I haven't smoked spice (synthetic cannabinoids) for 4months but i feel mentally strange and depressed. what is known about th effects of spice?

"spice": Recent article on synthetic cannabinoids listed hypertension, rapid heart rate, nausea & vomiting, agitation, anxiety, paranoia, seizures, & suicidal ideation as reported side effects/reactions. See your fp or a detox specialist for help.

A lot from cannabis: While not a lot is known about the synthetics themselves, we know a lot about chronic marijuana use. There have been at least 3 large studies in 3 different countries that showed a dose-dependent effect of marijuana on schizophrenia. These studies showed that the earlier you start using and the more you use, the greater the chance you have of schizophrenia. Cannabis is a hallucinogen.

Not much: Spice is still legal in the United States, but has been banned in most of europe and parts of asia and south america. I am not familiar with spice, but canabinoids in general can stay in your system for weeks. One of the effects of canabinoids is apathy. Though it may not even be related, some abused substances can change your brain induce persistent changes in your brain chemistry. See your docto.