Experts around the globe are calling for a joint effort to tackle the world's leading cause of suffering and disability - mental health disorders. Nearly 450 million people have mental health disorders and more than three-quarters live in developing countries. According to the World Health Organization (WHO), eight in every 10 of those living in developing nations receive no treatment at all. Many are the survivors of infectious diseases, natural disasters and war. In Afghanistan, most families have lost one or more member during the country's 30 years of conflict. And it's estimated about half of Afghanis over 15 years of age have mental health problems such as depression, anxiety or post-traumatic stress disorder. Outside of the country's capital Kabul there is no mental healthcare system. Neglect Afghanistan is not alone - almost half of the world's population lives in a country where, on average, there is one psychiatrist or fewer to serve 200,000 people. Many low-income countries have less than one mental health specialist per one million population, according to the WHO. In Nigeria, a quarter of patients seen in local health centres have significant depression symptoms yet few are diagnosed and only one in six of those who are diagnosed get treatment of any kind. In other parts of Africa, like the Ghanaian capital Accra, patients in some mental health institutions are left hungry and naked. Each country faces its own set of challenges. In Ethiopia, a major cause of mental stress is domestic violence, which is thought to occur in more than two-thirds of rural families. Meanwhile people living in Haiti are having to come to terms with the devastation of the 2010 earthquake that killed more than 300,000 people, injured another 300,000 and left 1.6 million homeless. Almost every person on the island was affected. Later that same year a cholera outbreak killed another 6,000 inhabitants. In May 2012, health ministers from the member states of the World Health Assembly agreed to a resolution on mental health, making a commitment to promote greater awareness of mental health issues and improve care standards around the world. Mobile help A global mental health action plan is now being drawn up. The Canadian government has said it will give nearly $20m (£12.5m) to support 15 new projects designed to improve mental health diagnosis and care in developing countries. The projects, led by Grand Challenges Canada, will tackle issues that can lead to mental illness, such as alcohol and substance abuse, as well as delivering solutions like counselling and health promotion. One project will use mobile phones to deliver instant and accessible support to Nigerian women suffering from postnatal depression. Another will use local health networks and telemedicine to help Afghanis with mental health conditions. Dr Peter Singer, of Grand Challenges Canada, said: "There is very little funding for mental health innovations in low-and middle-income countries, where mental illness is the most neglected of many neglected diseases. "It's a terrible denial of human potential."