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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

Complex trauma arises from events that happen repeatedly and are difficult to escape from, such as war, childhood abuse and violence. People may experience post-traumatic stress disorder (PTSD), depression, anxiety, and other mental health issues. Mental health services are ill-equipped to help them, due to a lack of clear evidence on the best therapies for people with complex trauma.

A major new review assessed the evidence on treatment approaches used for complex trauma. Further in-depth research is warranted for the most promising.

The report found that psychological therapies were effective and acceptable for reducing PTSD, depression, and anxiety. However, the quality of the evidence was low or unclear.

Antipsychotic medicines were effective for treating the symptoms of PTSD. But researchers found little evidence for the effectiveness of any other medication.

This review forms the basis for new clinical trials to further explore the best therapies for people affected by complex trauma.

What’s the issue?

PTSD is a form of anxiety that can cause flashbacks, insomnia, and long-lasting emotions such as anger and guilt. It is estimated to affect 4 in 100 people in England.

PTSD often results from a single traumatic event. But regular, repeated traumatic events, such as childhood abuse and domestic violence, can lead to complex PTSD and other mental health conditions.

There are effective psychological approaches and medicines for treating single event PTSD. But it is not known whether these treatments also benefit people with a history of complex traumatic events. As a result, the NHS is ill-prepared to help people who have experienced complex trauma.

This review set out to identify which treatments are most effective and acceptable for this group of people. The researchers wanted to identify the frontrunners for more in-depth research.

What’s new?

The team reviewed scientific research on a range of different therapies for complex trauma.

Their review included 104 controlled trials, and nine other trials, on the effectiveness of psychological treatments and medications. A further nine studies explored the acceptability of treatments in interviews and focus groups. Participants were veterans, civilians affected by war, refugees, and people who had experienced childhood sexual abuse or domestic violence.

Psychological therapies were effective in treating the symptoms of PTSD, depression, and anxiety. These interventions included long-established techniques such as cognitive behavioural therapy (CBT) but also newer trauma-focussed interventions such as eye movement desensitisation and reprocessing therapy (EMDR). In EMDR, people are asked to recall a disturbing event while moving their eyes side-to-side following their therapist’s finger; the therapist helps the person shift their focus to more pleasant thoughts. It is not clear how this works but it can help people change the way they think about a traumatic experience.

The study found drop-out rates from psychological approaches were low and concluded that these approaches were acceptable to participants.

Phase-based approaches aim to develop emotional strength and a sense of safety before complex trauma is addressed. They might include mindfulness and relaxation. There was some evidence that phase-based approaches helped people with the most complex trauma, such as those with histories of childhood sexual abuse. They helped tackle the symptoms of PTSD and improved participants’ ability to control their emotions and interact with others.

The researchers found differences between the patient groups. Psychological therapies were most effective for those affected by domestic violence. They were less effective for veterans, civilians affected by war and people who had experienced childhood sexual abuse. Multicomponent approaches that use a mixture of different therapies appeared to work better for these groups.

The researchers reviewed six trials about drug treatments, five of which studied veterans. Only antipsychotic medicine was effective in reducing PTSD symptoms in this group. No medicines reduced symptoms of depression or psychosis.

Why is this important?

This report found that existing psychological therapies are effective and acceptable ways to manage mental health in people with complex trauma. But it remains unclear what combinations of psychological therapies are most effective.

This report highlights the need for more research into psychological and phase-based interventions for complex trauma.

Researchers also need to identify the best way of helping the groups of people who responded less well to these treatments.

What’s next?

The report highlights the lack of research into treatments for people with complex PTSD. Many of the studies included in the review were of low quality. High quality research is needed.

The reasons why people with a history of complex trauma do not seek treatment need to be explored; research into the lived experiences of these people is vital.

Many of the studies reviewed in this research assessed treatments only in the short-term and did not follow participants beyond six months. Research should explore the effects of treatment, including safety, over the longer-term.

A key aim of this research was to identify future targets for research. During an online open day, the team discussed their findings with practitioners and service providers working in the field of complex trauma. Attendees voted on which research should be prioritised.

Following on from this research, the NIHR released a themed funding call for research into psychological interventions for complex PTSD.

You may be interested to read

The full paper: Melton H, and others. Interventions for adults with a history of complex traumatic events: the INCiTE mixed-methods systematic review. Health Technol Assess. 2020;24:1-312

Paper focussing on the quantitative elements of the study: Coventry PA, and others. Psychological and pharmacological interventions for posttraumatic stress disorder and comorbid mental health problems following complex traumatic events: Systematic review and component network meta-analysis. PLoS Med. 2020;17:e1003262

The Mental Elf, a service that provides information on mental health research and guidance, helped organise the research team’s dissemination open day

NHS information on post-traumatic stress disorder (PTSD) and complex PTSD


Funding: This project was funded by the NIHR Health Technology Assessment programme.

Conflicts of Interest: Peter Coventry is a member of the HTA General Board (2018–19) and Health Services and Delivery Research Funding Committee Members (2019–21).

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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