Neurological Soft Signs in First Episode Psychosis among Psychiatric Hospital Patients and its Relationship with Dimensions of Psychopathology: A Comparative Study

Abstract

Background: Neurological soft signs (NSS), as subtle, nonlocalising neurological abnormalities, are considered as the potential markers of psychosis. However, comparative studies of antipsychotic-naïve patients with first-episode psychosis (FEP) and first degree relatives (FDRs) are uncommon. We compared the prevalence and pattern of NSS in FEPs, their healthy FDRs and a healthy non-relatives’ control group (HC), highlighted the relationship between NSS and psychopathology and proposed cut-off scores for prevalence studies. Materials and Methods: Two hundred and two participants per group were recruited. The FEPs were consecutive attendees; FDRs were accompanying caregivers; while the HC were from hospital staff. The Brief Psychiatric Rating Scale and the Neurological Evaluation Scale were used to assess psychopathology dimensions and NSS, respectively. Results: Using an item score of two (‘substantial impairment’), the prevalence of at least one NSS was: 91.5% (95% confidence interval [CI]: 86.7%–94.9%), 16.8% (95% CI: 11.8%–22.7%) and 6.5% (95% CI: 3.5%–10.9%), respectively, for FEP, FDRs and HC. FEPs were impaired in a broad range of signs. The noteworthy relationships were as follows: (i) a significant correlation between the negative symptoms’ dimension versus number of NSS (r = 0.4), and NSS total score (r = 0.3), (ii) the anxiety/depression dimension correlated negatively with number of NSS (r = −0.3) and (iii) NSS cut across psychosis categories. We propose a cut-off score of ≥ 4 for the number of signs signifying probable impairment. Conclusion: The findings indicate that, subject to further studies, NSS could be regarded as a broader phenotype of neurologic dysfunction associated with psychosis proness.