This chapter reviews biological factors potentially involved in depersonalization/derealization (dpdr) and depersonalization/derealization disorder (DDD). It discusses sensory association cortical areas and corticocortical dysconnectivity models in relation to perceptual alterations, the limbic system and cortico-limbic disconnection hypothesis regarding hypoemotionality, and findings on the autonomic system and hypothalamic-pituitary-adrenal (HPA) axis. The putative roles of the serotonergic and endogenous opioid systems are examined, along with brain rhythm findings related to dissociation and the neuroscience of selfhood.
Depersonalization is the third most common psychiatric symptom, yet remains poorly understood by clinicians and the public. It can accompany other mental illnesses but is also a distinct disorder recognized by major diagnostic manuals. This chapter describes the symptoms of depersonalization/derealization disorder through historical documentation and personal stories. Core symptoms include detachment from one's whole self or aspects of the self (feelings, thoughts, body, agency) and detachment from the outside world. The origins of the term "depersonalization" are discussed, and historical and current descriptions are illustrated with personal quotes and stories, supporting depersonalization/derealization as an independent syndrome rather than merely a symptom of other disorders.