From Citizendium, the Citizens' Compendium
- Psychology : The study of systemic properties of the brain and their relation to behaviour.
- Mental illness : A disease of the brain and mind.
- Psychosis : A brain disorder characterized by severely distorted sensory perception.
- Schizophrenia : A mental disorder characterized by impaired perception of the individual's environment.
- Mood disorder : Those disorders that have a disturbance in mood as their predominant feature.
- Bipolar disorder : A mental illness of the subtype mood disorders which is also known as manic-depressive illness, characterised by the occurrence of manic or hypomanic states alternating with bouts of depression.
- Legal insanity : Add brief definition or description
- Neurosis : A term no longer used by scientists any more, it used to describe a set of psychological symptoms such as mental illness or emotional disorders marked by insecurity, anxiety, mild depression, but without serious psychotic symptoms such as hallucinations or delusions.
- Obsessive compulsive disorder : An anxiety disorder characterized by recurrent, persistent obsessions or compulsions. Obsessions are the intrusive ideas, thoughts, or images that are experienced as senseless or repugnant. Compulsions are repetitive and seemingly purposeful behavior which the individual generally recognizes as senseless and from which the individual does not derive pleasure although it may provide a release from tension.