It depends on how often and how much cannabis a person smokes and the potency (strength) of the cannabis.
In general, the less cannabis that’s smoked, and the less often it’s smoked, the quicker it leaves the body.
THC, the active chemical in cannabis, is stored in the fat cells and therefore takes longer to fully clear the body than any other common drug. The stronger the strain of cannabis, the more THC it contains.
Drug testing equipment, as used by the police, works by measuring the amount of THC in a urine sample.
A review of data compiled by the US National Drug Court Institute estimated that:
Long-term use of cannabis can make you depressed and make you less motivated.