This study was based on the treatment at an outpatient clinic of 40 – 50 daily users with a habit of from 6 months to 25 years.  The researchers observed users have a special way of thinking, or pattern of thought.  This is more visible in long term use and the use of cannabis more often than every six weeks for two years will increase the effect on cognitive function and make serious dysfunction worse. The study showed negative outcomes for verbal ability, logical – analytic ability, psychomobility, memory, analytic-synthetic ability and psychospatial ability.  The chronic effect of cannabis was seen to be a loss of quality of these abilities.  It is also suggested that this specific ‘cannabis pattern’ is a result of prefrontal lobe dysfunction in the brain.