Hashish and marijuana affect a person for at least a week, but can stay in the blood for up to two months.
Hashish and marijuana can induce hallucinations, cause a skewed perception of reality and lead to strong self-overestimation. They also impair orientation and the ability to absorb external impressions.
In Sweden there is a zero limit for narcotic-classified substances in the blood of drivers. Both illegal and legal drugs, as well as certain medications, are regarded as narcotics.
The zero limit for narcotics means that it is prohibited to drive with narcotics in the blood, regardless of whether you are affected or not. Many drugs remain in the blood for a long time – for example, hashish and marijuana can remain in the blood for up to two months – which means that someone trying a drug at a party may be found guilty of driving under the influence of narcotics several weeks later.
The only exception to this rule is for narcotic medications that have been taken according to a doctor's prescription. However, remember that you are not allowed to drive if you are affected by the medication.