Anxiety disorders are common in youth with a prevalence rate of 10% to 20%. It is associated with difficulties in academic achievement, social and peer relations and future emotional health. It is a risk factor for comorbidity and comorbidity is also very common.

Anxiety consists of a behavioural (1), physiological (2) and cognitive component (3). Anxiety

Multisystemic therapy refers to a treatment for adolescents with severe antisocial behaviour and includes their families. It is appropriate and cost-effective for youth referred to by the juvenile justice system with serious and chronic patterns of offending and at high-risk of out-of-home placement due to the relative intensity of the treatment. Teenagers with conduct disturbances and substance abuse

Trauma-focused cognitive behavioural therapy (TF-CBT) addressed problems specifically associated with traumatic events that children experience or witness (e.g. PTSD). TF-CBT targets PTSD symptoms and outcomes associated with trauma. A PTSD diagnosis is not required.

PTSD includes negative cognitions about oneself, others or the world and negative affective states. There may be dysregulation in affective, behavioural, cognitive

Difficulties in social communication in ASD may result in disruptive behaviours (e.g. aggression). This is a significant source of stress to families.

Researchers have attempted to identify pivotal responses. The idea is that when certain core areas are targeted, widespread changes in numerous other untargeted behaviours would occur, leading to fluid and integrated behavioural gains.

Some structured, manual-guided treatments may show reduced effects when they are implemented in more clinically representative contexts and compared to usual practice in those contexts. This may be because treatments tend to be developed away from the clinical practice. There are several potential mismatches between evidence-based practice and real-world clinical care:

1. Clinicians in practice settings typically