For much of its history, separation anxiety has been a relatively neglected domain in psychiatry. Lifting the age restriction (<18 years in DSM-IV) on the diagnosis of SAD reflects the increasing evidence that disorder onset is not limited to childhood or adolescence, but often first manifests during adulthood.

Epidemiological data revealed a high lifetime prevalence of childhood-onset SAD (CSAD) of about 4%, but a higher lifetime prevalence of 6.1% for adult-onset SAD (ASAD), with 36.1% of childhood-onset cases persisting into adulthood and as many as 77.5% of adult cases reporting first onset after the age of 18. Childhood prevalence rates are higher in girls than boys, although sex differences are less pronounced in adulthood. However, men are more likely to report disorder onset during adulthood. SAD appears to be highly comorbid with and antecedent to other mental disorders, including anxiety disorders, depression and bipolar disorder, stress-related disorders, and personality disorders. Including SAD in the group of anxiety disorders and thereby lifting the age limit in the DSM-5 has renewed research efforts into its epidemiology and etiology. Surely, separation anxiety has been shown to complicate the course and severity of these comorbid disorders. This may in part pertain to the elucidation of neurobiological mechanisms, which on the one hand, may constitute stable risk factors of SAD across age groups, and, on the other hand, act as neutral, adaptive or maladaptive markers depending on different time windows of age.

We approached this book with the clinician in mind. Throughout, we have emphasized the clinical implications of current research while also seeking to provide critical reviews to stimulate further research developments.

This book reflects the crossroads at which we currently stand: the very provisional status of our theoretical map, our frustration with achieving good outcomes clinically with people afflicted by separation anxiety disorder into adulthood, and some basic unresolved questions.

Is a reliable and valid taxonomy of anxiety disorders possible that considers the role and impact of separation anxiety? Can contemporary heuristic approaches to axis I mental health problems, as many still call them, be adapted for separation anxiety as a clinically meaningful entity (as has happened with psychotherapies), or do we need new approaches?

How can psychiatrists and psychologists reconcile their biopsychosocial formulations with the ramifications of separation anxiety disorder as a diagnosis that, originating from the realm of attachment theory, is now considered a condition with equal relevance as other mental disorders? The ramifications and complexity of attachment relationships and their implications for emotional development have been difficult to assimilate into the more phenomenologically-driven realm of general psychiatric nosology. However, attachment remains crucial to mental health, severity of psychopathology, and what goes into our understanding of which patients have more promising vs. less promising prognoses.

How much of the clinical and theoretical consensus that has crept into classification systems and contemporary practice will stand the test of systematic research in this area over the next few decades? Incorporating attachment and development into the realm of psychiatric nosology carries some hope with it of greater understanding. Sadly, because of psychoanalysis’ long history of eschewing systematic research and maintaining a literature separate from mainstream mental health literature [1, 2], theoretical constructs such as classical psychoanalytically-derived object relations theory did not stimulate systematic empirical research. This represents a lost opportunity. The problem is not that theories are necessarily wrong but rather that they remain untested. Although elements of the separation anxiety syndrome are captured by parts some of these theories [3, 4], they do not incorporate essential developments elucidating psychopathological trajectories that pertain to separation anxiety as is currently understood.

For these reasons, it was decided to organize the volume around key topics rather than to allow contemporary models to impose a structure that is justified by the evidence available, which in many domains is inadequate to make definitive statements. The intention is to provide a systematic account of empirical knowledge that is as little concentrated as possible by unsubstantiated assumptions of traditional models and theories while at the same time recognizing their importance. The focus of this book is on empirical knowledge and the implications it has for both theory and practice in working with patients who clinically suffer from separation anxiety.