Auden wrote around the time of the war, and many of his poems include salutary lessons about and deep insights into the experience of soldiers and refugees in conflict situations (‘Refugee Blues’ for example). It is almost impossible to not notice the linking of stories on migration and the refugee crisis and the immediacy of terrorist threats on global news channels and in the press. November 2015 will be remembered for terrorist attacks in Paris and Mali. The attacks galvanised world governments to take a unified position on preventing and countering all brands of terrorism. The colours of the French flag have become idiomatic of resistance and resilience, and many have found solace in expressions of unity. This unity has also mobilised governments collectively to consider more actions, including air strikes in Syria. Overall, a cohesive, proportionate and dignified response is more likely to subvert the terrorist strategy that seeks to provoke extreme measures and consequential political unrest that might emerge in response to oppressive, discriminatory, draconian or persecuting measures. There are also media lessons to learn, to perhaps not overreport, a little like careful reporting of suicidal events to avoid epidemics, or more thoughtful language for describing mental illness to combat stigma. Despite humanitarian responses, at the same time there is a perceived threat from migrants and refugees; freedom of movement across borders in the EU is now proposed to explain how the Paris attacks were planned and executed in different countries. The risks of mental illness among migrants, refugees, victims of trauma and torture, those exposed to war and conflict are well established, so we might expect greater demands on mental health and social care services. Yet, following Paris, more resources will be committed to counter-terrorism, demonstrating a wider impact of terrorism on public health through the loss of investment and greater strain on public finance.

As with all extreme and rare events, predicting terrorist attacks and countering them is not easy, and the evidence base for doing so is evolving and largely focused on those who have already raised suspicion about risk and threat to public safety. The impact on mental health is both through raised worries about the levels of perceived threat as well as the direct effects of trauma, loss, and shattered moral frameworks that are not easily restored. Other victims include those facing exodus and forced migration, perhaps fleeing conflict zones, by negotiating risky journeys and threats to their safety, identity and anticipated life plans. Children who face such experiences are unable to process powerful affects that arise in response to conflict are therefore more especially vulnerable. ¹ Garralda's editorial in this issue (pp. ) highlights how trauma might be a determinant of hallucinations, some of which may be clinically relevant.

Violence in general is a major global threat to public health, especially gender-related violence and violence towards children and young people. Thirty-five per cent of women worldwide report intimate partner violence or non-partner sexual violence, and 30% of women in a relationship report physical or sexual violence by their partner; risk factors include low education, witnessing violence between parents, exposure to abuse during childhood and attitudes accepting violence and gender inequality. ² WHO suggests there are evidence-based primary preventive interventions including school-based programmes in high- and low-income countries, microfinance combined with community initiatives tackling gender inequality; and improving communication and relationship skills. Furthermore, prevention should also target situations of conflict, post-conflict and displacement, as women often suffer more violence in such situations.

Prevention of violent offending is a priority on which we need more evidence and insights from research in forensic psychiatry. Fazel et al's 10-country study (pp. ) of over 12 000 people discharged from secure hospital shows significant mortality, suicide, readmission and reoffending rates, with recommendations for more targeted preventive interventions. Ouellet-Morin et al's longitudinal study (pp. ) shows that MAOA gene-related risks of future antisocial behaviour interact with the levels of violence to which young children were exposed. Children exposed to war, conflict and forced migration surely are at risk of such outcomes and this mandates preventive interventions at times of conflict. Adversity may trigger stress pathways that contribute to risks of future psychosis, perhaps through sympathetic and parasympathetic moderation. New research shows low vagal tone to be important, as it may explain the very common finding of poor emotional regulation and impaired executive function in schizophrenia (Clamor et al, pp. ). Childhood adversity may also explain obsessive–compulsive disorder (OCD); Brooks et al (pp. ) report that larger brain volumes may reflect neurodevelopmental pathology in adults with OCD, driven perhaps by historical experiences of childhood adversity.

This issue of the BJPsych also reports new findings on affective disorders, dementia, and OCD. Alzheimer's disease and dementia generally are a major threat to public health, although good scientific progress is now being made on better identifying the role of amyloid protein (see Harrison & Owen, pp. ). Identifying endophenotypes should help improve targeting of future treatments. For example, López-Solà et al (pp. ) show complex phenotypes of comorbid anxiety and OCD. Previous studies of ethnic density show low associations with higher risks of schizophrenia and self-harm but the study by Du Preez et al (pp. ) suggests no associations with postnatal depression and personality in general. Visual impairment seems important for the development of seasonal affective disorder and this may help to better understand affective disorders more generally (Madsen et al, pp. ). Suicidal thoughts and anxiety persist longer in those with the melancholic subtype of depression (Lamers et al, pp. ), offering an opportunity to better identify this subgroup for more active and intensive treatment. Two interventions for affective disorders seem to be very effective: functional remediation improves psychosocial outcomes in bipolar disorder (Bonnin et al, pp. ) and internet-based acceptance and commitment therapy in depression (Potts et al, pp. ). Yatham et al's study of adjunctive treatments in acute bipolar depression (pp. ) shows that agomelatine is no better than placebo, an important negative finding with definitive treatment consequences.

A clear positive or negative finding helps to improve practice, and so psychiatric research is flourishing producing incremental advances, yet in contrast, we know so little about terrorism and why people attack the countries in which they are raised and secure. Better knowledge, research and preventive applications of psychiatric, forensic and behavioural sciences must be given as much priority as counter-terrorism and preparedness if we are to truly prevent and protect, and nurture positive mental health.