'Mental and neurological disorders are a major issue in terms of the absolute number of patients and the diseases' burden,' Wang Xiangdong, a mental health adviser, told AFP.
According to a WHO report, mental and neurological disorders in 2002 accounted for 17.6 percent of the total disease burden in the WHO's Western Pacific region, with depression alone responsible for more than six percent.
There were about 331,000 suicides in the region that year, the latest for which full data is available.
Worldwide, suicide accounts for 33 percent of all violent deaths among men and 57 percent among women, the WHO has said.
'They (mental and neurological disorders) create a major and unnecessary burden for individuals, communities and societies,' the WHO's regional committee for the Western Pacific said in the report.
The committee is holding its annual meeting this week in South Korea's Jeju island.
Regional director Shigeru Omi, in a speech Monday, said the Western Pacific 'continues to bear a disproportionate share of the world's suicide burden'.
The report urges member states to note the 'increasing trend of mental, behavioural, neurological and substance abuse'.
It calls on member states to continue considering mental health as a priority 'and to continue to increase political, financial, and technical commitment in order to address mental, behavioural and neurological diseases.'
Wang said he believed the rise in the incidence of mental disease was faster than in other regions, but added it was not a priority for most member states.
The allocation for mental and neurological disorders is less than one percent of the total health budget in half of the countries and areas in the Western Pacific, according to the WHO.
A WHO survey conducted between 2001 and 2003 found that 76-85 percent of mental patients in less developed countries had received no treatment in the previous year, compared with 35-50 percent in developed countries.
'We cannot expect their health budgets to jump to match the disease's burden but clearly, one percent is not sufficient,' Wang said.
He said many countries in the region lacked mental health policies or legislation. Many people believe mental disease is a remote risk until friends or family suddenly fall victim.
Social stigmas cause many people in the region not to seek help and make the problems worse, Wang said.
'Just like hypertension, you need full and continuous treatment for those diseases. Otherwise, you cannot prevent relapses. That's a very important point,' he said.