Major Depressive Disorder in Children and Adolescents : Etiologies , Course , Gender Differences , and Treatments

Within the last decade, research has supported the notion that Major Depressive Disorder (MDD) can occur in children and adolescents as well as in adults. This paper elaborates on the trends of the current literature concerning the etiologies, course, gender differences, and recommended treatment approaches for early onset MDD. Can children and young adolescents be clinically depressed? This is a question that mental health professionals and researchers have answered very differently within the past few decades. In fact, although the older research states that children cannot be clinically depressed, the literature within the last 10 years maintains that youngsters Ideas and Research You Can Use: VISTAS 2013 2 actually can experience and be diagnosed with Major Depressive Disorder (MDD; Costello, Erkanli & Angold, 2006). MDD is a mood disorder characterized by “a clinical course of one or more Major Depressive Episodes without a history of Manic, Mixed, or Hypomanic Episodes” (Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000, p. 369). These multiple episodes consist of a persistent change in mood with manifested symptoms of depressed or irritable moods, loss of interest and pleasure in once-loved activities, and other additional behaviors (4th ed., text rev.; DSM–IV–TR; American Psychiatric Association, 2000). These are some of the characteristics that make up the diagnostic criteria for MDD, but recognizing the disorder in children and adolescents is different from doing so in adults. This discrepancy is due to the numerous differences in the developmental stages and makeup between child and adult populations. Due to the significant change in perspectives within the recent years concerning early onset MDD (Costello et al., 2006), it is important to understand and recognize the symptoms of MDD in youth so that these children will be able to receive appropriate treatment. It is also vital to understand the etiology and course of MDD in children and adolescents while still taking into account the effects that gender has on the manifestation of the disorder. Further, along with all of these aspects considered, it is imperative to know what the most recommended and supported treatments are for this population. Although professionals typically use the same diagnostic criteria for MDD in children as they do for adults, it is more complicated when trying to assess whether or not a child has this disorder since youngsters may not be able to fully verbalize and explain their emotions and symptoms. As stated in the DSM-IV-TR (2000), a Major Depressive Episode in a child or adolescent may manifest itself through irritability rather than the typical sad mood experienced by adults. Children may also not be able to verbally express their feelings of depression and only behaviorally exhibit their depression (e.g., tantrums, frustration, somatic issues). The somatic complaints that depressed children oftentimes have include stomachaches, headaches, various pains, etc. (Emslie & Mayes, 1999), and they may also suffer from low self-esteem, feelings of guilt, or persistent boredom; may speak of or have efforts to run away from home; may have decreased interest in previously favorite activities; and may exhibit frequent sadness, tearfulness, or crying (American Academy of Child and Adolescent Psychiatry, 2010). There can also be some atypical symptoms that appear, such as “increased reactivity to rejection, lethargy, increased appetite, craving for carbohydrates, and hypersomnia” (Cheng & Myers, 2010, p. 178). Overall, however, the recent literature consistently maintains the importance of considering irritability as a symptom of childhood MDD (Birmaher et al., 2007; Fava et al., 2010). Some of the symptoms of depression in adolescents are similar to those seen in younger children, but there is usually more emphasis on interpersonal conflicts in the former age group. For instance, Meichenbaum (2010) states that some symptoms could be loss of friendships, trouble or breakup of relationships, not getting along with family members, and higher than normal levels of expressed emotions. In some cases, adolescents can show symptoms of a physical illness that may be a sign of clinical depression. Any of these situations can be both a cause and a result of depression Ideas and Research You Can Use: VISTAS 2013 3 (Meichenbaum, 2010). As in children, a major symptom of MDD that is typically seen in adolescents is irritability (Fava et al., 2010). The assessment for pediatric depression can be difficult, as it is not always clearcut. As Cheng and Myers (2010) explain, the presentation of depression in this age group can vary depending on the child’s unique development, experiences, and physical health. Clinicians must also ensure that symptoms such as fatigue, difficulty sleeping, or somatic complaints are not due to an underlying medical