The 11 psychiatric diagnoses that make up the Anxiety Disorders category of the current psychiatric nomenclature center on the manifestation of worry, concern about future threats, ruminations about performance and social acceptance, and avoidance behaviors; paradoxically, as these concerns are emotionally and cognitively experienced and acted on, the level of anxiety rises rather than falls. Anxiety symptoms often begin suddenly within the context of a specific event or challenging situation, yet may persist and manifest in an emerging chronic condition. Anxiety often co-occurs with depression and is linked to a variety of other conditions including substance abuse, interpersonal difficulties, and reduced performance in academic and professional settings.