[identity profile] strawberryfrog.livejournal.com 2011-11-10 10:16 am (UTC)(link)
Dark, cold evenings and SAD seem (personal anecdotal observation) to have a stronger effect on people raised in more sub-tropical latitudes - e.g. South Africa, Australia - where there is much less seasonal variation in day length.

The first few winters were really bad. After that it's not quite so bad.