It is possible that there is a decreased prevalence of ODD in boys or an increased prevalence of ODD in girls in non-Western cultures, but it is also possible that the disorder is either over- or under-diagnosed in boys or girls, respectively, in Western cultures. Other factors can influence the prevalence of the disorder. Youths living in families of low socioeconomic status have a higher prevalence. Another factor is based on the criteria used to diagnose an individual. When the disorder was first included in the DSM-III, the prevalence was 25% higher than when the DSM-IV revised the criteria of diagnosis. The DSM-V made more changes to the criteria, grouping certain characteristics together in order to demonstrate that ODD display both emotional and behavioral symptomatology. In addition, criteria were added to help guide clinicians in diagnosis because of the difficulty found in identifying whether the behaviors or symptoms are directly related to the disorder or simply a phase in a childs life. Consequently, future studies may obtain results indicating a decline in prevalence between the DSM-IV and the DSM-V.

Signs and symptoms
The fourth revision of the Diagnostic and Statistical Manual (DSM-IV-TR) (now replaced by DSM-5) states that a person must exhibit four out of the eight signs and symptoms to meet the diagnostic threshold for ODD.
They may include QT prolongation, Q waves, cardiac dysrhythmias, and ST elevation that mimics a heart attack.Also one of the characteristic ECG changes that could be found in patients with subarachnoid hemorrhage, is the J waves or Osborn waves, which are positive deflections that occur at the junction between QRS complexes and ST segments, where the S point, also known as the J point, has a myocardial infarction-like elevation. J waves or Osborn waves, which represent an early repolarization and delayed depolarization of the heart ventricles, are thought to be caused by the high catecholamines surge released in patients with subarachnoid hemorrhage or brain damage, the issue that might lead to ventricular fibrillation and cardiac arrest in unmanaged patients. Classification
There are several grading scales available for SAH. The Glasgow Coma Scale (GCS) is ubiquitously used for assessing consciousness. Its three specialized scores are used to evaluate SAH; in each, a higher number is associated with a worse outcome. These scales have been derived by retrospectively matching characteristics of people with their outcomes. The first widely used scale for neurological condition following SAH was published by Botterell and Cannell in 1956 and referred to as the Botterell Grading Scale. This was modified by Hunt and Hess in 1968:
The Fisher Grade classifies the appearance of subarachnoid hemorrhage on CT scan.