Mar­i­juana: The good, bad and un­known

Re­port sheds light on health ef­fects of drug

Hawaii Tribune Herald - - FRONT PAGE - By MAL­COLM RITTER

NEW YORK — It can al­most cer­tainly ease chronic pain and might help some peo­ple sleep, but it may also raise the risk of get­ting schizophre­nia and trig­ger heart at­tacks.

Those are among the con­clu­sions about mar­i­juana reached by a fed­eral ad­vi­sory panel in a re­port re­leased Thurs­day.

The ex­perts also called for a na­tional ef­fort to learn more about mar­i­juana and its chem­i­cal cousins, in­clud­ing sim­i­larly act­ing com­pounds called cannabi­noids.

The cur­rent lack of sci­en­tific in­for­ma­tion “poses a pub­lic health risk,” said the re­port, from the Na­tional Academies of Sciences, En­gi­neer­ing and Medicine. Pa­tients, health care pro­fes­sion­als and pol­icy makers need more ev­i­dence to make sound de­ci­sions, it said.

For mar­i­juana users or those con­sid­er­ing it, “there’s very lit­tle to guide them” on amounts and health risks, said Dr. Marie McCormick of the Har­vard School of Pub­lic Health, who headed the com­mit­tee.

Sev­eral fac­tors have lim­ited re­search. While the fed­eral gov­ern­ment has ap­proved some medicines con­tain­ing in­gre­di­ents found in mar­i­juana, it still clas­si­fies mar­i­juana as il­le­gal and im­poses re­stric­tions on re­search.

So sci­en­tists have to jump through bu­reau­cratic hoops that some find daunt­ing, the re­port said.

A fed­eral fo­cus on pay­ing for stud­ies of po­ten­tial harms has also ham­pered re­search into pos­si­ble health ben­e­fits, the re­port said. The range of mar­i­juana prod­ucts avail­able for study has also been re­stricted, although the gov­ern­ment is ex­pand­ing the num­ber of ap­proved sup­pli­ers.

Twenty-eight states and the Dis­trict of Columbia have le­gal­ized mar­i­juana for a va­ri­ety of med­i­cal uses, and eight of those states plus the dis­trict have also le­gal­ized it for recre­ational use.

The re­port lists nearly 100 con­clu­sions about mar­i­juana and its sim­i­larly act­ing chem­i­cal cousins, draw­ing on stud­ies pub­lished since 1999.

Com­mit­tee mem­bers cau­tioned that most con­clu­sions are based on sta­tis­ti­cal links be­tween use and health, rather than di­rect demon­stra­tions of cause and ef­fect.

The re­view found strong ev­i­dence that mar­i­juana can treat chronic pain in adults and that sim­i­lar com­pounds ease nau­sea from chemo­ther­apy, with vary­ing de­grees of ev­i­dence for treat­ing mus­cle stiff­ness and spasms in mul­ti­ple sclero­sis.

Lim­ited ev­i­dence says mar­i­juana or the other com­pounds can boost ap­petite in peo­ple with HIV or AIDS, and ease symp­toms of post-trau­matic stress dis­or­der, the re­port con­cluded. But it said there’s not enough re­search to say whether they’re ef­fec­tive for treat­ing can­cers, ir­ri­ta­ble bowel syn­drome, epilepsy, or cer­tain symp­toms of Parkin­son’s disease, or help­ing peo­ple beat ad­dic­tions.

There may be more ev­i­dence soon: a study in Colorado is in­ves­ti­gat­ing the use of mar­i­juana to treat PTSD in vet­er­ans.

Turn­ing to po­ten­tial harms, the com­mit­tee con­cluded:

• Strong ev­i­dence links mar­i­juana use to the risk of de­vel­op­ing schizophre­nia and other causes of psy­chosis, with the high­est risk among the most fre­quent users.

• Some work sug­gests a small in­creased risk for de­vel­op­ing de­pres­sive dis­or­ders, but there’s no ev­i­dence ei­ther way on whether it af­fects the course or symp­toms of such dis­or­ders, or the risk of de­vel­op­ing post-trau­matic stress dis­or­der.

• There’s a strong in­di­ca­tion that us­ing mar­i­juana be­fore driv­ing in­creases the risk of a traf­fic ac­ci­dent, but no clear link to work­place ac­ci­dents or in­juries, or death from a mar­i­juana over­dose.

• There’s lim­ited ev­i­dence for the idea that it hurts school achieve­ment, raises unem­ploy­ment rates or harms so­cial func­tion­ing.

• For preg­nant women who smoke pot, there’s a strong in­di­ca­tion of re­duced birth­weight but only weak ev­i­dence of any ef­fect on preg­nancy com­pli­ca­tions for the mother, or an in­fant’s need for ad­mis­sion to in­ten­sive care. There’s not enough ev­i­dence to show whether it af­fects the child later, like sud­den in­fant death syn­drome or sub­stance use.

• Some ev­i­dence sug­gests there’s no link to lung can­cer in mar­i­juana smok­ers. But there’s no ev­i­dence, or in­suf­fi­cient ev­i­dence, to sup­port or re­but any link to de­vel­op­ing can­cers of the prostate, cervix, blad­der, or esoph­a­gus.

• Sub­stan­tial ev­i­dence links pot smoking to worse res­pi­ra­tory symp­toms and more fre­quent episodes of chronic bron­chi­tis.

• There’s a weak sug­ges­tion that smoking mar­i­juana can trig­ger a heart at­tack, es­pe­cially for peo­ple at high risk of heart disease. But there’s no ev­i­dence ei­ther way on whether chronic use af­fects a per­son’s risk of a heart at­tack.

• Some ev­i­dence sug­gests a link be­tween us­ing mar­i­juana and de­vel­op­ing a de­pen­dence on or abuse of other sub­stances, in­clud­ing al­co­hol, to­bacco and il­licit drugs.

Associated Press

Mar­i­juana grows at a med­i­cal mar­i­juana cul­ti­va­tion cen­ter in 2015 in Al­bion, Ill.

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