**4.1 Overall performance**

It was found that the children with dyslexia had trouble both with writing and with reading, whereas children with ADHD had trouble mainly with writing and showed little evidence of impaired reading. Our finding about dyslexics seems to accord fairly well with previous findings. On the other hand, our finding about ADHD patients should be treated with caution, given the frequent co-occurrence of ADHD with language-related learning problems. Though ADHD has been reported to co-occur with problems in writing more often than with problems with reading in accordance with our results, several independent studies have reported that ADHD patients have problems not just with writing, but also with both reading and writing when they have any language-related problems (Rucklidge and Tannock 2002; Willcutt et al. 2005). If a further study involving a larger number of ADHD patients confirms our finding, that will constitute new information about ADHD.

As was particularly obvious in the overall performance of children with ADHD and with dyslexia at Grade 3 in Fig. 3, there was not always a difference in performance between ADHD patients and dyslexics, possibly because of the small sample size. At the moment, overall performance does not differentiate ADHD patients and dyslexics as reliably as orthographic performance and phonological performance, to be discussed below.
