Persistent Depressive Disorder in Children and Adolescents

PDD is characterized by a year-long period (at minimum) of depressed or irritable mood during which at least two of the following symptoms are also present:

• Poor appetite or overeating
• Insomnia (not able to fall or stay asleep) or hypersomnia (sleeping too much) nearly every day.
• Fatigue or very low energy nearly every day.
• Low self esteem.
• Diminished ability to concentrate or trouble making decisions that was not previously present.
• Feelings of hopelessness.

During the year-long (at minimum) period, no more than two months may have been spent symptom-free. In addition, these symptoms must cause impairment in function – with one’s family, friends, or at school – and, as mentioned above, they must represent a change in functioning. It is possible that a child or adolescent would meet criteria for major depressive disorder, which has a duration criteria of two weeks, but later meet criteria for PDD if his/her symptoms persist for at least a year. In this case, the youth would be diagnosed with MDD and PDD – this is sometimes called “double depression.” Some youth may have trouble concentrating due to other factors, if symptoms of inattention or poor concentration existed prior to the depressed mood, caution must be taken in attributing them to the depressive episode. Finally, depressive symptoms may also occur within the context of a bipolar spectrum disorder, if a youth experiences a long period of depressed mood after first experiencing a period during which his/her mood was abnormally elevated and s/he had high energy or if s/he experiences days of elevated mood during the depression, it is possible that s/he is experiencing other specified bipolar disorder or cyclothymic disorder.

Because PDD represents a relatively chronic mood state, some youth (and their parents) may believe that they have “always” been this way and perceive their problems as personality or temperament – this may reduce the likelihood of treatment seeking. Additionally, because the symptoms are primarily internal others, may be unaware when a child or adolescent is depressed; changes in functioning and activity, along with chronic irritability are important signs to pay attention to. Comorbid disorders are common among people with PDD, including anxiety and (mostly in older youth) substance use. Youth with PDD are also at increased risk for developing a personality disorder as they age.

    There is no evidence currently for clear differences in the risk factors for PDD as compared to MDD; among youth, family history of depression or other mental illness is a significant factor, increasing risk by two-to-four times. Early onset mood disorders tend to have a stronger genetic component than mood disorders that onset late in adolescence. Additionally, temperament and personality factors are related to risk for depression, youth who exhibit high negative affect (neuroticism) and/or perfectionistic tendencies may be at higher risk. Life events can also contribute to an individual’s risk for depression; both traumatic, one-time events and chronic stressful living conditions increase vulnerability. Research using functional neuroimaging suggests that youth with MDD (we are unaware of neuroimaging research on youth with PDD specifically) show abnormal activity in the default mode network during resting state, which may be related to rumination. Additionally, youth with depression often exhibit hyperactivity of the amygdala and abnormal connectivity between the anterior cingulate and the amygdala during negative face emotion processing tasks. Finally, youth who experience chronic medical problems are more likely to develop depression than their peers.

The evidence-based treatment guidelines for depression from the American Academy of Child and Adolescent Psychiatry and the Society for Clinical Child and Adolescent Psychology suggest that psychotherapy, including the family if possible, is the best approach with which to start. For youth who are severely depressed and/or do not respond to a course of evidence-based psychotherapy, antidepressant therapy may be initiated. However, there is research suggesting that for some youth there are significant side effects associated with SSRI antidepressant medication (e.g., suicidal ideation) and that the benefits are often minimal, so antidepressant therapy must be approached with caution and under the guidance of a child psychiatrist.

First Line Treatments

• Cognitive-behavioral therapy consists of challenging negative cognitions and increasing activity in order to counteract the destructive through patterns and withdrawal that are common among people with depression.

• Interpersonal therapy is based on the idea that relationships with other people can cause or prevent symptoms of depression. Treatment consists of identifying problem relationships, improving communication skills, using new skills to improve significant relationships.

Second Line Treatments

In cases of nonresponse to first-line treatment, alternative treatments with reasonable evidence of efficacy include:

• SSRI antidepressant medications, which are thought to help by improving the amount of serotonin in the brain. The only medication with FDA approval for treating adolescent depression is fluoxetine. Other SSRIs are also used, but in trials, fluoxetine show a stronger effect, relative to placebo, possibly due to its longer half life.

Additional Treatments to Consider

Preliminary evidence suggests that the following strategies, although not a substitute for the empirically supported treatments described above, might be considered.

• Dialectical behavior therapy
• Mindfulness-based cognitive therapy
• Exercise
• Supportive psychotherapy
• Other classes of antidepressant medications such as venlafaxine, mirtazapine, and bupropion have also been tested, but do not consistently show efficacy in RCTs.