Is insulting friends and the like, which the mind does uncontrollably, considered a form of waswasah (insinuating thoughts), and what is its cure?

The determination of whether a certain behavior is a result of obsessive whispers (waswasa) or insanity is referred to a psychiatrist or a trustworthy practitioner of legitimate Islamic exorcism (ruqya shar'iyya). Abusing a Muslim is فسوق (disobedience/impiety), unless the person has completely lost their mind, in which case there is no sin upon them.