Depression in Children and Adolescents

JOSEPH M. REY

PHILIP L. HAZELL

KEY POINTS

Depression is one of the most common psychological disorders in children and adolescents, and as such it needs to be diagnosed and treated not only by specialists but also in primary care settings.
Often depressive illnesses are chronic, recurrent, and incapacitating, more similar to asthma than pneumonia. This is often overlooked.
When they grow up, depressed youth are more likely to never marry, be more impaired socially and occupationally, have a poorer quality of life and greater medical and psychiatric morbidity, suffer more depressive episodes, and are more likely to commit suicide than those without depression.
Diagnosis is complex because depression is a normal human experience, can be a symptom in a variety of physical and psychological disorders, a syndrome, or an illness. Diagnosis requires careful examination of symptoms and impairment, and exclusion of conditions that mimic depression.
Although not always possible, it is helpful to know which subtype of depression is afflicting a child because of its implications for treatment and prognosis.
Medical conditions, medications, and substances of abuse can cause symptoms that are similar to depression.
Depression often co-occurs with other mental disorders. As a result it can be overlooked, particularly when comorbid with attention deficit hyperactivity disorder (ADHD) and disruptive behavior disorders because parents and teachers focus on the annoying behaviors of the child and overlook unhappiness and depressed mood.

The challenge of understanding how depression in young people develops, is diagnosed, and treated often begins with presentations like Sarah’s. This process is complex because unhappiness is a normal human experience; periods of sadness are a common response to everyday events such as changing school, teasing, the breakup of relationships, parental illness, or exam pressures. Because the word depression can mean a symptom in a variety of psychological disorders, a syndrome, or an illness, it is used here to denote an illness, clinical depression, which includes major depressive disorder (MDD) and dysthymia. Thus clinicians need to determine whether Sarah’s symptoms fulfill criteria for a psychiatric disorder (e.g., major depression), their relationship to biologic, psychologic, social, and cultural aspects of development, impact on her daily life and adjustment (e.g., on progress at school), connection with family functioning, whether treatment is required, and which treatment is most appropriate. Sarah did not seek help herself but was brought to the physician by her mother, who thought the time was right to seek assistance. This is because many children do not
understand they are unwell (e.g., may blame family, school, or friends for their feelings) or are unable to express in words their subjective experiences, or they are frightened and do not want to be evaluated by a clinician. Sarah’s need for help was defined by another person, and the clinician should therefore explore what the problem is from the mother’s perspective.

A recent World Economic Forum in Davos, Switzerland, discussed depression among other weighty topics. The forum was told that according to the World Health Organization (WHO), depressive illness was the leading cause of disability worldwide in terms of number of people afflicted, and it is forecast to become worse by the year 2020.1 The fact that a psychiatric illness was discussed at all in such a forum is in itself telling. Besides disability, the cost of treatment is also large, particularly because depression is often a lifelong problem. Also, depression increases the risk of medical illness, academic, work, social, and family problems, and it is the major cause of suicide in youth.2 As described later in this chapter, depression is one of the most common disorders afflicting not only adults but also the young, and an even greater number of children live with an adult who suffers from the condition.

Little is known about the public’s perceptions of depression in the young. However, American people seem to believe childhood depression is a more serious illness than adult depression and in need of formal, even involuntary, treatment.3 They also perceive depressed youth as potentially violent, probably as a result of the publicity surrounding the tragic Columbine High School events and similar incidents elsewhere.3 This shows not only that depression in the young is recognized as a serious illness but also that it regrettably carries considerable stigma (e.g., sufferers are perceived as weak, potentially dangerous). By contrast, evidence indicates that depression in the young is often not detected or treated. For example, 66% of depressed adolescents identified in an epidemiologic study had not used any treatment services.4 However, when they did, they almost always used more than one service (e.g., school counseling, medical, mental health). Of the adolescents who had consulted a physician, all had attended counseling services, and almost all had used mental health services. Only 3% had taken antidepressant medication. This situation might be improving because of education campaigns targeting health professionals and the community at large.

There are suggestions that depression is becoming more common with successive generations and presenting at a younger age.5 It is also likely that most people who ever suffer from depression will have experienced their first episode before 20 years of age. Childhood depression is therefore too common to be the exclusive domain of specialist services. Just as primary care physicians treat many adults with mild to moderate depressive illness, they may increasingly provide a similar service to children and adolescents; to do so will require gaining knowledge and skills in this area.

