Interdependent psychological quality of life in dyads adjusting to prostate cancer.

Prostate cancer is the most commonly diagnosed cancer in men. Although the death rate from prostate cancer continues to decline, the incidence of prostate cancer is increasing, due in part to improved screening. With early diagnosis prostate cancer is highly treatable, but men with prostate cancer often experience troublesome side effects associated with treatment that negatively influence their quality of life (QOL) (Penson, Litwin, & Aaronson, 2003). Side effects associated with prostate cancer treatment include urinary incontinence, erectile dysfunction, loss of libido, fatigue, and hot flashes (Stanford et al., 2000). Sexual dysfunction after treatment for prostate cancer is particularly associated with psychological distress in survivors (Wootten et al., 2007). Fatigue is experienced at some point in time by most men treated for prostate cancer (Danjoux, Gardner, & Fitch, 2007). This constellation of side effects contributes to significant psychological distress that is experienced by at least one third of men with prostate cancer (Balderson & Towell, 2003). Between 25–50% of men have substantial problems with anxiety and associated feelings of nervousness and worrying associated with prostate cancer (Korfage, Essink-Bot, Janssens, Schroder, & de Koning, 2006; Mehnert, Lehmann, Schulte, & Koch, 2007). Although some treatments for prostate cancer are associated with unique side effects, problems such as depression, anxiety, and fatigue appear with comparable frequency in survivors across a range of different treatment modalities (Harrington, Hansen, Moskowitz, Todd, & Feuerstein, 2010; Maliski, Kwan, Elashoff, & Litwin, 2008; Steineck et al., 2002). In some cancer survivors, psychological distress can persist for periods as long as 1 to 10 years (Harrington et al., 2010; Traeger et al., 2009). In addition, prostate cancer often occurs later in life when other comorbid health conditions occur that further complicate health related QOL (Karakiewicz et al., 2008). The psychological distress that often accompanies prostate cancer and interferes with QOL is not just experienced by cancer survivors themselves. The effects of cancer and its treatment can cause dramatic changes in relationships, roles, and psychological health for survivors as well as their partners and family members. Partners of men with prostate cancer report a major decline in the family’s overall QOL after diagnosis (Mellon & Northouse, 2001). Wives of men with prostate cancer often experience anxiety, stress, depression, and uncertainty along with the physical symptoms that accompany such emotions (Aranda & Hayman-White, 2001; Garos, Kluck, & Aronoff, 2007). These problems are especially pronounced during advanced stages of prostate cancer (Northouse et al., 2007). In some cases spouses of men treated for prostate cancer report higher levels of distress than the men themselves (Eton, Lepore, & Helgeson, 2005). Factors such as low self-esteem, less positive coping strategies, lower marital quality, and dysfunctional problem-solving increase the risk of distress in spouses of men with prostate cancer (Eton et al., 2005; Ko et al., 2005). Many of the prostate specific functional impairments that are often experienced by men undergoing prostate cancer treatment such as urinary, bowel, and sexual dysfunction can be distressing to their partners (Eton et al., 2005; Ezer et al., 2006; Sanda et al., 2008) just as they are to survivors themselves. Although problems such as sexual dysfunction have obvious implications for intimate partners’ QOL, urinary and bowel problems could also affect the QOL of other supportive partners who provide care and assistance to survivors (e.g., laundry, running errands). Such effects provide some explanation for how and why prostate cancer survivors and their partners experience interdependent QOL. Research on the psychological QOL of cancer survivors and their supportive partners has significant implications for understanding theories of emotional contagion. Emotional contagion is at least one mechanism that could create dyadic interdependence in psychological QOL indicators among prostate cancer survivors and their partners. According to the emotional contagion hypothesis, people catch the intense emotional states of those with whom they interact through largely unconscious interpersonal processes (Hatfield, Cacioppo, & Rapson, 1992, 1994). Emotional contagion theorists observe that people will mimic and synchronize their nonverbal behaviors with those of the people around them. This similarity in behavior is theorized to provide feedback that generates the same emotional experience as those people whose behaviors are being observed and matched. Social comparison processes have also been advanced as an explanation