There is an Ensign article or two from back in the 1970's that are opposed to playing cards so yes such is doctrinal. However, I freely admit to enjoying card playing and I rationalize this because I don't gamble which I think is the spirit of the law.
I'm not into poker but I enjoy hearts and spades. I remember also this big thing against Dungweons and Dragons but my parents got me the "Keep on the Borderlands" basic set when I was 11 or 12 and I played ever since.
I think the cautions against these things are gambling and time wasting; if it becomes your whole life.
Edited: bcspace on 19th Jul, 2011 - 6:19pm
Since official publication is the definition of doctrine, technically, you are correct because of the Ensign articles. However, my opinion has been just as I stated, that reasons are gambling and time wasting and these are mentioned in the various diatribes against card playing.
What would I counsel the youth under my jurisdiction? I would tell them it's not a problem unless you gamble or it becomes your whole life. Otherwise, I think technically you could also ban such fun and wholesome games like Pit, Mille Bornes, Water Works, etc.
I know it has been said. But I disagree with that sentiment. I think it's pharisaical.
I do not agree with every doctrine of the Church though hopefully my disagreements are minor enough. I will freely admit that something is doctrine according to the Church's standard for doctrine even if I disagree with it and not resort to "It's not doctrine".
My children grew up playing cards and RPG's and so far they are marrying in the temple and serving missions. They still seem to be believing and the adults still seem to be attending Church regularly.
I did not go back and look through the quotes but if there are any that are not published by the Church, you can safely discount them.