Driving fitness in clinically stable outpatients with chronic schizophrenia

Driving motorized vehicles is an integral part of individual mobility and a key parameter for employment and social integration. This naturalistic, cross-sectional study investigated the associations between driving fitness, residual symptomatology, olanzapine equivalent, and extrapyramidal symptoms (EPS) in long term stable outpatients with schizophrenia.

Beside sociodemographic data, and driving habits, residual symptoms, and EPS were assessed using the Positive and Negative Syndrome Scale (PANSS), and the Modified Simpson Angus Scale (MSAS). PANSS symptoms were analyzed using the Wallwork/Fortgang five-factor model. MSAS cut-off scores ≥3 were defined as positive for EPS. Driving skills were assessed using the Vienna Test System and an expert evaluation.

50 patients were included into the study. Mean PANSS total scores indicated mild residual symptomatology and EPS were not present in 48% of study participants. 44% passed the driving fitness assessment and were considered as competent to drive, 20% were judged to be partially competent and 36% to be incompetent to drive. With the exception of disorganization (r = -0·287, p = 0·048) residual symptoms of schizophrenia did not correlate with driving fitness. However, moderate negative correlations were detected between driving fitness and the severity of EPS (r = -0·554, p = 0·000), age (r = -0·413, p = 0·003) as well as olanzapine equivalent doses (r = -0·432, p = 0·002). These results were not corrected for multiple comparison.

The present findings indicate that up to two thirds of clinically stable outpatients with chronic schizophrenia may be (partially) competent to drive. Both the presence of EPS as well as the dosage of antipsychotic medication seem to be of particular relevance in this regard.