Is a mild intellectual disability related to more severe positive and negative symptoms in patients with a psychotic disorder?

Abstract

Abstract thesis Having a mild intellectual disability (MID) is related to a higher chance of developing mental health problems, like a psychotic disorder (Tsakanikos & McCarthy, 2014). It is thought that positive and negative symptoms of psychotic disorders are different in patients with a comorbid MID, but how it is different exactly is not well understood. Therefore, the aim of this study was compare the severity of positive and negative symptoms in patients with a psychotic disorder and MID to patients with only a psychotic disorder. It is hypothesized that the group with comorbid MID will have more severe positive and negative symptoms. This study includes 58 participants (Mean age (SD) = 39.07 (11.29)) from the UP’s study of the Erasmus Medical Centre that are diagnosed with a psychotic disorder. The participants are divided into a group with MID and without MID based on the Dutch Screener for Intelligence and mental disability (SCIL) and level of education. The symptoms are scored with the Positive and Negative Symptoms Scale (PANSS). The differences in PANSS scores are tested with Mann-Whitney U tests. Correlation analyses have also been done between the SCIL and positive and negative symptoms. No relation between MID and severity of symptoms has been found. It is possible that MID only increases the severity of symptoms when significant impairments from the MID are present. More research is needed that study how psychotic symptoms express themselves in patients with MID, so they can be detected better. This will improve prognosis and treatment.