Mental health has become one of the rising challenges for the Scottish health service, just as it has throughout the UK and in other countries. For the majority of people, mental health issues first arise when they're still young, with 50% of problems established by age 14. Since 2013, Scotland's specialist child and adolescent mental health services (CAMHS) have experienced a surge of demand of more than 30% - an increase of around 8400 referrals a year. And during that same period, average waiting times for a first treatment appointment have increased from seven to 12 weeks. The Scottish Government points to a £250m investment package in young people's mental health over the next five years - including measures to give them more support in their schools and community before they need to be referred to CAMHS. But the reality is this service is seeing thousands more patients than even a year ago - with thousands more waiting to be seen. In the most recent figures out on Tuesday, it was revealed the number of children and young people waiting more than 12 months for CAMHS has trebled. A total of 118 patients waited 53 weeks or more before starting their treatment in the first three months of 2019. Drilling into the numbers, however, nine out of Scotland's 14 health boards did not have any patients waiting that long to be seen. In fact, 95% of year-long waits originated from just two health boards - NHS Lothian and NHS Fife. Across NHS Lothian, 85 children and young people (10.9% of the total) waited more than a year, up from 30 (4.5%) in the same 2018 period. In NHS Fife, only four people waited more than a year to be seen in the first quarter of 2018 - but that's risen almost sixfold to 27 (9.3% of the total) this year. CAMHS only employs slightly more than 1000 full-time equivalent staff across Scotland, so small local changes to staffing or resources can clearly have a significant impact. It should also be noted that the figures above only apply to patients who have been seen. Of the approximately 10,600 still waiting for first appointments across Scotland in March 2019, 422 have been waiting more than a year. That's 4% of the national total, which has steadily risen from a figure of 1.2% in January 2018, when only 95 patients were waiting that long without being seen. The Scottish Government's aim is for 90% of CAMHS patients to have their first appointment within 18 weeks of referral - or four and a half months. It has never met this target since it was introduced in 2014, recording 80% in 2014/15, with the trend year-on-year generally going the wrong way ever since. In the first quarter of 2019, only 73.6% of children and young people were seen within 18 weeks - although that figure has improved by about 2.5% in the last year. Only four NHS boards met the 90% target - NHS Dumfries and Galloway, NHS Forth Valley, NHS Shetland and NHS Western Isles. In NHS Grampian the proportion of youngsters starting treatment within 18 weeks is just 43.3% - while in NHS Borders it's just two-fifths (40%). Across Scotland, 158 children and young people waited between nine months and a year for their first CAMHS appointment. That's 3.7% of the 4200-odd patients the service has seen in the first three months of 2019. A total of 71 patients came from the NHS Tayside area, where around 17% of the health board's CAMHS patients had to wait that long to start treatment. NHS Lanarkshire had 41 patients waiting nine months to a year to be seen, or 8.4% of their total. For waits of between 18 and 36 weeks, NHS Borders has the highest proportion of them, with 66 patients (60%) having to wait that long for their first appointment. The second highest proportion of 18 to 36-week waits is at NHS Grampian, where 52.8% of patients waited that long - that's 162 children and young people. As the number of mental health referrals for youngsters has gone up and up, so too has the figure of referrals rejected by mental health specialists. In 2018/2019, more than a fifth of referrals (21%) were turned away - around 7600 potential patients. That proportion of rejections has been pretty stable over the last few years. But compared to 2013/14, when 5785 referrals were turned away, that's a rise in volume of about a third (32%) - or 1800 extra rejected referrals.