Borrowing books was a privilege introduced for women by several academic institutions and libraries in England in the 19th century. Cambridge University accepted women on equal terms with men in 1948. Various objectors before that feared that higher education would have untoward effects on women's bodies and minds. The eminent 19th-century psychiatrist Henry Maudsley was convinced it would make them infertile (Robinson, 2009). Yet women played an important role in the founding of many Islamic educational institutions from the first millennium, and Christian religious orders fostered education for girls and women in Europe before the modern era.

Over the past 20 years the number of children recruited into armed conflict, as combatants, spies, labourers and sex slaves, has increased substantially (Wessells, 2009). In this issue, we focus on the research that has been done in recent years to identify the extent of this problem and, in particular, the efforts that are being made to discover the most effective ways of rehabilitating former child soldiers into society.

Worldwide there are currently 300 000 child soldiers. Not only does the use of child soldiers lead to individual suffering but it also alters the dynamics of war and makes conflict and instability more likely. It is important both to prevent recruitment and to rehabilitate former child soldiers into their communities. For rehabilitation and reintegration programmes to be effective, it is necessary to understand the consequences of child soldiering. This paper reviews and summarises some of the key findings related to the mental health consequences of being a child soldier.

Child soldiers represent a challenging population for mental health and psychosocial support (MHPSS), as we have little evidence regarding their needs or the efficacy of interventions. Despite an increasing breadth of MHPSS interventions for children affected by war, very few are supported by evidence (Jordans et al, 2009). In a recent decade-long conflict, Maoists and the government of Nepal conscripted thousands of children to serve as soldiers, sentries, spies, cooks and porters. After the war ended in 2006, we began a project incorporating research into the development of interventions for former child soldiers. Through this work, conducted with Transcultural Psychosocial Organization (TPO) Nepal, we identified four key principles to guide research and intervention with child soldiers (Fig. 1). We present these principles as location- and context-specific examples of the growing effort to develop guidelines and recommendations for research and intervention in acute post-conflict settings (Inter-Agency Standing Committee, 2007; Allden et al, 2009).

The forceful conscription of children (both boys and girls) into armed forces has been documented in at least 86 countries (Coalition to Stop the Use of Child Soldiers, 2008). Research suggests that these children may be at heightened risk of psychological and social problems (Wessells, 2009; Blattman & Annan, 2010). However, there is little information on the long-term effects of child soldiers' wartime experiences.

Hong Kong was a UK colony before 1997 but has since been a Special Administrative Region of the People's Republic of China. It is located in southern China and has an area of 1104 km2. Approximately 95% of Hong Kong's population is ethnic Chinese. Hong Kong is a developed capitalist economy, with a gross domestic product of US$301.6 billion (2009 estimate), of which about 5.5% is spent on healthcare and about 0.24% on mental health (World Health Organization, 2005). Despite the relatively low level of spending on healthcare, Hong Kong nevertheless has one of the longest life expectancies in the world (79.2 years for men; 84.8 years for women) and a very low infant mortality rate (2.93 per 1000 live births) (Central Intelligence Agency, 2010).

Since the mid-1980s, a profound reform in the organisation of mental health provision has been taking place in Greece (Madianos & Christodoulou, 2007; Christodoulou, 2009). The aim has been to modernise the outdated system of care (Christodoulou, 1970), which was based on in-patient asylum-like treatment, the beginning of which can be roughly dated to the second half of the 19th century (Christodoulou et al, 2010).

Ghana is a West African state that attained independence from Great Britain in 1957 and became a republican state in 1960. Its population is about 22 million (2004 estimate), distributed in ten regions. The World Health Organization (WHO) has estimated that 650000 of the population are suffering from severe mental disorder and 2166000 are suffering from moderate to mild mental disorder (see www.who.int/mental_health/policy/country/ghana/en).

Malta is an archipelago (with three inhabited islands) in the Mediterranean Sea. According to the 2006 census, Malta has a population of just over 400000 and is the eighth most densely populated country in the world (1272 persons/km2) and the most densely populated of the member states of the European Union (EU). The most densely populated town in Malta is Senglea, with 22744 persons/km2 (situated in the Southern Harbour Area). In comparison, Malta's sister island, Gozo, has a density of 422 persons/km2. Over 92% of the population lives in urban areas.

The importance of traditional healing in low- and middle-income countries cannot be under estimated. It is generally perceived as part of the prevailing belief system and traditional healers are often seen as the primary agents for psychosocial problems in these countries; estimates of their service share range from 45% to 60% (World Health Organization, 1992). The World Health Organization (2000) estimated that 80% of people living in rural areas in low- and middle-income countries depend on traditional medicine for their health needs.

For many women, pregnancy and childbirth are not without substantial risk in terms of new-onset, recurrent or existing mental disorder. This has consequences not only in terms of poor maternal mental health but also in terms of increased pregnancy- and delivery-related morbidity and can have a significant negative impact on the wellbeing of the fetus or neonate. New-onset disorders such as postnatal depression and puerperal psychosis have been recognised for some considerable time but it is also becoming apparent that, with the exception of anorexia nervosa, severe intellectual disability and possibly schizophrenia, conception rates among women with all types of mental disorder are the same as those in the general population. In high-income countries, the widespread use of atypical antipsychotics, most of which do not impair reproductive function, may lead to increased conception rates in women with schizophrenia. In addition, pregnancy and childbirth are multifactorial stressors which may render women with previous mental disorders vulnerable to a recurrence. Hence it is no surprise that studies in urban, low-income and ethnically diverse populations in the USA estimate that around a third of pregnant women are suffering from a mental disorder when substance misuse is included (e.g. Kim et al, 2006).