<human>:  Can you tell me about the different types of depression and their signs and symptoms?
<bot>: There are several types of depression that all vary in severity and symptoms. Major depressive disorder is the most common type, and it can cause feelings of sadness, hopelessness, worthlessness, and low self-esteem. Other more severe types of depression include persistent depressive disorder, bipolar disorder, and postpartum depression. Symptoms of these types of depression can include fatigue, changes in sleep and eating patterns, restlessness, concentration problems, and thoughts of suicide or death. Additionally, psychotic depression is a type of depression that can involve psychotic symptoms such as delusions or hallucinations.