Trajectories of depressive symptoms during the transition to young adulthood: The role of chronic illness

Abstract

Background

Little is known about the natural course of depressive symptoms among youth with chronic illness during their transition from adolescence to young adulthood.

Methods

A representative epidemiological sample of 2825 youth aged 10–11 years from the National Longitudinal Survey of Children and Youth were followed until 24–25 years of age. Presence of chronic illness was measured using self-report and symptoms of depression were assessed using the Center for Epidemiological Studies Depression Scale. Multilevel modeling was used to investigate trajectories of depressive symptoms, adjusting for family environment and sociodemographic characteristics during the transition to young adulthood.

Results

Trajectories showed cubic change over time – increasing from early to mid-adolescence, decreasing to early young adulthood, increasing again to late young adulthood. Youth with chronic illness (n=753) had significantly less favorable trajectories and significantly higher proportions of clinically relevant depressive symptoms over time compared to their peers without chronic illness (n=2072).

Limitations

This study is limited by selective attrition, self-reported chronic illness and no assessment of illness severity, and mediating effects of family environment factors could not be examined.

Conclusions

Findings support the diathesis-stress model; chronic illness negatively influenced depressive symptoms trajectories, such that youth with chronic illness had higher depression scores and less favorable trajectories over time. The health and school system are uniquely positioned to support youth with chronic illness navigate this developmental period in an effort to prevent declines in mental health.

Introduction

Improvements in the medical treatment of youth with a chronic illness have led to increased rates of survival – 90% of these youth live into adulthood (Ontario Association of Community Care Access , 2013, Perrin et al., 2007). However, there are no known cures for many of these conditions and so youth with chronic illness still face considerable challenges to their psychological well-being (Moreira et al., 2013). In addition to experiencing poorer quality of life (Moreira et al., 2013), meta-analytic evidence suggests that youth with chronic illness have significantly higher rates of mental health problems compared to healthy children (Boyce et al., 2009, Pinquart and Shen, 2011a, Pinquart and Shen, 2011b), including depression (Pinquart and Shen, 2011b, Pinquart and Shen, 2011c). The elevated risk for mental health problems and depression specifically among youth with chronic illness is consistent with current theories linking physical and mental health. According to cognitive-behavioral theories, negatively biased thought patterns that exaggerate risk and associated harm of illness exacerbations, as well as an underestimated ability to handle potentially threatening situations, produce symptoms of depression and anxiety (Beck et al., 1985). For example, the experience of unpredictable asthma attacks or seizures can lead to a state of learned helplessness and burden that can lead to episodes of depression (Chaney et al., 1999, Hoppe and Elger, 2011). Furthermore, the diathesis-stress model suggests that youth with chronic illness are exposed to higher allostatic load, which results in adverse effects on mental health (Bahreinian et al., 2013, McEwen, 1998, Monroe and Simons, 1991).

During adolescence and young adulthood, the 12-month prevalence of depression increases from 2% in childhood to 20% (Costello et al., 2002, Kessler and Walters, 1998). Developmental processes that may explain this rise in prevalence include puberty-related hormonal changes, increased capacity for self-reflection and rumination associated with cognitive maturation, increased psychological stress resulting from normative developmental transitions, and changing relationships with parents and peers (Ge et al., 2001, Hankin et al., 2007, Koenig and Gladstone, 1998, Nolen-Hoeksema and Girgus, 1994). In addition, imaging studies have shown that the brain continues to organize, adapt, and change in adolescence – in fact, the changes that occur in the brain during the transitions from childhood to adolescence to young adulthood are particularly dramatic (Jetha and Segalowitz, 2012). Given the evidence that depressive episodes first appear in adolescence (Costello et al., 2005) and that early age at onset predicts longer duration (Kovacs et al., 1984), adolescence and young adulthood is a critical period for identification, prevention, and intervention.

While there is strong evidence supporting the increase in risk of depression during the transition from childhood to adolescence (Costello et al., 2005, Costello et al., 2002), epidemiological studies examining symptoms of depression during the transition to young adulthood have produced more heterogeneous findings with respect to trajectories of change over time. Early research suggested that rates of clinical depression were low from early to middle adolescence, then increased dramatically in late adolescence, and remained high into young adulthood (Hankin et al., 1998). In contrast, other researchers reported linear declines in symptoms of depression among emerging adults aged 18–25 years (Galambos et al., 2006). Using more sophisticated analyses (i.e., growth curve modeling), researchers have shown symptoms of depression to be much more dynamic during this period of development, reporting curvilinear trajectories of symptoms that tend to peak between middle and late adolescence (Natsuaki et al., 2009, Rawana and Morgan, 2014). Extending these findings, other researchers have used latent class growth modeling to show that some heterogeneity exists in the trajectories of depressive symptoms of adolescents transitioning to young adulthood (Costello et al., 2008, Frye and Rossignol, 2011).

