Very few studies have been undertaken looking at the use of anti-depressants in adults with learning disabilities and, more recently, with the advent of SSRIs there has not been any study comparing the use of SSRIs with tricyclic drugs in this group. A naturalistic study involving adults with learning disabilities suffering from depressive illness was undertaken in Leicestershire that included 104 treatment episodes with tricyclic/tetracyclic groups of drugs and SSRIs and issues related to efficacy, tolerability, side-effects, polypharmacy and discontinuation rates were looked at. The study, despite its limitations, establishes for the first time that depressive illness in patients with learning disabilities does respond to antidepressant treatment in the same way as that of the general population. The findings suggest that SSRIs are better tolerated and present with fewer serious side effects when compared to tricyclic/tetracyclic groups of drugs. The efficacy of both groups of drugs was found to be very similar. This study also highlights that SSRIs are reasonably safe to use in conjunction with drugs like Lithium and Carbamazepine.