Adolescent Depression: Causes, Neurobiology, and Treatment

Introduction

Adolescent depression is a common mental and emotional disorder that affects both teens and young adults. Medically, there is no difference between adult depression and adolescent depression. The symptoms of this condition, however, manifest differently in adolescents than they do in adults. This can be attributed to the several challenges teens face as they grow older (Brian, 2012). The various ups and downs experienced by teenagers are affected by sports affiliation, changing hormones, peer pressure, awkward social tendencies, developing bodies, and a host of other factors. These variations are often indications of depression. Depression is accompanied by symptoms such as anxiety, stress, and, in worst cases, suicidal ideation. This condition can affect every aspect of a teenager's life — work, school, social, and family life — which can often lead to social isolation and related problems.

The encouraging news, however, is that people affected by depression can recover. It is one of those rare medical conditions that is capable of affecting every dimension of a person's life, yet it is also one that is manageable with proper care. Both adult and adolescent depression can also be referred to as major depressive disorder (MDD). In a summary provided by Young (2012), adolescent depression remains a major public health issue. It is therefore important that adolescents suffering mild, moderate, moderately severe, or very severe depression receive the appropriate help and attention for each stage, because the stages are not identical and require different levels of care.

Implications of Considering Diverse Populations

In a study undertaken across different segments of society in Minnesota to evaluate the correlation between obesity and Major Depressive Disorder (MDD), researchers observed depressive symptoms emerging as early as age 14 in obese teens. The phenomenon extended into late adolescence and among early adults aged 20–24. For girls specifically, obesity posed a greater risk of depression, and this risk changed over the lifetime (Marmorstein, Iacono, & Legrand, 2014). Park and Rosenstein (2015) examined cancer and depression as separate conditions, yet noted that both are responsible for enormous human suffering on a worldwide scale. In 2008, an estimated 169 million healthy life-years were lost due to cancer worldwide. By 2030, the World Health Organization foresees that major unipolar depression will become the leading cause of disease burden. A Danish cancer registry reported that patients over the age of 15 have a higher risk of developing depression severe enough to require hospitalization within the first year following a cancer diagnosis.

Williams, Teasdale, Segal, and Cabot-Zinn (2007) note that approximately 20% of females and 12% of males will encounter serious depression at least once in their lifetime. They further contend that a prior episode of depression significantly raises the likelihood of a subsequent bout. According to research conducted at Stanford University, girls tend to express their problems by talking about them openly, crying, or otherwise making them known, which makes identification and subsequent intervention easier than it is for boys.

Implications of Crisis and Trauma on Depressive Adolescents

According to Stewart et al. (2015), in 2013 more than 1,500 American adolescents committed suicide, making it the second leading cause of death among individuals between the ages of 13 and 18. For every completed suicide among youth, there are an estimated 100–200 failed attempts (Crosby et al., 2011). A recent epidemiological study indicated that 4.1% of adolescents make at least one attempt by the age of 18 (Nock et al., 2013). Mood disorders, particularly MDD, are well-established risk factors for suicidal behavior, and among adolescents with MDD, there is a six-fold greater risk of suicide attempts compared to non-depressed youth (Nock et al., 2013). Given these disturbing rates, identifying core risk factors for suicidal behavior in this age group is essential (Brian, 2012).

Thapar (2012) considers unipolar depression a major depressive disorder affecting millions of Americans each year, with the actual number likely higher since many affected individuals are never formally recorded. This type of depression is more prevalent in girls, increases sharply following puberty, and toward the end of adolescence the one-year incidence rate exceeds four percent. Depression leads to serious educational and social impairments.

Skrove et al. (2013) attempted to estimate the occurrence of anxiety and depression symptoms in a large adolescent population and to explore their connection to lifestyle factors. The researchers also investigated whether resilience factors weakened the relationship between unhealthy lifestyle choices and symptoms of anxiety and depression. They found that adolescent depression and anxiety have a direct correspondence with physical inactivity and substance abuse. Resilience had a marked influence in diminishing this correspondence. Social support, especially from family, played a role in preventing negative influences on adolescents.

Danielsson et al. (2013) conducted a study to investigate whether catastrophic worry mediates the relationship between adolescent sleep disturbances and depressive symptoms. The findings firmly established the connection between sleep disturbance and depression. Sleep disturbance was found to precede anxiety and depression by approximately one year, and catastrophic worry acted as a catalyst in this relationship between sleep disturbance and symptoms of anxiety and depression in adolescents.

Conclusion and Future Directions

Studies carried out over the last three decades have demonstrated the ability of psychotherapy to address adolescent depression effectively. Cognitive-behavioral models have been tested extensively and rigorously, and there is evidence in support of family-based therapy and interpersonal psychotherapy. The vast majority of studies, however, have focused on short-term treatment of depressive episodes — this is despite accumulating evidence that depression is a persistent condition that often continues into adulthood. Treatment research also shows that adolescents who respond to interventions more quickly and completely achieve more effective long-term relief and recovery.

Park and Rosenstein (2015) summarize that adolescents and young adults remain an understudied and underserved population, despite increasing global cancer rates and the associated depression risk. The development of major depressive disorder in adolescents with cancer warrants further research. More studies should be developed in the future to better understand the unique factors causing depression in this and related groups.

Given what is currently known about adolescent treatment, and in light of what previous studies have failed to determine, future psychotherapy research should take a longer-term outlook and focus on the following challenges:

(a) The prevention of relapse and recurring episodes, while improving the thoroughness and speed of first response to treatment;

(b) Discovering the important treatment components and learning processes that result in effective and long-lasting recovery from depressive disorders;

(c) Ascertaining whether, and how, to address co-morbid disorders during the course of depression treatment;

(d) Addressing the dilemma of complexity versus simplicity in treatment techniques. Given the limited number of proven treatment methods currently available, all new techniques ought to be rigorously investigated.

These new models should be examined against older models and compared to available medications and combined (medication plus psychotherapy) treatments. Investigators now have the advantage of improving the dissemination of findings, conducting experimental psychotherapeutics, and extending online intervention platforms to meet the primary goals of relapse prevention and sustained recovery.