Despite the progress made in understanding changes in depressive symptoms during the transition to young adulthood in general population samples of youth, there is virtually no information on this phenomenon among youth with chronic illness. Most longitudinal studies examining mental health trajectories among individuals with chronic illness have typically sampled adults, not youth (Hasler et al., 2005, Oga et al., 2007). Findings from a few short-term longitudinal studies ranging from one to three years in clinical samples of children and young adolescents with chronic illness, suggest that symptoms of depression fluctuate considerably, but typically display a curvilinear ‘U-shaped’ trajectory (Austin et al., 2011, Grey et al., 1995, Helgeson et al., 2007, Jaser et al., 2012). One prospective clinical study of 10 years duration followed a small sample of youth aged 8-13 years with new-onset diabetes and reported that the prevalence of depression was highest in the first year after diagnosis (Kovacs et al., 1997). Prevalence of depression followed the typical ‘U-shape’ described in the short-term studies. One epidemiological study which investigated the psychological distress of youth with asthma and epilepsy followed from 16-25 years of age showed that youth with asthma or epilepsy were at elevated risk for psychological distress compared to healthy controls during the 10-year follow-up (Ferro, 2013). Risk peaked between the ages of 18–20 years. While youth with epilepsy reported more psychological distress compared to youth with asthma, the differences were not statistically significant, supporting the view that mental health problems in youth with chronic illness are partially a result of the shared effects of having a chronic illness.

Contemporary estimates suggest that over 13% of youth have a mental health problem (Waddell et al., 2014). Depression and anxiety are the most common conditions, comprising nearly 70% of mental disorder diagnoses in youth (Merikangas et al., 2010, Waddell et al., 2014). Chronic illnesses affect nearly 20% of youth (van der Lee et al., 2007). Although prevalence estimates of youth with multimorbidity (i.e., youth with physical and mental comorbidity) are difficult to obtain, general population studies suggest that approximately 11% of youth have physical-mental multimorbidity (Britt et al., 2008, Ferro, submitted for publication, Harrison et al., 2014, van den Akker et al., 1998). In a U.S. study that sampled youth from several public sectors (e.g., justice, welfare), 51% of youth with anxiety had a chronic illness, with asthma, epilepsy, diabetes, and gastrointestinal problems being the most common (Chavira et al., 2008). Data from the 1983 Ontario Child Health Study found that among children 4–16 years with a chronic illness and functional limitation, 33% had one or more mental health problems; among those with a chronic illness only, the prevalence of mental health problems was 23% (Cadman et al., 1987). Compared to youth with a mental health problems only, youth with multimorbidity were more likely to have been receiving care at a mental health clinic (11% vs. 28%) (Cadman et al., 1987).

Multimorbidity has extraordinary importance not only for the general population, but also for the health care system; it is associated with increased mortality (Gijsen et al., 2001), poor functioning (Bayliss et al., 2003), lower quality of life (Fortin et al., 2006), and high health care use (Le et al., 2011, Reigada et al., 2011). In addition, mental health outcomes are poorer for those with multimorbidity. For example, individuals with diabetes are less likely to achieve remission of their depression than those without (Bryan et al., 2010) and despite consuming significantly more health resources ($19,707 vs. $11,237 per year), individuals with depression and diabetes are more likely to be diagnosed with another mental comorbidity (Le et al., 2011). Thus, examining the unique perspective of youth with chronic illness is needed to understand the natural course of symptoms of depression and to inform the coordination of health services aimed at the prevention of deteriorating mental health during the period of development from adolescence to young adulthood (Crowley et al., 2011).

The objective of this epidemiological study was to prospectively assess the course of depressive symptoms in a representative sample of youth with and without chronic illness during their transition to young adulthood. Specifically, our aim was to estimate and compare trajectories of depressive symptoms between youth with and without chronic illness during the transition from adolescence (12–13 years) to young adulthood (24–25 years). Given our knowledge of current theory and previous empirical findings, we hypothesized that trajectories will be different for youth with chronic illness compared to those without, whereby youth with chronic illness would report higher initial levels of depressive symptoms and would experience a less favorable trajectory over time.