The two are linked only in the very broadest sense, in that both of them are things that happened in the same American society and so currents in the Zeitgeist that affected one affected the other. Generally the rise of psychotherapies such as CBT or Rogerian person-centered therapy come from the post-World War II movement to draft psychologists to help World War II vets with mental health problems. Before World War II, psychologists had been 'ivory tower' theorists and researchers, broadly speaking, rather than practitioners. With that background, and coming from some quite different philosophical perspectives to the Freudian psychoanalysis popular within psychiatry at that time period (psychiatry is a different discipline to psychology - psychiatrists being medical doctors specialising in mental health), the clinical psychologists of the late 1940s and 1950s developed a variety of approaches competing against each other.

Some of the approaches to therapy of the 1950s and 1960s, broadly speaking, were aligned with the 'humanistic psychology' movement/approach/metatheory/ism of Abraham Maslow and Carl Rogers and others. Others were more aligned with the 'behaviourist' movement associated with, e.g., B.F. Skinner focused on the possibilities of operant or classical conditioning. CBT is an odd and somewhat awkward melding, philosophically, between behaviourist techniques and Aaron T. Beck's 'cognitive therapy', which I think was fairly straightforwardly in the 'humanistic psychology' movement. The humanistic psychology movement also had an either implicit or explicit critique of the quite buttoned-down/repressed American society of the time, and members of the movement flirted with, e.g., the idea of using psychedelic drugs to open minds in the 1960s, and were approving of the hippies as people trying to escape the repression endemic in mainstream American society in the era.

This is probably where the (fairly tenuous) link between disco and psychotherapy would come in.

While your wiki-ing suggests early disco is from the 1960s...this is probably better seen as the start of discotheques, nightclubs where people danced to records spun by a DJ; it was only really in that era that speaker and vinyl/turntable technology advanced to a state where the aural experience of the discotheque was comparable to seeing a live band.

Disco as a dance-oriented genre formed in such discotheques dates more from the early 1970s, formed out of elements of 1960s soul - especially the sweeter soul put out by Motown and then the whole Philadelphia soul phenomenon associated with the producers Gamble and Huff - and adding in a bit of 1970s African-influenced funk (you can get a flavour of the sounds that came together to create disco on this compilation released on Soul Jazz Records).

Generally speaking, disco music, to the extent it has about-ness, is about dancing. Dancing obviously occurs worldwide in a bunch of different environments, and not just in American discotheques in the early 1970s; but the New York discotheque scene that birthed disco was noticeably not-particularly-white - often either Black or Latino - and noticeably not-particularly-straight. This does correspond, broadly speaking, with a movement to de-medicalise homosexuality, which had previously been considered by psychiatrists, according to their Diagnostic and Statistical Manual, at least, as a mental illness that one could claim treatment for on their insurance; it was in the 1970s that the American Psychiatric Association finally removed homosexuality from the DSM.

Additionally, the ways of thinking about society that the humanistic psychologists had in the 1950s and 1960s, also floated around in pop music in the 1960s and 1970s (but the link is more clearly present in the hippie music of the 1960s, rather than the disco music of the 1970s and especially the disco music of the late 1970s once it became a commercial juggernaut). Both the hippie music of the 1960s and the humanistic psychologists were concerned with the establishment of the authentic self, and the way that society could push back against the authentic self. It's probably fair to say that disco was a bit warier of the authentic self, with people choosing to lose their selves in dance. Disco music generally avoids discussion of the authentic self, preferring to focus on community (e.g., 'We Are Family'), survival ('I Will Survive') and, well, dancing (...this is a million songs).

But it's nonetheless somewhat shaped by other music that is more concerned with the authentic self - in particular the funk of the late 1960s and early 1970s, with funk playing a role in the creation of authentic selves that were somewhat equivalent to what the hippies were doing but focused on the lives and concerns of Black Americans. And as unabashed pop music, the disco of the 1970s couldn't help but be influenced by the pop trends of the 1970s, which also included music that was more clearly focused on the authentic self (hippies continued to make rock music in the 1970s, of course) (Jessica Grogan's book Encountering America: Humanistic Psychology, Sixties Culture, and the Shaping Of The Modern Self is a fairly accessible book on this topic matter more generally).

So that's the pretty tenuous link there.

But disco was, of course, mostly about dancing. And while dancing can certainly be therapeutic...it's not actually therapy.