their own, and/or their family’s functioning in daily life. In contrast, AMHS services, with their greater emphasis on biological disorders, are likely to have eligibility criteria resting upon the presence of ‘a severe and enduring mental illness’. Singh and colleagues [2] found that those most likely to make the transition to AMHS were those who met this criterion and/or who had a history of admission to inpatient units. Many young people attending CAMHS, though in need of continuing mental health care, are unlikely to meet this diagnostic threshold. A situation further complicated in young people by the diagnostic uncertainty stemming from an overlap between normal adolescent turmoil and the nonspecific prodrome of serious mental illness.

Service entry and exit from mental health services is also determined by age criteria. Where these are inflexible, barriers between services arise. With the exception of specialized services such as early intervention services (EIS) for those experiencing the early onset of serious mental health disorders (see Chapter 15), AMHS are largely available from the age of 18 years – the age which government policy suggests as the upper limit for CAMHS [7]. Nonetheless, geographic variations results in some CAMHS services not being offered beyond the age of 16 years, unless the young person remains in full-time education [3].

Doubtless, these rigid boundaries reflect clinicians’ attempts to operate within service and resource constraints. Yet the impact upon those needing services is a marked gap in service provision. The resource implications of providing a comprehensive CAMHS service to 16 and 17 year olds are significant [11]. Yet the alternatives can include some young people being rejected – even for AMHS waiting lists until age criteria are met; or not being considered suitable for AMHS until a mental health crisis is reached, with entry into adult services then being potentially traumatic and emotionally costly to the young person and their family.

Service ethos, therapeutic models and transition protocols Treatments available to young people and their families in CAMHS, such as systemic family therapy and individual psychotherapy alongside supportive family work, are unlikely to be available in many AMHS. Those seeking a continuation of such therapies can therefore experience an abrupt end to their care. Also, the person-centred focus of AMHS with its greater emphasis on autonomy and self-determination can effectively exclude families/carers, even though they remain highly involved in the young person’s care [27].

This change in ethos can interact unhelpfully with the developmental needs of young people. In eating disorders (ED), for example CAMHS treatment models are likely to involve parents and young people combining to ‘fight the ED’ [28]. Young CAMHS leavers entering Adult Eating Disorder Services seem particularly likely to have maturational issues [29]. A sudden, poorly co-coordinated move to AMHS that emphasise individual autonomy, the acceptance of personal responsibility for tackling disorder and the exclusion of families can be ‘bewildering and dangerous for patients and their families’ [30, p. 399].

Achieving the right balance between respecting client confidentiality and utilizing family support is a difficult task. Within CAMHS negotiations as to what information can and cannot be shared with others both prior to and during therapy are common. While regular contact with carers during transition forms part of the care model of EIS services, in other AMHS services, confidentiality can be used as a ‘smokescreen’ functioning to exclude families and carers [31].

It is not surprising, therefore, that Singh and colleagues [3] conclude that differing service and therapeutic models, communication difficulties, differences in protocols relating to how care needs are assessed, and misperceptions and poor communication between child and adult services hamper smooth transition between the two. These difficulties are enhanced in services lacking clear transition policies and protocols to guide and set standards for the process. Singh and colleagues’ survey [1] indicates that only a minority of CAMHS services had developed policies and protocols governing these service transitions. In others, the protocols either did not exist or were not followed – representing a failure to implement government policy guidelines.