Fran Lowry

April 29, 2013

ORLANDO, Florida — Emotional abuse experienced in childhood, especially in children aged 5 years and younger, confers an increased risk for bipolar disorder, new research shows.

"Our results show the importance of childhood trauma, not only as a risk factor for bipolar disorders per se but also for a more severe clinical and dimensional profile of expression of the disorder," author Monica Aas, PhD, from the University of Oslo, in Norway, told Medscape Medical News.

The findings were presented here at the 14th International Congress on Schizophrenia Research (ICOSR).

Bipolar disorder is due in part to genetic risk variants, but it is also likely to be due in part to environmental susceptibility factors. Among these, childhood trauma has been proposed as a likely environmental factor, Dr. Aas said.

"We wanted to look into it because we know that patients with bipolar disorder seem to have a high prevalence of childhood trauma, and there is also evidence in the literature that this may be related to clinical symptoms," she said.

Dr. Monica Aas

Most studies focus on physical and sexual abuse and neglect emotional abuse as a possible contributing factor to the development of bipolar disorders, Dr. Aas added.

Two-fold Increased Risk

To address the issue, the investigators, led by Bruno Etain, MD, Groupe Hospitalier Henri Mondor, Pôle de Psychiatrie and Inserm, Créteil, France, first assessed 206 bipolar patients and 94 control participants in a case-control study using the Childhood Trauma Questionnaire.

The questionnaire asked about emotional abuse, sexual abuse, physical abuse, emotional neglect, and physical neglect.

Next, they recruited 587 consecutive patients with bipolar disorders from France and Norway and again used the Childhood Trauma Questionnaire to analyze various clinical features.

Finally, they used the Affective Lability Scale and the Affect Intensity Measure to link childhood trauma and affective instability in adulthood.

Compared with control individuals, multiple trauma occurred almost twice as frequently in patients with bipolar disorder (63% for patients vs 33% for control participants).

When the researchers looked further, they found that only emotional abuse was associated with bipolar disorder.

Regression analysis showed that children who were emotionally abused were more than twice as likely to develop bipolar disorder (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.51 - 3.02).

Dose-Dependent Effect

Additionally, the greater the severity of the emotional abuse, the higher the rate of subsequent bipolar disorder, Dr. Aas said.

Emotional and sexual abuse were also associated with younger age of onset, more suicide attempts, more rapid cycling, and greater proneness to depression.

Children who were emotionally or sexually abused had the most attempts at suicide compared with those who were not abused (OR = 1.60, 95% CI, 1.07 - 2.39 for emotional abuse, and OR = 1.80, 95% CI, 1.14 - 2.86 for sexual abuse).

The investigators also found that sexual abuse was the strongest predictor of rapid cycling, with an OR of 1.92 (95% CI, 1.14 - 3.24).

In addition, the more that children were exposed to trauma in childhood, the higher the level of affective instability, according to the Affective Lability Scale and the Affect Intensity Measure.

"We hope that clinicians will take into account the occurrence of childhood emotional abuse when they see children, because it is even more significant as a cause of psychiatric disability than physical abuse," Dr. Aas said.

Clinically Useful

Commenting on the findings for Medscape Medical News, Richard Drake, MD, PhD, senior lecturer at University of Manchester, in the United Kingdom, said the finding that emotional abuse was so strongly linked to the development of bipolar disorder was "interesting."

Dr. Richard Drake

The work brings together large studies of different aspects of the relationship between childhood trauma and bipolar disorder. This gives an indication not only of what aspects of childhood abuse are most important in driving the relationship with the illness but also what aspects of bipolar disorder seem most directly related to emotional abuse as the main driver, he said.

But, he cautioned: "This is retrospective data, and of course that makes one cautious in interpreting the results. If this was done prospectively, the same findings may not come up."

Dr. Drake agreed that the findings can be useful to practitioners.

"We all have patients who have various forms of abuse. Trying to tease apart what we can expect as a result of that, and what the relationship is between the abuse and the outcome and where we might best intervene, is of direct value in clinical practice."

Dr. Aas, Dr. Etain, and Dr. Drake report no relevant financial relationships.

14th International Congress on Schizophrenia Research (ICOSR). Abstract S18. Presented April 24, 2013.

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