The negative effects of comorbidity include&colon; chronicity, recovery and relapse rates, and higher suicide risk. In the case of post-puberty chronicity residual symptoms and their severity increases. The diagnosis depends on two factors, namely chronicity and reversibility. This information helps explain the severity and chronicity of addiction in certain individuals. Once diagnosed, it is characterized by its chronicity, anatomic location or histologic subtype. Recurrence or chronicity is more likely if symptoms have not fully resolved with treatment. It is characterised by sudden-onset and chronicity as well as having a propensity for relapse. The clinical presentation of hydrocephalus varies with chronicity.