However, while some drugs, including cannabis and opioids, appear to have a dosedependent impairing effect, others such as amphetamines do not.
Cé go bhfuil an chuma ar an scéal go bhfuil éifeacht lagaithe ag brath ar dháileog ag roinnt drugaí, lena n-áirítear cannabas agus substaintí óipiam, ní hé sin an cás le roinnt eile ar nós amfataimíní.