Background
The exact relationship between aggression and epilepsy is a matter of ongoing debate.

Aims
Identify whether there is an association between epilepsy and problem behaviour among adults with intellectual disabilities by carrying out a systematic review of published data.

Method
We searched for relevant articles using five relevant databases and hand searched six relevant journals, reviews and papers for cross referencing. Two authors have independently screened titles, abstracts and full articles using a standardised eligibility checklist. The data were extracted by two authors who also completed Cochrane risk of bias tool and SIGN-50 checklist. Several meta-analyses were carried out.

Results
Thirty-four articles from 32 studies provided data on 14,168 adults with intellectual disabilities. Of the 19 controlled studies, 13 did not show any statistically significant intergroup difference in the rate of problem behaviour. A meta-analysis showed no statistically significant intergroup difference when data from 16 studies were amalgamated, but when data from nine studies were pooled after a sensitivity analysis, epilepsy group showed a significantly higher rate of overall problem behaviour (effect size: 0.16). Aggression and self-injurious behaviour both showed a statistically significant higher rate in the epilepsy group with a very small effect size (0.16 and 0.28 respectively). No significant intergroup difference was observed in the rate of stereotypy.

Conclusions
The included studies assessed only inter-ictal behaviour. However, problem behaviour may be manifested during pre-ictal, ictal and post-ictal phase which needs to be addressed by exploring factors leading to problem behaviours in adults with intellectual disabilities.