Child maltreatment could predict a range of negative outcomes in patients with bipolar disorder (BD), according to new King's College London research, which adds to growing evidence on the enduring mental health impact of childhood abuse and neglect.

A meta-analysis of 30 studies found that bipolar patients with a history of childhood maltreatment developed BD more than four years earlier than patients with no history of maltreatment. In addition, they were almost twice as likely to attempt suicide and nearly four times more likely to have a diagnosis of post-traumatic stress disorder (PTSD).

One in every 25 adults will be diagnosed with bipolar disorder at some point in their life. The disorder is characterised by periods or episodes of feeling very low and lethargic (depression) or of feeling very high and overactive (mania). Bipolar disorder carries the highest risk of suicide among affective disorders: up to 15 per cent of people with bipolar disorder die by suicide. However, not all bipolar patients have these particularly severe outcomes, and there is wide variability in clinical presentation.

Therefore, it is important to identify bipolar patients with the greatest clinical need and risk as early as possible, in order to ensure that they receive the most timely and effective interventions to reduce their risk of poor outcomes.

Maltreatment in the form of physical, sexual or emotional abuse, or neglect, affects one in five children under 18 in the UK and is known to be highly prevalent in bipolar patients (up to 60 percent). Maltreatment predicts negative outcomes in depressed patients, but it was previously unclear if information on maltreatment could help identify early those bipolar patients with greater clinical needs and risk.

The study, published in The Lancet Psychiatry, found that bipolar patients with a history of childhood maltreatment had more severe manic, depressive and psychotic symptoms; higher risk of post-traumatic stress disorder (PTSD), anxiety disorders, and substance and alcohol misuse disorders; earlier onset of symptoms; more frequent manic and depressive episodes; and higher risk of suicide attempt.

Dr Jessica Agnew-Blais, Post-doctoral Researcher from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London and lead author of the study, said: 'These findings lend support to the notion that maltreatment can affect neurobiological processes associated with progression of the disorder.

'Our findings have important implications for clinical practice, as they suggest that a history of childhood maltreatment could be used as an early indicator of high risk for poor outcomes among individuals with bipolar disorder. This information could be valuable for identifying patients with bipolar disorder who may benefit from greater support and treatment.'

Dr Andrea Danese, Senior Lecturer from the IoPPN at King's College London and senior author of the study, said: 'Future research should identify mechanisms that link childhood maltreatment to unfavourable clinical outcomes in BD, which is associated with disability and life-threatening risks.

'We hope this study will point to vulnerabilities that could inform innovative treatment strategies for people with BD, including anti-inflammatory medications or treatments aimed at trauma and anxiety-related symptoms.'

Dr Danese added: 'Further studies are also needed to assess whether childhood maltreatment predicts treatment response among patients with BD, as has been suggested by early research in this area.'