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Editorial Indian Pediatrics 2001; 38: 1211-1216 |
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Depressive Disorders in the Child and Adolescent Population |
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Epidemiology Population studies have reported prevalence rates of depressive disorders, ranging between 0.4% to 2.5% in children and 0.4% to 8.3% in adolescents(4,5). Dysthymic disorders are shown to have a point prevalence rate varying from, 0.6% to 1.7% in children and 1.6% to 8.0% in adolescents(6). The lifetime prevalence rate of major depressive disorder in adolescents has been estimated to range from 15% to 20%, comparable with the lifetime rate of depressive disorders in adults, suggesting that depression in adults often begins in adolescence(7). In children MDD occur at approximately the same rate in girls and in boys, but in adolescents the female: male ratio is 2:1, again similar to that in adults(8). It appears that individuals born in the latter half of the 20th century are at a greater risk of developing mood disorder especially mild to moderate depression, and these are manifest-ing at a younger age(9). Unfortunately, there are no adequate epidemiological studies in this population, in the Indian setting. Early Versus Late Onset Depressive Disorder Early onset depression is viewed as a continuum with the adult form on the basis of evidences such as: clinical similarities in both populations(10), adult MDD often has its first episode in adolescence(11), increased rates of recurrences of depression in adult-hood for those who had their first episode in adolescence(11) and genetic evidence show-ing increased rates of depression in relatives of depressed children, compared with relatives of non-depressed children(11). At the same time, there are several differences in the characteristics of the disease, between the early onset versus late onset variants. These are, infrequency of melancholic features, a high switch rate to mania of 30%(12), neuro-endocrine differences such as, lack of basal cortisol hypersecretion(13) and a consistent lack of response to Tricyclic Antidepressants (TCA’s), unlike in the adult population(12,14). Clinical Features While some of the clinical characteristics are similar to that of adults, the symptoms of separation anxiety, phobias, somatic complaints and behavioral problems seem to occur more commonly in children(2). Features of endogenicity or melancholia, psychosis, suicidal attempts and dysfunction increase with age. Unlike in adults, psychotic depression in children more often presents with auditory hallucinations than delusions. This has been attributed to the lack of cognitive maturation in children(10). Seasonal affective disorders, atypical depres-sion and premenstrual dysphoric disorders are more commonly seen in adolescence and early adulthood(15). Hypersomnia is less likely in children than adolescents, and anorexia and weight loss is subject to developmental variations(10,16). However, there are other studies that do not find this consistently(11). Childhood dysthymia is noted to have more of irritable mood, feelings of being unloved, anger, self-depreciation, somatic complaints, anxiety, school refusal and disobedience rather than melancholic symptoms, as is commonly seen in adults(17) (Table I). Co-morbidity Epidemiological and clinical studies show that up to 40% to 70% of depressed children and adolescents have one co-morbid diagno-sis, and about 20% to 50% have two or more co-morbid diagnosis(8). These are commonly, dysthymic disorder, anxiety disorders, disruptive disorders and substance abuse. Usually substance abuse starts after the depressive disorder. Conduct problems are a common co-morbidity and tends to persist even after the depression lifts(8). Personality disorders, especially borderline personality disorder, can be co-morbid to a depressive episode, and interestingly, this tends to disappear once the depression has lifted(11). In dysthymic disorders the common co-morbid diagnoses include, depressive episodes, anxiety disorders, conduct disorders and enuresis or encopresis(17). Table I__ Symptoms of Depression in the Child and Adolescent Population
Treatment Given the developmental and psycho-social context in which depression unfolds, a multimodal treatment approach is recommended(2). Psychotherapeutic interventions alone are a well-accepted modality of therapy in child and adolescent depression, where very often, academic difficulties, environmental changes and parental psychopathology act as major stress factors in precipitating and perpetuating depressive symptomatology(2). Further, psychotherapy appears to be a useful initial acute treatment for mild to moderate depres-sion(18). Although, most types of psycho-therapies have been tried, including psycho-dynamic, interpersonal, cognitive-behavioral, family therapy, supportive therapy, and group therapy, no significant outcome differences have been established among individual methods. However, these have been better than no therapy at