I was just editing a paper on schizophrenia and noticed that one of the symptoms of the disease is called asociality. Being asocial (lacking a strong motivation to engage in social interaction or preferring solitary activities) is not the same as being antisocial (active dislike or antagonism toward other people or the general social order).
One antonym for asocial is gregarious. To turn that into a pejorative, you can prefix hyper- or ultra-.
That'll give you:
hypersocial and hypergregarious
[M-W 3rd Unabridged says: "Main Entry: hyper-
Etymology:alteration (influenced by Latin hyper-) of Middle English iper-, from Late Latin hyper-, from Latin, from Greek, from hyper (more at OVER)
1 : over : above : beyond : SUPER- hyperbarbarous, hyperemphasis
2 : overmuch : excessively : EXTRA- hypercritical, hypersensitive
3 a : excessive in extent or quality hyperesthesia, hyperemesis,]
as well as
ultrasocial and ultragregarious
[M-W 3rd Unabridged says: "Main Entry: ultra-
Etymology: Latin, from ultra beyond (adverb & preposition), from abl. singular feminine of (assumed) ulter situated beyond (more at ULTERIOR)
3 : beyond what is common, ordinary, natural, right, proper, or moderate : excessively : exceedingly : HYPER- ultracomplex, ultracritical, ultraformal, ultramodern]
The problem with ultrasocial, however, is that Jonathan Heidt and others have approbatorily appropriated the term to describe human and animal ("social insects and colonial invertebrates") societies, because most people are social, not asocial or antisocial.
(#)Hypersocial and ultra-gregarious are associated with a neurological problem called Williams Syndrome# (#: see next paragraph), so using those terms is probably politically incorrect because it implies that the person they're used to describe is "crazy".
(#)"People with Williams Syndrome (caused by deletion of a certain region on chromosome 7) are hypersocial, ultra-gregarious; as children they fail to show a normal fear of adult strangers. WSers are cognitively impaired on most dimensions, but their verbal abilities are spared or even exaggerated; they often speak early, with complex sentences and large vocabulary, and excellent verbal recall, even if they can never learn to do basic arithmetic."
That leaves only hyper-gregarious, which is used in a medical book to describe one clinical symptom seen in some alcoholics.
Another possibility is to coin words like sociorrhea, sociorrheic, gregariorrhea, and gregariorrheic, using diarrhea and logorrhea as models, by adding the suffix -rrhea. Those two conditions are considered pretty obnoxious, I'd say, and are never used with positive connotations.
A little bit of imagination will take you a long way in the world of neologisms.