The condition you are describing sounds like "Major Depressive Disorder with Mood-Congruent Psychotic Features" or "Major Depressive Disorder with Psychotic Features" (also known as psychotic depression). In this type of depression, individuals experience severe depressive episodes similar to those seen in bipolar disorder, but they do not have manic or hypomanic episodes.
In psychotic depression, the individual may have delusions (false beliefs) or hallucinations (perceiving things that are not real) that are consistent with the depressive theme. For example, they might have delusions of guilt, poverty, or worthlessness. These psychotic features can occur during severe depressive episodes and differentiate psychotic depression from other types of depression.
People with psychotic depression typically have periods of "normal" mood or fewer severe symptoms between depressive episodes, but they do not experience the distinct periods of elevated or hypomanic mood that are characteristic of bipolar disorder. In bipolar disorder, individuals experience alternating episodes of depression and mania/hypomania.
It's essential to note that diagnosing mental health conditions accurately requires a comprehensive evaluation by a qualified mental health professional. If you or someone you know is experiencing mood swings, depression, or any mental health concerns, it's crucial to seek professional help for proper assessment and treatment. Effective treatments, including psychotherapy and medications, are available to help manage and improve symptoms of depressive disorders.