DEFINITION

Depression is an episodic or chronic disorder characterized by persistent and pervasive sadness or unhappiness, loss of enjoyment of everyday activities, irritability, boredom, and associated symptoms such as negative thinking, lack of energy, difficulty concentrating, and appetite and sleep disturbance. To have a depressive disorder, the individual’s functioning must also be impaired. Depression exists in a continuum, although manifestations may vary according to age, gender, and cultural background. The various subtypes are identified on the basis of symptom severity, pervasiveness, functional impairment, or the presence or absence of manic episodes.

HISTORICAL NOTE

Depression has existed in all recorded historical times. For example, King Saul is depicted as depressed and committing suicide in the Old Testament. Robert Burton in his book Anatomy of Melancholy (1621) described not only the symptoms of depression but also explored its psychological and social causes (such as poverty, fear, and solitude). The German psychiatrist Emil Kraepelin (1856–1926) identified “manic depression” (bipolar disorder) as a separate condition. Thus depression in adults is an illness known for a long time and for which new treatments such as psychotherapy, electroconvulsive therapy, and antidepressant drugs were gradually introduced during the 20th century. Yet this was not the case for children.

Psychoanalytic theories mostly posited that depression was the result of superego-driven introjection of aggressive impulses.6 These theories also assumed that children did not have a well-developed superego and thus could not introject aggression and experience depression. Because psychoanalysis dominated the thinking about depression in the first half of the 20th century, childhood depression was ignored until the 1960s when new currents of thought gathered momentum. For example, according to the proponents of the “masked depression” theory, children can be depressed but express this differently from adults, as conduct problems or physical complaints: “depressive equivalents.”6 Although the concept of masked depression was heavily criticized and subsequently abandoned, the debate rekindled interest on childhood depression, also because many clinicians had noted that children in their practices often showed depressive phenomena. By the 1970s researchers began to accept that childhood depression did exist, and the focus moved on to defining its characteristics.

When the third edition of the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association (DSM-III) was published in 1980, many experts already acknowledged that childhood depression shared the essential clinical features of adult depression. The issue was whether children also displayed developmentally specific symptoms, such as somatic complaints, negativism, or aggressiveness, which are not characteristic of the adult syndrome. The following edition, DSM-IV, states the core symptoms are the same for children, adolescents, and adults, but it acknowledges the pattern may vary with age, so much so that “irritable mood” in children is accepted as a diagnostic equivalent of depressed mood. The WHO’s International Classification of Diseases, 10th edition (ICD-10) recognizes a similar disorder.

The concept of dysthymic disorder or dysthymia was introduced in DSM-III to denote a less severe, less pervasive but more chronic form of depression that often starts during childhood. This diagnosis has been retained with similar characteristics in both DSM-IV and ICD-10, although questions remain about whether dysthymia is a separate condition.7

An update of the classification systems (DSM-V and ICD-11) is under way, but drastic changes are unlikely. Yet arguments about the existence of specific subtypes (e.g., melancholia), dimensional versus categorical approaches, and the overlap with anxiety disorders (suggesting the existence of one single condition) remain.8 It has been argued also that major depression can be accurately diagnosed using only three out of five psychological symptoms (depressed mood, lack of interest, worthlessness, poor concentration, and thoughts of death, a subset of the nine symptoms currently used).9 This has the advantage of being easier to remember. The search now is for objective biologic markers that may help identify the various subtypes of depression earlier and more reliably.

Media stories about a rapid rise in the prescription of antidepressant drugs, unmet expectations regarding their effectiveness, and concerns relating to their safety, particularly about suicidal behavior (see Chapters 6 and 14) have caused anxiety among clinicians, parents, and ill young people. This led some to question again the validity of youth depression, resulting in the reemergence of idiosyncratic or discredited theories, denial of its very existence (e.g., depression in the young is just medicalization of the unhappiness experienced by today’s affluent children), trivialization of the illness or stigmatization (e.g., a weakness of character),10 and a drop in diagnosis and prescription of antidepressants.11

EPIDEMIOLOGY

Prevalence estimates for current or recent MDD or dysthymia from selected community surveys of children and adolescents using DSM-IV criteria range from 0.9% to 3.4% (Table 1.1). Rates can vary depending on the population, the period considered, informant, and criteria used for diagnosis. The cumulative prevalence (accumulation of new cases in previously unaffected individuals, also known as lifetime prevalence) is much higher. For example, by the age of 16 years, 12% of girls and 7% of boys would have had a depressive disorder at some stage in their lives, according to a study conducted in North Carolina.12 Prevalence of dysthymic disorder is less well known, but studies suggest a point prevalence ranging from 0.6% to 1.7% in children and 1.6% to 8.0% in adolescents.5 A further 5% to 10% of young persons have been estimated to exhibit subsyndromal depression (or “minor depression”). Youth with minor depression show considerable impairment, an increased risk of suicide, and of developing major depression.13