condition. Differential diagnoses must be kept in mind as well, as depression is oftentimes co-morbid with other behavioral disorders that require treatment. Concerning differential diagnoses, it is common for youth with eating disorders or anxiety to initially present with depressive symptoms (Cheng & Myers, 2010). Etiology The etiology of MDD in children and adolescents is not straightforward either, as it is not attributed to or explained by a single, distinct factor. Rather, the disorder is usually brought about by the complex interaction of many factors. These etiologies include neurological, genetic, environmental, psychosocial, and psychological aspects of the child (Abela & Hankin, 2008). These realms interact in intricate and unique ways to produce the possible outcome of MDD. Within the neurological domain, Goodyer (2008) explains that the roles of three neuroactive chemical components are particularly influential in the etiology of depressive disorders like MDD in youngsters. These components are serotonin, brain-deprived neurotrophic factor (BDNF), and cortisol. Abnormal levels of these factors can lead to depressive symptoms within the first few years of life, especially as the neurological chemicals relate to the amygdala and ventral prefrontal cortex. This, in turn, can alter the regulation of mood and emotion in children and adolescents, thereby leading to depressive symptoms and disorders such as MDD. Goodyer goes on to explain that later disruptions in neural development, termed acquired neuroendangerment, can also lead to similar outcomes. This particular occurrence is “a pathological brain process leading to reduced synaptic plasticity, in particular in the hippocampus and perhaps the nucleus accumbens and ventral tegmentum” (Goodyer, 2008, p. 1239). At any point in life, especially within the presence of environmental stressors, deficits within the motivational, cognitive, and behavioral realms may result from this neural disruption. Also within the neurological realm, recent research has found linkages between 5HTTLPR (a serotonin transporter genotype) and MDD during adolescence. Specifically, differences in biochemistry and behavior have been observed in individuals with varying 5-HTTLPR genotypes. This discovery suggests that 5-HTTLPR “may be partially responsible for differential biological stress reactivity and that behavioral differences between those carrying the S versus L allele may be most prominent in stressful situations” (Petersen et al., 2012, p. 2). Stress and anxiety have been consistently shown to be predictors of subsequent depression, and since individuals react to stress differently, it is more likely that individuals with 5-HTTLPR-S alleles would be more prone than Lallele carriers to experience anxiety and develop depression following stress. These “findings demonstrate that the 5-HTTLPR genotype affects likelihood of experiencing anxious/depressed symptoms in situations of stress, particularly during late adolescence” (Petersen et al., 2012, pp. 13-14). If future findings support this 5-HTTLPR Gene × Stress Ideas and Research You Can Use: VISTAS 2013 4 interaction, more effective assessment tools could possibly be developed to identify and target at-risk individuals for treatment (Petersen et al., 2012). Another neurological influence for depression in youth concerns the hypothalamic-pituitary-adrenal (HPA) axis, which triggers an increase in cortisol levels when a stressful or threatening event occurs (Guerry & Hastings, 2011). Specifically, Guerry and Hastings (2011) note that there is abundant evidence showing that dysregulation of this axis is a large contributor to MDD in adults. These researchers discuss multiple studies and conclude that there is evidence that the HPA axis plays a significant role in depressive disorders of children and adolescents as well. These influences from the HPA axis come into play through various means, including genetic inheritances (especially maternal depression) and cortisol-releasing responses to psychological stressors. Despite these possible evidences, Guerry and Hastings (2001) report there is a large need for more longitudinal research to determine whether developmental changes in HPA functioning could account in part for the dramatic increases in the rates of depression from childhood to adolescence. They further note that future research needs to determine if dysregulation of the HPA axis is a correlate, cause, or consequence of childhood MDD. Genetic influences also play vital roles in the etiology of MDD in children and adolescents. Schreier, Höfler, Wittchen, and Lieb (2006) discuss several studies that have consistently demonstrated a familial pattern of MDD, and they also state that various twin studies have supported this notion of genetic influence. However, they add that the environmental factors within the family must also be taken into account when considering the role of genetics in childhood MDD. Similarly, in studying adolescent twi