Prevalence, Predictors and Morphological Patterns of Acanthosis Nigricans Between Obese Non-diabetic Patients on Second Generation Antipsychotics Versus Non-obese Insulin Dependent Diabetes mellitus: A Nested Case-Control Study

INTRODUCTION: There is no study in literature for analyzing acanthosis nigricans (AN) in psychotropic induced obesity or hypercholesterolemia. AIM: To assess the prevalence and explore the predictors and morphological patterns in AN in patients on antipsychotics induced hypercholesterolemia versus those with diabetes mellitus. MATERIALS AND METHODS: 491 schizophrenia patients on second generation antipsychotics were screened. 26 out of 491 patients have AN and cholesterol > 200mg/dl but non-diabetic. We used Mann Whitney U test, Pearson's χ2 test, Fischer Exact and Spearman's correlation coefficient. RESULTS: In the group of antipsychotics induced hypercholesterolemia having developed AN in 5.29% (26 out of 491) of individuals, we observed significance of Burke's knuckle (p < 0.001), knee (p = 0.002), elbow (p = 0.042) compared to patients without hypercholesterolemia. Interestingly Burke's neck severity (p < 0.001), neck texture (p = 0.001) and axilla (p = 0.007) index also showed marked differences on Mann Whitney U test and Wilcoxson W test. On Spearman's correlation coefficient antipsychotics induced hypercholesterolemia was found to affect most positively and significantly as the emergence of AN specifically for neck texture (ρ = 0.413, p = 0.003) compared to other bodily regions. CONCLUSION: About 5.29% prevalence of AN in the group having obesity secondary to psychotropic drugs which was significantly less than what even non-obese, insulin dependent diabetic patients who almost had 13.55% prevalence, close to three times. This suggests that diabetes is strongly linked with occurrence of AN lesions and might reflect the continuity in the paradigm of metabolic syndrome as its definitive predictor of severity while obesity is the initiation of phase shift in the process.