TABLE 1.1 PREVALENCE (%) OF DSM-IV DEPRESSIVE DISORDERS (MAJOR DEPRESSION, DYSTHYMIA) ACCORDING TO LARGE EPIDEMIOLOGIC STUDIES OF CHILDREN AND ADOLESCENTS

Population	Children	Adolescents	Females	Males	Overall
1,420 children from North Carolina, 9–13 yr, at first assessment^12(a)	0.9	3.1	2.8	1.6	2.2
10,438 British children, 5–15 yr^19(b)	0.4	2.5	1.0	0.9	0.9
3,171 Australian children, 6–17 yr^20(c)			2.8	3.2	3.0
1,886 children, 4–17 yr, from Puerto Rico^21(d)			5.2	0.3	3.4
1,107 girls, 12–17 yr, from Sudan^22(b)			4.4
^aThree-month prevalence. ^bPoint prevalence. ^cOne-year prevalence. ^dSix-month prevalence.

Earlier epidemiologic studies using DSM-III-R criteria produced similar results. For example, Lewinsohn et al.14 reported a point prevalence for major depression among high school students in
the Unite States of 2.6% (males, 1.7%; females, 3.4%) and 0.5% for dysthymia (males, 0.5%; females, 0.6%). Lifetime prevalence was much higher: 18.5% for major depression and 3.2% for dysthymia.

The ratio of depression in males and females is similar among children but becomes about twice as common among females during adolescence15 (see Chapter 2). Clinical impressions suggest rates of depression may be especially high in particular groups such as developmentally disabled or indigenous children (e.g., Native Americans, Eskimos, and Australian Aborigines) (see Chapters 21, 22, and 23). An American survey reported that prevalence of depression among attendees of a pediatric primary care service was no greater than that found in the general population.16 However, the prevalence of depression is substantially higher among patients who suffer from chronic medical conditions (see Chapter 21).

AGE OF ONSET AND COURSE

Depression that begins prior to puberty may be different from depression that begins in adolescence or adult life, or at least more heterogeneous. Also, clinical presentation in children can be different from adolescents (see Chapter 3). Depressed adolescents are more likely to show hopelessness and helplessness, lack of energy or tiredness, hypersomnia, weight loss, substance abuse, delusions, and suicidal ideation and attempts compared with children. Conversely, children are likely to show irritability, hallucinations, comorbid separation anxiety, and ADHD more often.5 It is during adolescence that depression becomes more common in girls than boys, suggesting the neurobiologic changes underpinning gender differentiation during this period may also be linked to the causation of depression. Whereas younger children respond less predictably to pharmacologic treatments, older adolescents respond to antidepressant drugs in a manner more similar to adults,17,18 again suggesting that the neurobiologic subtract mediating depression is established or modified during adolescence. The influence of genes on the expression of depression in adolescents is similar to that in adults, whereas in children environmental factors seem to play a more important role. Although much of the depression occurring in adolescence is new-onset disorder, a significant minority of teenagers have already experienced problems in their prepubertal years; for some this is depression, and for others it is an anxiety disorder, ADHD, or conduct problems.23 Given the overlap of these conditions with depression, clinicians who are treating young people for other psychiatric disorders should, over time, be on the lookout for the emergence of depressive symptoms.

Similar to adults, MDD in youth follows a relapsing course (for definitions of recurrence, relapse, etc., see Table 4.1). An episode of depression in clinically referred groups lasts 7 to 9 months on average, but it is shorter in nonreferred community samples.13 That is, MDD is a spontaneously remitting illness, which may go some way in explaining the high placebo-response rates in treatment trials. However, there is a 40% probability of recurrence within 2 years, increasing to up to 70% after 5 years. The likelihood of further episodes in adulthood is about 60% to 70%.5 Thus MDD should optimally be
conceptualized as a chronic condition with remissions and recurrences, more similar to asthma or epilepsy than to pneumonia. This has important but often ignored implications for management, which should seek not only to reduce the duration of the depressive episode and lessen its consequences but also to prevent recurrences. The rate of switching to hypomania in young people with depression also seems higher than in adults, with some researchers claiming rates as high as 40%.13

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