Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infec- tions (PANDAS) has been identified as another post-infectious autoimmune disorder characterized by the sudden onset of obsessions, compulsions, and/ or tics accompanied by a variety of acute neuropsychiatric symptoms in the absence of chorea, carditis, or ar- thritis, after Group A streptococcal infection. Although there is a body of evidence that supports the existence of PANDAS, it remains a controversial diagnosis. Given this ongo- ing controversy, the description of PANDAS has been modified to eliminate etiological factors and to designate an expanded clinical entity: pediatric acute-onset neuropsychiat- ric syndrome (PANS) or idiopathic childhood acute neuropsychiatric symptoms (CANS), which deserves further study.
A number of other medical disorders are known to include obsessive-compulsive and re- lated symptoms as a manifestation. Examples include disorders leading to striatal dam- age, such as cerebral infarction.
The development and course of obsessive-compulsive and related disorder due to another medical condition generally follows the course of the underlying illness.
Laboratory assessments and/ or medical examinations are necessary to confirm the diag- nosis of another medical condition.
Delirium. A separate diagnosis of obsessive-compulsive and related disorder due to an- other medical condition is not given if the disturbance occurs exclusively during the course of a delirium. However, a diagnosis of obsessive—compulsive and related disorder due to another medical condition may be given in addition to a diagnosis of major neuro- cognitive disorder (dementia) if the etiology of the obsessive-compulsive symptoms is judged to be a physiological consequence of the pathological process causing the dementia and if obsessive-compulsive symptoms are a prominent part of the clinical presentation.
Mixed presentation of symptoms (e.g., mood and obsessive-compulsive and related disorder symptoms). If the presentation includes a mix of different types of symptoms, the specific mental disorder due to another medical condition depends on which symp- toms predominate in the clinical picture.
Substance/medication-induced obsessive-compulsive and related disorders. If there is evidence of recent or prolonged substance use (including medications with psychoac— tive effects), withdrawal from a substance, or exposure to a toxin, a substance/ medication— induced obsessive-compulsive and related disorder should be considered. When a sub- stance/medication-induced obsessive—compulsive and related disorder is being diag- nosed in relation to drugs of abuse, it may be useful to obtain a urine or blood drug screen or other appropriate laboratory evaluation. Symptoms that occur during or shortly after (i.e., within 4 weeks of) substance intoxication or withdrawal or after medication use may be especially indicative of a substance/medication—induced obsessive-compulsive and re— lated disorder, depending on the type, duration, or amount of the substance used.
Obsessive-compulsive and related disorders (primary). Obsessive-compulsive and re- lated disorder due to another medical condition should be distinguished from a primary obsessive-compulsive and related disorder. In primary mental disorders, no specific and direct causative physiological mechanisms associated with a medical condition can be demonstrated. Late age at onset or atypical symptoms suggest the need for a thorough as- sessment to rule out the diagnosis of obsessive-compulsive and related disorder due to an- other medical condition.
Illness anxiety disorder. Illness anxiety disorder is characterized by a preoccupation with having or acquiring a serious illness. In the case of illness anxiety disorder, individuals may or may not have diagnosed medical conditions.
Associated feature of another mental disorder. Obsessive-compulsive and related symp- toms may be an associated feature of another mental disorder (e.g., schizophrenia, an- orexia nervosa).