Depressive disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM–5) include diagnoses of different disorders, for example, major depressive disorder (MDD), disruptive mood dysregulation, persistent depressive disorder, and depression not otherwise specified. This article reviews major depressive disorder (MDD).
MDD is the first cause of disability among adolescents aged 10 to 19 years (WHO 2014). Suicide is the third cause of death in this age group, and adolescent depression is a major risk factor for suicide. Depressed adolescents experienced significantly more stressors during the year before onset when compared with a comparable 12-month period in normal controls.
The etiology of depression is multifactorial and complex resulting from interactions between biological vulnerabilities and environmental factors.
Genes and Heritability
A meta-analysis found that heritability is a main risk factor for mental health concerns, including depression, between ages 13 and 35. In twin studies, heritability was found to be around 60% to 70%.
Offspring of depressed parents have an increased risk of 2 to 4 times compared with offspring of healthy parents. Genes-environmental interaction contributes to this risk, specifically by increasing by increasing susceptibility to environmental stress. Also, different studies reported that the serotonin transporter gene variant (5-HTTLPR) might increase the risk of depression in the presence of adverse life events or early maltreatment.
Puberty and Brain Development
Psychosocial Risk Factors
Stressful life events often precede the onset and recurrence of depressive symptoms and episodes in adolescents, especially with girls. However, most children and adolescents who experience such events do not develop depression. Examples of life stressors include events involving loss, maltreatment, romantic break-up, being bullied by peers, and parent-child conflicts.
Cognitive Risk Factors
Depressed adolescents have an attentional bias and a memory bias. They recall more negative and fewer positive words than a non-depressed adolescent. There is a bidirectional relationship between children's low perceived competence and depression. Children’s underestimation of their competence predicts depressive symptoms and vice versa. Previous depression also predicts underestimation of competence. Rumination, dwelling excessively, does also predict the onset and continuation of depression.
The pediatric depression annual incidence rate is 1% to 2% at age 13 and from 3% to 7% at age 15. The ratio is equal between male and female during childhood (1:1) and 1:2 during adolescence. After puberty, the risk of depression increases by a factor of 2 to 4, particularly in females. Different studies reported that lower or middle-income countries have higher rates of depression in adolescents compared to higher income countries (10% to 13% in boys and 12% to 18% for girls).
DSM–5 criteria for diagnosing depression in the pediatric population:
The illness causes clinically remarkable distress or impairment in social, occupational, or other important areas of functioning.
The episode is not due to the physiological effects of a substance or another medical condition
The occurrence of the major depressive episode cannot be explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, or other specified and unspecified schizophrenia spectrum and other psychotic disorders
Had no manic or hypomanic episodes
The USPSTF (US Preventive Services Task Force) recommends screening for a major depressive disorder (MDD) in adolescents aged 12 to 18 years. Some screening questionaries are available to screen for depression in primary settings. Examples are:
There is no specific blood test or imaging that can be done to diagnose depression. However, the evaluation of depression needs to include some investigations to rule out some of the differential diagnosis. Examples are:
Other investigations should be ordered whenever other medical illnesses are suspected, for example, urine toxicology screen, blood alcohol level, HIV test, dexamethasone suppression test, and ACTH stimulation test.
Treatment should aim for recovery, achieving full remission of symptoms, and returning to the premorbid level of functioning. Biopsychosocial treatment plans for children and adolescent is similar to adults' plans. However, in children and adolescents, clinicians often start with psychosocial interventions.
Psychosocial Interventions Involving the Child and Parents
Psychosocial interventions are the first-line treatment in case of mild-to-moderate depression.
Different studies had shown that antidepressants efficacy is different between adults and children. The placebo effect is stronger among children and adolescents compared to adults, especially with mild-moderate depression.
It is important to discuss the effects and side-effects with the patient and parents. Typically, for the first month after prescribing an antidepressant follow-up should be weekly. This allows for close monitoring of side effects as well as supportive management.
Antidepressants that are most commonly used in this age group are fluoxetine, sertraline, citalopram, and escitalopram. Fluoxetine and escitalopram are approved by the FDA for adolescent depression. Venlafaxine, a serotonin-norepinephrine repute inhibitor (SNRI), is a second-line drug due to its side effects.
One of the major side effects of antidepressants is an increase in suicidal thoughts, but not suicidal attempts. Thus, monitoring suicidal risk is required. Other side effects include gastrointestinal problems, agitation, nightmares and sleep disturbance, weight gain, and sexual dysfunction.
Management of Comorbid Disorders
Clinicians should monitor comorbid disorders such as sleep disorders, anxiety disorders, and other underlying medical causes of depression.
To diagnose a bipolar affective disorder, clinicians need to document one manic or hypomanic episode. The challenge with the pediatric population is that bipolar disorders often start with an episode of depression in childhood or adolescence.
The onset of symptoms in adjustment disorder occurs following a significant life event.
Substance Use Disorders
Either withdrawal from substances, for example, amphetamines or cocaine, or intoxication (alcohol) could present with a clinical picture similar to depression. Depression could be diagnosed as a concurrent disorder if depressive symptoms persist or precede the onset of substance use.
Different medical conditions could present with depression, for example, multiple sclerosis, stroke, or hypothyroidism.
Attention-Deficit Hyperactivity Disorder
Attention-deficit hyperactivity disorder (ADHD) could present with irritable mood, poor concentration, and these symptoms are similar in pediatric depression symptoms.
The most important factor in predicting the severity and improvement percentage of depression is the duration of untreated depression. Active treatment decreases the depressive episode duration. Remission rate depends on different factors like disorder severity, with rates among people with severe disorders being 20% to 30% lower than mild-to-moderate depression. Around, 60 % to 90% of mild-to-moderate depressive episodes in adolescents remit within a year. However, recurrence within 5 years occurs in around 50 % to 70%. Patients with major depression from specialist psychiatry settings have had long-term recurrence rates of between 50% and 64%. Relapse rate is higher when the remission from depression is partial (67.6%) compared to when it is complete remission (15.18%). Children and adolescents who develop a recurrent or chronic disorder extending into adulthood are more likely to suffer considerable disability and impairment.
Major depressive disorder in the pediatric population is a treatable condition. However, it is mostly underdiagnosed and under-treated. The goal of treatment should be to minimize the impact of depression on the child's functioning at home, school and on the social/peer relationships while aiming for a full recovery. This would be better obtained via outpatient treatment with an interprofessional team consisting of a mental health nurse, a psychiatrist, a pediatrician, a psychotherapist, and a case manager. Admission to the inpatient unit should be considered when the depression is severe, or the child's safety cannot be guaranteed. Pediatricians and mental health professionals should always promote and advocate for this population's mental health, increase awareness and aim for decreasing the stigma.