Psychotic major depression (PMD) is a type of depression that can include symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s and treatments that are different from those of non-psychotic major depressive disorder (NPMD). PMD is estimated to affect about 0.4% of the population (or one in every 250 people).

PMD is sometimes "mistaken" for NPMD, schizoaffective disorder

Schizoaffective disorder

Schizoaffective disorder is a psychiatric diagnosis that describes a mental disorder characterized by recurring episodes of elevated or depressed mood, or of simultaneously elevated and depressed mood, that alternate with, or occur together with, distortions in perception.Schizoaffective disorder...

, schizophrenia

Schizophrenia

Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...

 or other psychotic disorders. Bipolar

Bipolar disorder

Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...

 patients may experience PMD during depressed states.