Contrary to the dimensional approach, categorical approaches focus on the presence or absence of a particular condition or set of symptoms. The most commonly used diagnostic manuals, such as DSM and ICD use a categorical approach in their classification of mental disorders. Categorical approaches have been criticized somewhat, with critics stating that they do not adequately address several critical elements of disorders in their diagnoses, such as individual differences in severity, the variability of contributing factors, variances in appearance of various disorders, and comorbidity with other disorders.