But chronic vomiting (vomiting that
persists for two or three days in a row) can happen for a host of reasons — inflammatory bowel disease, viral or bacterial infections,
problems with the pancreas or digestive
systems, neoplasia, kidney disease, or liver disease — and needs to be diagnosed and treated as soon as possible.
Anxiety disorders are among the most common mental disorders during childhood and adolescence,
with a prevalence of 3 — 5 % in school - age children (6 — 12 years) and 10 — 19 % in adolescents (13 — 18 years); 1, 2 and the prevalence of anxiety disorders in this population tends to increase over time.3 Anxiety is the most common psychological symptom reported by children and adolescents; however, presentation varies
with age as younger patients often report undifferentiated anxiety symptoms, for example, muscle tension, headache, stomachache or angry outbursts.4 According to the standard diagnostic
systems, there are various types of anxiety disorders, for example, generalised anxiety disorder (GAD), social phobias (SOP), social anxiety disorder (SAD), panic disorder (PD), overanxious disorder, separation anxiety, post-traumatic stress disorder (PTSD), obsessive - compulsive disorder (OCD).5 Anxiety disorders in children and adolescents often occur
with a number of comorbidities, such as autism spectrum disorders, 6 depressive disorders, 7 conduct disorder, 8 substance abuse9 or suicide - related behaviour.10 Youths
with anxiety disorders experience serious impairment in social functioning (eg, poor school achievement; relational
problems with family members and peers).11, 12 Childhood and adolescent anxiety disorders can
persist despite treatment, 1 and they are associated
with later adult psychopathology.13, 14