great idea but I dont think it would be good,

A because this is a mental health website who's rules are all posts are supposed to be supportive...how is clicking dislike going to make other members feel especially if that member has a mental problem where one of their symptoms is low self esteem (example their self talk may reflect...see that that person doesnt like me I was right in not liking me too) Depression (their internal talk may reflect something like what did I do wrong, I cant even post so everyone likes me and my posts why bother I might as well....and end up in suicidal modes) or even a member with a mental disorder where paranoia is a symptom (omg that person clicked dislike, are they out to get me, are they stalking me are they going to harm me....)

no I dont think a dislike button is needed on a mental health support oriented website is needed...

B the standard here is if you dont like something or someone to either not post in that thread or place the poster on ignore so you dont have to deal with posts you have a problem with..

C. members already use the thanks button and hugs and pming to let each other know they like the post, there is also smilies members can place in their posts. the smilies are to the right of the posting box while you are writing your post.