The depressive disorders are characterized primarily by mood disturbance (sad, empty, or irritable mood). Individuals with depressive disorders often experience significant somatic changes, such as disruptions in sleep (insomnia or hypersomnia), eating (overeating or loss of appetite), or energy level. Changes in cognition, such as difficulty concentrating, indecisiveness, and morbid ideation (such as thoughts of death) are also common.
Individuals with major depressive disorder experience pervasive sadness or anhedonia (loss of interest) along with significant changes in somatic and/or cognitive functioning. To be diagnosed, these problems must be present nearly every day for at least two weeks. Individuals with persistent depressive disorder (dysthymia) experience similar symptoms, including sad mood and problems with somatic and/or cognitive functioning that occur most days for at least two years. Disruptive mood dysregulation disorder is diagnosed in children under 12 years old who experience persistent irritability and extreme behavioral dyscontrol.
These disorders can go undetected in youth because they are internalizing disorders, whereas many other childhood disorders are associated with externalizing symptoms, which are more likely to draw attention from parents and teachers. The exception is disruptive mood dysregulation disorder, which is characterized by temper outbursts; this may be related to an inability to effectively express internal distress and is likely to result in misdiagnosis as oppositional defiant disorder or bipolar disorder.
Major depressive disorder (MDD) is an episodic illness; though some people experience only one episode, the majority will experience recurrent episodes. This may be particularly true for children; youth who become depressed often continue to struggle with depressed mood as adults. In contrast, both disruptive mood dysregulation disorder (DMDD) and persistent depressive disorder (PDD) are more chronic illnesses. Youth who meet criteria for DMDD or PDD must experience symptoms for at least one year with no more than two months (cumulative) symptom-free. Though DMDD and PDD can be longer lasting than an episode of major depression, the symptoms are usually not as severe. DMDD is characterized by persistent irritability and temper tantrums. PDD is more similar to major depression symptomatically – youth with this illness experience sad / depressed mood along with physical and cognitive symptoms.
All of the depressive disorders represent a change in functioning; though PDD and DMDD have a more chronic presentation, all three illnesses are episodic (although PDD and DMDD are defined by prolonged periods of low/irritable mood, these are also episodic; there must be a change of functioning at the onset of illness and the expectation is that symptoms will eventually remit) and, in most cases, there will be fluctuations in the severity of symptoms, due to time or treatment Many people with depressive disorders also experience significant somatic symptoms, and youth may complain of headaches or stomach aches, along with exhibiting low energy. Additionally, many youth with a depressive disorder diagnosis experience hopelessness and suicidal thoughts. The risk of suicide is a significant concern in this population and should be monitored closely.