for emotional contagion (Epstude & Mussweiler, 2009). An important implication of the social comparison effect is that similarly between the actor and observer is theorized to increase the likelihood of emotional contagion. This suggests for example that emotional contagion could be particularly likely in marital and other close relationships where people share numerous similarities (Goodman & Shippy, 2002). Cancer survivors and their supportive partners represent a useful context for testing emotional contagion effects. As previously noted, similarity would be expected to be higher than average in these close relationships, enhancing the probability of emotional contagion. Further, members of these dyads are coping with a common stressor. Encountering a common threat has been shown to increase emotional contagion (Gump & Kulik, 1997). It is therefore understandable why meta-analytic evidence shows a correlation between cancer survivors’ and their spouses’ distress, although this effect appears strongest when the survivor is female (Hagedoorn, Sanderman, Bolks, Tuinstra, & Coyne, 2008), and why family members and intimate partners often experience the same or higher levels of emotional distress (e.g., depression, anxiety) as cancer survivors (Manne et al., 2007; Rabin et al., 2009). There is reason to believe that the psychological distress of cancer patients is related to that of their partners or immediate family members. When advanced cancer patients meet the criteria for psychiatric disorder, their caregivers, 75% of whom were spouses, were 7.9 times more likely to meet the criteria as well, and vice versa (Bambauer et al., 2006). This increased odds ratio was based on concurrent data, but controlled for demographic characteristics and lifetime psychiatric disorders in patients. In women with breast cancer and their supportive partners, 63% of whom were spouses, the psychological distress of one partner predicts the subsequent distress of the other (Segrin, Badger, Dorros, Meek, & Lopez, 2007; Segrin et al., 2005). These dyadic effects were demonstrated over two 6-week intervals, controlling for prior psychological distress in the survivor and partner, as well as preexisting dyadic interdependence in distress at baseline. Surprisingly, results for the Segrin et al. investigations showed that the direction of influence is more commonly from the partner to the survivor. In other words, partners’ psychological distress predicts subsequent psychological distress in survivors. Studies of dyadic interdependence in psychological distress and QOL associated with breast cancer most often measure psychological distress in female survivors and male partners. In dyads where one member has cancer or some other serious illness, there are commonly sex differences such that women, be they patients or caregivers, report more psychological distress than men (Hagedoorn et al., 2008; Thompson et al., 2004). Accordingly, it may be possible that psychological distress is more easily transmitted to women than it is to men, regardless of their role in the dyad (i.e., patient or partner). Studying dyadic interdependence in the context of prostate cancer allows for an examination of the potential transmission of psychological distress within the dyad, in a context where gender roles are reversed in comparison to dyads coping with breast cancer. The primary aim of this investigation is to examine the extent to which there is dyadic interdependence in psychological distress within dyads coping with prostate cancer and its treatment. In the present study, dyadic interdependence in psychological QOL was examined in two ways. First, we assessed the association between prostate specific health related QOL issues (e.g., urinary functioning, sexual functioning) in survivors and psychological QOL in their partners. Although these elements of QOL would certainly be expected to predict psychological distress in prostate cancer survivors, the extent to which they are related to the distress of survivors’ partners is less certain. Second, we tested for dyadic interdependence in psychological distress longitudinally, in dyads participating in a 3-wave longitudinal study of 16 weeks duration. These analyses allow for a stringent test of the extent to which one dyad member’s psychological distress influences that of the other dyad member as they cope with and adjust to prostate cancer and its treatment related side effects. In this investigation, psychological QOL was operationalized with a variety of indicators that reflect the type of psychological (depression, anxiety) and somatic (fatigue) distress that is commonly experienced by cancer patients. In addition, we included a measure of positive affect, as psychological QOL entails more than the mere absence of negative states, but the experience of positive emotions as well.