The cannabis plant makes most cannabinoids, like THC, CBD, and CBC, out of CBG-A. CBGV-A appears in the plant much more rarely, and forms similar cannabinoids, except they only have 3 carbon tails (c3), instead of the more common 5 carbon tail (c5). These 3 carbon tailed cannabinoids are referred to as ‘varins’, such that the c3 version of THC (THC-c5) is named Tetrahydrocannabivarin (THC-c3).
Being closely related to the c5 version, the c3 versions have very similar properties along with other unique qualities. For instance, THCV is more strongly psychoactive than THC, but only has about half the duration of THC. THCV is also a protagonist of THC, modifying the effects of THC. The energetic effect of THCV is more pronounced and stronger.
THCV has been found to reduce or even block panic attacks and, as a result, can be highly effective in the management of PTSD and other mental disorders involving anxiety or stress. http://steephilllab.com/thcv-the-sports-car-of-cannabinoids/