A debilitating chronic illness that affects 20,000 New Zealanders is likely to be causing large numbers of school absenteeism in teenagers.

Wellington psychologist Rose Silvester, whose son has long-standing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, said the complex disease severely impacts the development of academic, cognitive and social skills in young people. It has no cure.

There is currently no data on New Zealand students with ME/CFS but a newstudy in Australia shows students with ME/CFS missed an average of 40 per cent of classes over a term, or at least two days per week.

Their healthy peers by comparison,