To our knowledge this is the first study examining the lifetime prevalence and demographic, clinical and family correlates of physical and/or sexual abuse in children and adolescents with BP spectrum disorders. About one in five subjects had physical and/or sexual abuse. The most robust correlates of any abuse history in this sample of BP youth were non-intact family, PTSD, CD, psychosis and first degree family history of mood disorder.
As compared with the non-abused group, physical abuse was significantly associated with longer duration of BP illness, living with a non-intact family, higher rates of PTSD and psychosis, and first-degree relatives with mood disorder. Sexual abuse was only associated with greater prevalence of PTSD. Having both types of abuse was associated with older age, longer duration of the illness, non-intact family, and greater prevalence of PTSD and CD.
Before discussing the above-noted results it is important to note the limitations of the study. First, although the data was collected during childhood or adolescence, the possibility of retrospective recall bias remains. For example, abuse at a very early age may be more likely to be forgotten. Also parents and their children may not report the abuse because of embarrassment or desire to protect the perpetrator (Fergusson et al.,2000
). Second, since this is a cross-sectional study, we cannot infer causality or relationship between two variables in time. It is possible that individuals who have been abused are at higher risk for developing psychiatric disturbance. Alternatively, individuals who have BP may be at higher risk for abuse as a result of exposure to higher risk situations. Third, the implications of lifetime abuse on the course and outcome of BP were not evaluated. However, we are prospectively following the sample, which will allow a more precise estimate of the association between abuse and clinical course and outcome in BP youths. Fourth, this study did not systematically assess for severity or frequency of abuse, relationship of the subject to the perpetrator identified, family history of abuse and other forms of abuse such as emotional abuse. Finally, no psychiatric control group was included. Thus, we cannot conclude that abuse is more common in BP youth than in other childhood psychiatric disorders.
To our knowledge, there are no studies of sexual/physical abuse in BP children and only one study has examined the prevalence of sexual and physical abuse in sample of youth (n=165) ages 6 to 17 years old with other non-BP psychiatric disorders (Ford et al., 2000
). In this study, the rates of physical and/or sexual abuse were 10 % for adjustment disorders, 36% for ADHD and 66% for ODD. However, due to important differences in methodology between this and our study, we were not able to compare the result. Similar to the rates of any abuse in the adolescents with BP, epidemiological studies have also shown approximately 20% prevalence of sexual and physical abuse in adolescents (Diaz et al., 2002
; Hussey et al., 2006
; May-Chahal and Cawson, 2005
). However, it is important to note that in contrast to our study, some of these studies defined physical assault more broadly (e.g., being “slapped, hit or kicked) (Hussey et al., 2006
Our results are similar to those recently reported by the Stanley Foundation Bipolar Network (SFBN) in adults with BP (Leverich et al., 2002
). For example, after adjusting for age, subjects with history of any abuse showed longer duration of illness as compared to those without abuse. Also, similar to the SFBN finding that half of the adults with any abuse history were both physically and sexually abused, in our sample about 35 % of the children and adolescents reporting physical abuse were also sexually abused, and about 42% of children and adolescents sexually abused were also physically abused (Leverich et al., 2002
). However, in contrast with the adult literature, we did not find that earlier age of BP onset was associated with a higher prevalence of abuse and there were no sex differences in the sexual and physical abuse group compared to the non-abused group, (Leverich et al., 2002
). Also, the rates of childhood sexual and physical abuse in youth with bipolar disorder found were about half of the rates reported in the BP adult literature (20% vs. 45%) (Brown et al., 2005
; Leverich et al., 2002
). Possible explanations for these differences include age with adults having increased likelihood of abuse, recall bias, different methods of assessing abuse (questionnaire vs. semi structured interview), and/or the inclusion of patients with adult-onset bipolar who for obvious reasons were not included in our sample.
The finding that any type of abuse is independently significantly associated with PTSD converges with data from youth in the general population (Widom, 1999
). The lifetime prevalence of PTSD among any abused youth in the present study was 20%, similar to the PTSD rates (20%–35%) reported in BP adults with history of childhood physical or sexual abuse (Goldberg and Garno, 2005
; Leverich et al., 2002
). A recent study reported high rates of PTSD (38%) mainly due to sexual abuse in a small sample of adolescents with BP when compared with adolescents with major depressive disorder (14%) and non-affective controls (4%) (Dilsaver et al., 2007
). The prevalence of sexual abuse in this study was not reported precluding comparisons with our results.
The finding that psychosis is independently significantly associated with any abuse also converges with previous findings from the general population (Janssen et al., 2004
) and from subjects with schizophrenia (Read et al., 2005
). Similar to our results, recent findings from the National Comorbidity Survey indicate a significant independent association between physical abuse and psychosis (OR=2.7) (Shevlin et al., 2007
). The odds ratio reported in that study were similar in magnitude to those found in the association between physical abuse and psychosis in the COBY sample. However, findings on the association between abuse and psychosis in adults with BP are mixed (Brown et al., 2005
; Garno et al., 2005
; Hammersley et al., 2003
; Leverich et al., 2002
As has been suggested in the “traumagenic neurodevelopmental model”, (Read et al., 2001
) early trauma may negatively affect the developing brain. Specifically, hyper-responsivity of the hypothalamic-pituitary-adrenal (HPA) axis may result in altered dopaminergic and serotonergic system function. This model may explain why bipolar children who have been abused are more likely to present psychotic symptoms as compared to those who have not been abused.
Consistent with findings from community and clinical studies (Livingston, 1987
; Luntz and Widom, 1994
; Widom, 1989
) comorbid conduct disorder was associated with history of abuse in BP youth. Future prospective studies from the COBY sample will be able to inform about the direction of this association.
Studies have shown that sexual abuse appears to mediate the transmission of suicide attempt in the offspring of mood disordered suicide attempters (Brent et al., 2002
). Also substance abuse has been associated with sexual and physical abuse (Leverich et al., 2002
). However, after adjusting for between-group differences in demographic and clinical factors, we did not find significant differences in the rates of suicide attempts and substance abuse. However, it is important to note that the average age of our sample was around 12 and consequently many subjects have not yet passed the timeframe for increased risk of substance abuse or suicidal attempts. Prospective follow up of the COBY sample will also indicate whether or not abuse is a predictor of suicide attempts and/or substance abuse.
Finally, bipolar youth with history of any abuse were more likely to have family history of mood disorders, substance abuse, and conduct disorder in their first-degree relatives as compared with the non-abused group. After logistic regression analysis family history of mood disorder in first-degree relatives remained associated with history of any abuse. These results are comparable to those reported in pediatric community and clinical samples (Chaffin et al., 1996
; Kaufman et al., 1998
; Kim-Cohen et al., 2006
). Furthermore, our results concur with those reported in the SFBN among adults with BP finding a higher family history of mood disorder, substance abuse, and other non-affective disorders in first-degree relatives in abused BP subjects (Leverich et al., 2002
To summarize, present findings highlight the need for careful assessment of abuse in youth with bipolar spectrum disorders, as well as the importance of early identification and intervention and preventative measures for those at risk (Post and Leverich, 2006
). Prospective studies are necessary to fully understand the impact that abuse may have in the course and outcome of early-onset BP. These studies will also help to identify risk factors or paths of vulnerability for abuse among BP youth.