Full-time student numbers have risen, but part-time places have fallen dramatically, according to separate reports published by the Scottish Funding Council.
A baseline report on colleges showed that since the SNP came to power in 2007, total student numbers in the college sector had fallen by more than 120,000.
Although full-time student numbers increased by more than 19 per cent between 2007-08 and 2011-12, the 257,913 full- and part-time learners at college in 2011 represented a reduction of 121,320 over the same period.
The figures provoked an angry political reaction from opposition MSPs.
Hugh Henry, Labour's education spokesman, said the "massive cuts" in the numbers of part-time students were hitting the poorest communities hardest.
"The SNP has axed part-time courses and SNP MSPs insult those students by calling them 'hobby courses'. The result is 100,000 fewer Scottish women are in college now than when the SNP came to power," he added.
Liam McArthur, Liberal Democrat education spokesman, described the drop in part-time students as "a real problem for people who want to study part-time, perhaps to juggle family responsibilities or hold down a temporary job at the same time".
The decline in overall student numbers was described as "a major concern", by Conservative education spokeswoman Liz Smith, particularly at a time when employers were asking colleges to provide more courses.
The SFC's College Performance Indicators 2011-12 report reinforced the trend towards providing full-time courses at the expense of "leisure programmes" and short courses lasting for less than 10 hours.
It added: "SFC asked colleges to replace these very short programmes with more substantial programmes of study and to prioritise additional places for those aged 16 to 24 who were not in employment, education or training."
The proportion of students on courses that do not lead to a qualification had also gone down significantly. Only 6 per cent of the total learning hours and 25 per cent of student enrolments were on these courses in 2011-12, a decrease of 40 per cent compared to 2010-11.
John Henderson, chief executive of Colleges Scotland, said the report on performance indicators showed colleges continued to deliver improvements in the outcomes for learners as completion rates were up in almost every category.
"Eighty per cent of those aged 16 to 24 are completing their course of study. We also see 77 per cent of those from the poorest backgrounds, and 80 per cent of those with disabilities, gaining credits and qualifications."
He added: "A high proportion of people studying in colleges start with no qualifications at all, and achieving this level of success is a significant and life-changing achievement for those individuals."
Education secretary Michael Russell said the figures were "excellent news for Scotland's college sector, which is focused on delivering full-time courses to further improve the job prospects of our young people".
The figures demonstrated that colleges had not just fulfilled that role, but had done even more - "exceeding targets, while also being more efficient" - Mr Russell said.
- Full-time student numbers at Scotland's colleges increased by over 19 per cent between 2007-08 and 2011-12
- 121,320 fewer full- and part time students studied at Scotland's colleges in 2011-12, compared with 2007-08
- Full-time student numbers increased from 66,667 in 2005-06 to 81,373 in 2011-12. The majority of these students were funded by the Scottish Funding Council and aged 16-24.
- Disabled students accounted for 15 per cent of all hours of learning in 2011-12.
Scotland's Colleges: A Baseline Report for Academic Year 2011-12, Scottish Funding Council.