If someone denies they’re mentally ill even after they’re shown clinical evidence of it, they are typically said to be “in denial.” However, acute mental illnesses like schizophrenia and bipolar disorder often prevent that person from perceiving reality objectively. In other words, a severely mentally ill individual may not be consciously choosing to deny their problem.
For people with anosognosia, the inability to have insight into their own psychological issues feels convincing and real to them. Unfortunately, this creates conflict with family members and friends who know their loved one needs help.
Anosognosia also prevents mentally ill people from seeking treatment, since they truly believe nothing is wrong with them. They may even accuse others of being overly critical of their behavior or trying to get rid of them. These effects in those with paranoid delusions or mania could lead to reckless or dangerous behavior.