all. Controlled trials of each are still underway(2). However, a fairly high relapse rate of approximately 40 to 60% was almost common to the different types of psychotherapies(2). There are not many well-conducted studies looking at the efficacy of antidepressant drug therapy in children and adolescents suffering from depressive disorders(19). There are examples of failed studies utilizing both tricyclic antidepressants and Selective Serotonin Reuptake Inhibitors (SSRI)(11). At present, there is no definite evidence to say that pharmacotherapy with antidepressants, especially the most studied tricyclics, are in any way superior to psycho-therapy alone or even, placebos(19). Review articles(2) of studies on the usefulness of tricyclic antidepressants (TCA) in pediatric depression have shown that not only is it no better than placebo, they further have potentially serious cardiovascular complica-tions(19). The reasons attributed to the apparent non-responsiveness of TCA’s in the pediatric population are that: in contrast to the serotonergic and cholinergic systems, the nor-adrenergic systems are not fully developed until early adulthood, in adolescence high gonadal steroidal levels may significantly inhibit the monoamine neuro-transmitters functioning and more depressed adolescents show transition into bipolar disorders than adults and bipolar disorder is less responsive to TCA’s(19). In the recent years, SSRI’s have been tried in the treatment of the child and adolescent populations(11). SSRI’s are favored over the TCAs because of a more benign side effect profile, lower lethality after an overdose and ease of administration. The landmark study by Emslie et al.(11) was the first double blind placebo controlled, randomized trial, to demonstrate the short-term efficacy of any antidepressant over placebo in this age group. However, in the same study complete remission was noted in only 31% of subjects on the fluoxetine arm, while 23% of those on the placebo arm also reached complete remission. Subsequently, an international randomized trial using Sertraline is under way, including sites in India, randomizing the largest number of pediatric subjects with major depression, so far. Trials using other antidepressants are few and have many methodological problems. Various workers have tried Venlafaxine, MAOI’s, Nefezo-done, Mirtazapine and Reboxetine, all in open trials with variable results(11). Further Phase III trials using newer agents such as Sub-stance P Receptor Antagonists, Corticotropin Releasing Hormone Type I Receptor Anta-gonists and Neurosteroids, may hold promise for the future(11). The current ongoing trials may come up with an indicated drug in this population (Table II). Most randomized placebo controlled studies with antidepressants that are demonstrated to be effective in adults, have shown that when tried in the pediatric population, the placebo response rates in children and adolescents is about 50-70%, in contrast to placebo response rates in depressed adults of only 30-40%(11). This may be due to instability of affective symptoms in the pediatric population, low prevalence of melancholic depression among children and adolescents and high prevalence of co-morbid conditions especially disruptive disorders. However, the recurrence rate of depressive disorders in this population is significantly higher than that in the adults.
The mean length of an episode of depres-sion appears to be between 7 to 9 months(8). However, it appears to be a recurrent condition with a cumulative probability of recurrence of 40% by 2 years and 70% by 5 years(8). About 20% to 40% develop bipolar disorders within a period of 5 years(11). Early onset dysthymic disorders have a mean episode length of about 4 years and are associated with a tendency to MDD (70%), bipolar disorder (13%), and substance abuse (15%)(17). Sequelae As a consequence of the depressive episode, the children show impairment in school performance, disruptive behavior and strained family relationships(21). Further, depression in this population has been shown to be associated with increased risk of suicidal behavior, homicidal ideation, tobacco use and other substance abuse into adulthood. Prospectively, even after recovery, these children continue to show negative attributes, impaired interpersonal relationships, in-creased smoking, impairment in global functioning, early pregnancy and increased physical problems(21). Current evidence shows that depressive disorder in the child and adolescent popula-tion is a separate entity from adult depressive disorders and has several differences but also similarities with the latter. These disorders are often not picked up early enough, and have a high morbidity and mortality. Although many treatment options are currently available, there is no single best treatment option. These disorders show a high rate of recurrence and co-morbidity, with significant ongoing psychosocial impairments. Early recognition and effective management is crucial to prevent dangerous sequelae.
Thomas John,
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