A new large scale study of cannabis use has found that those who consume the drug before the age of 17 are two thirds less likely to complete secondary school than those who never used the drug.

The research, which was published in the journal Lancet Psychiatry, revealed that those who use cannabis daily during adolescence are seven times more likely to attempt suicide.

The study was carried out by a team of Australian and New Zealand researchers.

It involved an analysis of data from more than 3,700 cannabis using participants in three large long-running pre-existing studies.

It found strong associations between the use of cannabis during adolescence and what happened to the participants in early adulthood.

It also discovered the risks faced increased relative to the amount of cannabis consumed, with daily users facing the strongest negative effects.

Those using the drug daily face an 18 times greater chance of being dependent on it, for example, and are eight times more likely to use other illegal drugs later in life.

The study found that those who use cannabis before the age of 17 are 60% less likely to finish school or obtain a degree. 

The authors said the findings provide strong evidence that the prevention or delay of cannabis use is likely to have broad health and social benefits.