The present study investigated the relationship between adolescent depression, levels of sleep and family functioning in a nationally representative sample of adolescents. Participants were selected from the National Longitudinal Study of Adolescent Health (Add Health) and were split into two separate groups: those who reported getting insufficient amounts of sleep (i.e., 1 to 6 hours/night), and those who reported getting typical amounts of sleep (7 to 10 hours/night). Primary results indicated significant negative relationships between depression and relationships with mother, father and family connectedness. Additionally, for the low-sleep males, a significant negative relationship was found between depression and positive relationship with father, and for low-sleep females, a significant negative relationship was found between depression and a positive relationship with mother and with high levels of family connectedness. Collectively, these results indicate that positive perceptions of parent and family relationships seem to help adolescents avoid depression when they are concurrently experiencing problematic sleep.
Key words: depression; sleep; adolescents; family support
Depression is characterised by a chronic and persistent sadness or loss of enjoyment in normal activities (Baker 1995; Costello et al. 2008; Kendall, Cantwell & Kazdin 1989), and it is typically caused by a complex interplay of genetic, psychological and interpersonal factors. Although the symptoms of depression are problematic at any age, depression in adolescents is particularly troublesome because it can lead to both concurrent and lifelong difficulties. In adolescence, depression has been shown to be concomitant with other psychosocial adjustment problems, including low self-esteem, negative body image and poor academic functioning (Lehtinen et al. 2006; Paxton et al. 2006); depression can be particularly damaging for children and adolescents whose burgeoning growth patterns are still inchoate.
During adolescence, when many teenagers experience increased stress related to the drastic changes occurring in their physical, cognitive, social and emotional growth, some will respond to these changes in troubling ways, including the development of depressive symptomatology. Georgiades et al. (2006) suggested that when compared to younger children, early adolescents experience significantly higher levels of general depressed mood, often caused by rapid developmental changes associated with the onset of early adolescence. Further, Horowitz and Garber (2006) pointed out that depression is thought to affect 1 to 2% of all pre-pubertal children, as compared to anywhere from 3 to 8% of adolescents. Georgiades et al. (2006) concluded that, by middle to late adolescence, levels of major depressive disorder (MDD) often approach those levels found in adult populations. The National Institute of Mental Health (2000) estimated that prevalence rates among adolescents are often as high as 8.3%, with others (e.g., Baker 1995; Kessler & Wakers 1998) suggesting the rate to be even higher at around 10 to 12%. In extreme cases, depression can often lead to suicide with Modroin-McCarthy and Dalton (1996) reporting that suicide is the third leading cause of death among 15- to 24-year-olds.
Because depression is so problematic for adolescents, some researchers have focused on identifying typical risk factors associated with adolescent onset depression (e.g., Reinherz et al. 1999), and other researchers have sought to understand the variables that may buffer adolescents from depression (Mueller 2009). Although risk factors and buffering variables typically associated with depression include a combination of physiological, psychological and environmental factors (Bouma et al. 2008; Costello et al. 2008; MacPhee & Andrews 2006), the current study focuses on how family relationships and average amount of sleep obtained per night may be related to adolescent depression. As discussed in the next few sections, previous research has shown how these factors may independently be related to adolescent depression. For reasons outlined later, there is reason to believe that these factors may also work together to influence adolescent depression.
DEPRESSION AND FAMILY RELATIONSHIPS
Family relationships are particularly important to consider because previous research has also shown that for adolescents, parental and family connectedness tends to predict overall healthy development because of the continued need for warmth and support during the tumultuous adolescent years (Freeman & Brown 2001; Ge et al. 1994). Contrary to the notion that parental involvement becomes less important as adolescents age (e.g., Ainsworth 1989), there are a multitude of studies that have shown how parental warmth and support can act to buffer adolescents from depressive symptomatology (Bean, Barber & Crane 2006; Ge et al. 1994; Stice, Ragan & Randall 2004; Zimmerman et al. 2000). Still others have found that high levels of family cohesion and close family relations may be particularly important buffers to depression for adolescent females (Carbonell, Reinherz & Geinconia 1998; Carbondl et al. 2002). In the context of the present study, this is particularly important because of the discrepancy that has been found between males and females in lifetime prevalence rates of depression (Bogner & Gallo 2004). In a comprehensive review of the literature in this area, Sheeber et al. (2007) concluded: 'The most widely reported finding with regard to family processes is that depression is inversely related to the level of support, attachment and approval adolescents experience in the family environment' (p 144). Thus, for the adolescent, perceptions of family support appear to be vital for overall healthy development and prevention of depression. This may be especially true for adolescent females (Ge et al. 1994).
DEPRESSION AND SLEEP
In addition to family relationships, sleep is another important factor that is associated with adolescent depression. There is a growing body of literature that has explored the link between sleep and depressive symptomatology (Dahl & Lewin 2002; McCracken 2002), particularly during adolescence (Danner 2000). Problematic sleep, including sleep deprivation, may impact the prefrontal cortex which is associated with the ability to control and understand emotions. Sleep deprived individuals may have difficulty with emotional lability, increased feelings of irritability and mood disturbance. This may increase susceptibility to mood disorders such as those associated with depressive symptoms. Chokroverty (1999) suggested that sleep deprivation may impact upon the ability to efficiently cycle through normal stages of sleep and that this chronic disruption in sleep patterns may influence mood. In particular, frequent awakenings or disturbances in the REM stage of sleep may cause deleterious effects on mood and regulation of emotion (Dahl & Lewin 2002).
Biological indicators of the relationship between unipolar depression and sleep deprivation have also been found when comparing EEG (electroencephalograph) readings of depressed versus non-depressed adolescents (Rao et al. 1996). These findings indicated that disturbances occurred in REM sleep in the adolescents who developed depression. McCracken (2002) also reviewed the literature related to depression and disturbances in the architecture (i.e., stages) of sleep. He suggested that the disturbances in sleep may be a risk factor for depression, and he hypothesised that one possible aetiology of adolescent depression may be disrupted sleep patterns. However, Roberts, Roberts and Chen (2002) indicated that there is ambiguity about the cause and effect relationship between depression and sleep deprivation, and Dahl and Lewin (2002) stated that the interaction between sleep and depression is complex. Thus, it remains unclear if sleep deprivation leads to adolescent depression and depressive symptomatology or if these somehow cause sleep deprivation.
Although etiologic pathways are ambiguous, the relationship between adolescent depression and sleep problems is an important psychosocial consideration. According to the American Psychiatric Association (2000; DSM-IV-TR), one criterion for a major depressive episode is insomnia or hypersomnia nearly every day for a period of at least 2 weeks. This may be particularly relevant for adolescents due to the prevalence of sleep deprivation among this population. Approximately 75% of adolescents diagnosed with major depressive disorder report symptoms of insomnia (Dahl 1995). Further, symptoms of depression appear to be exacerbated by an increase in sleep deprivation; adolescents who report sleeping less than 7 hours/night tend to report increased symptoms of depression. Suicide risk may also be linked to sleep deprivation. Roberts, Roberts and Chen (2001) found that suicidal ideation was strongly associated with insomnia and hypersomnia among adolescents. Adolescent sleep deprivation and disturbance is problematic independent of any other psychosocial stressors which may occur during teenage years. When other mental health or relational concerns exist in tandem with sleep problems, the compounding impact on adolescent functioning is significant. Poor sleep is often related to depressive symptoms and anxiety, lowered cognitive and academic functioning, and some tentative links have been established between family functioning and sleep quality of adolescents (Roberts et al. 2001; 2002). …