A mood disorder is considered a mental health class that health professionals use to broadly describe all types of depression and bipolar disorders. Anyone from children, teens, and adults can have mood disorders. However, children and teens generally do not always have the same symptoms as adults and can be harder to diagnose mood disorders in children because they are not always able to express how they are feeling. The most common types of mood disorders are: • Major depression Showing less interest in usual activities, feeling upset or hopeless, and other symptoms for at least 2 weeks may indicate depression • Dysthymia Chronic, low-grade, depressed, or very irritable moods that can last for up to 2 years • Bipolar disorder Show periods of depression that alternate with periods of mania or elevated moods • Mood disorder related to another condition Many medical illnesses including cancer, infections, chronic illnesses, and injuries can trigger symptoms of depression • Substance-induced mood disorder Symptoms of depression are usually due to the effects of medicine, drug abuse, alcoholism, exposure to toxins or other forms of treatment