Increased sense of humor
Increased sense of humor can be described as a general enhancement in the intensity of one's response to humorous or amusing stimuli. During this state, one's sensitivity to finding things funny can be noticeably amplified, this is often to the point that one can begin uncontrollably laughing at trivial things without any discernible reason or apparent cause.
In group settings, the experience of witnessing someone laughing in enjoyment for no apparent reason can itself become a contagious trigger which induces semi-uncontrollable laughter within the people around them. In extreme cases, this can often form a lengthy feedback loop in which people begins to laugh hysterically at the absurdity of not being able to stop laughing.
Compounds within our psychoactive substance index which may cause this effect include: