Here are the top high THC cannabis strains in 2022. Purple Ghost Candy When it comes to high THC cannabis, Purple Ghost Candy stands out among the best cannabis strains for several reasons. First of all, it's stunning. The leaves have an ornate majesty, but the flowers are the real show-stoppers. Critical Kush is one of the strongest marijuana strains with the highest THC content. It is a powerful Indica strain that takes over your body, providing complete relaxation and significantly calming effects. This strain is the child of Barney's Farm, an Amsterdam-based grower that's responsible for amazing strains such as Liberty Haze and LSD.