Kush, a mixture of chemical substances with similar effects to cannabis, has been prevalent in the country for several years.
In an address to the nation, Bio said "it is my solemn duty as president... to declare a national emergency on drug abuse."
"Our country is currently facing an existential threat due to the devastating impact of drugs and drug addiction, in particular the devastating synthetic drug kush," he added.
A task force including government agencies and non-governmental organizations would be responsible for prevention, treatment, social services support, law enforcement and community engagement.
Bio said his government was working to take down drug trafficking networks.
Authorities seized two containers in the capital of Freetown that were filled with kush, police commissioner Joseph Lahai said on Thursday, adding, seven suspects were taken into custody.
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