The Bank of Scotland study also found that older people and those earning the most are the happiest.
The annual nationwide survey asks Scots how happy or unhappy they are in their local communities, to create an official barometer of contentment ranging between -100 (very unhappy) to +100 (very happy).
Overall, Scots are slightly happier than last year as the Index recorded a score of 44.9 (an increase of 1.2 points compared to 2017) and 5.9 points more cheerful than three years ago.
Central Scotland was the most cheerful place in Scotland in 2018 with a score of 49.82, followed by the Highlands and Islands (47.61) and Lothians (46.23).
West Scotland was bottom of the table with a score of 40.08, while Glasgow was second last at 40.32, though almost 10 points up on last year.
Over-65s remained the happiest age group for the fourth year running, while the happiness levels of 18- to 24-year-olds have grown by the highest number of points in the last year.
Those aged 35 to 44 are at the bottom of the table for the second consecutive year, and 24 points below the over-65s.
Ricky Diggins, director at Bank of Scotland said: “This year’s Index tells a few interesting stories but overall, it’s good to see happiness levels are increasing across the country.
“Despite the fact older generations have stayed at the top of the table, the younger generations appear to be catching up.
“But of course the jewel in the crown this year is Central Scotland, as it takes the top regional spot in this year’s Index.”
The study found that households with two residents were the happiest for the third year running while families of four have slumped four places to the bottom of the table, replacing those living alone, who move up one position to fifth place.
The latest Index found that the more Scots earn, the happier they are.
This year, Scots with a household income of more than £60,000 are happiest.
This is in contrast to 2017 when those with a household income of between £40,000 and £59,999 were top – however they are now in second place.
The research was completed by YouGov who questioned 3,039 adults between December 2017 and January 2018.
Earlier this year, in its annual survey of well-being, the Office for National Statistics said people across the rest of the UK are becoming more unhappy.
Yet the UK’s overall happiness rating has been pushed up thanks to those living in Scotland.
The ONS said: “Scotland has shown improvements in average ratings of life satisfaction, worthwhile and happiness but there have been no overall changes in England, Wales or Northern Ireland.”