Effects of Exercise on Serum Triglycerides and Symptoms of Schizophrenia
There is evidence that increases in serum triglyceride (TG) concentrations are associated with symptom improvement in those receiving antipsychotics.1–4 Accordingly, it can be speculated that any intervention resulting in a reduction in serum TG concentrations could possibly compromise treatment response. In fact, we reported such a case in which a patient showing good response to clozapine relapsed after a 7-week course of a lipid-lowering agent (ie, atorvastatin) that significantly reduced his serum TG concentrations.5 Upon discontinuation of atorvastatin, his serum TG concentrations increased coinciding with a considerable improvement in his symptoms.5
To date, exercise interventions have proven effective in ameliorating cardiometabolic abnormalities in individuals with schizophrenia.6 This is in part due to the fact that exercise has favorable effects on lipid profiles by decreasing serum TG, total cholesterol, and low-density lipoprotein cholesterol (LDL-C) and increasing high-density lipoprotein cholesterol levels.7 In addition, exercise has consistently been an effective intervention for improving the symptoms associated with schizophrenia.6 Although we have cited references previously indicating that reduced serum TG concentrations may lead to poor treatment response, we hypothesize that individuals with schizophrenia who engage in exercise will not only display improvements in their lipid profiles but will also show improvements in their symptoms.
Participants were randomly assigned to either a 12-week moderate-intensity aerobic or resistance exercise program (registered with ClinicalTrials.gov, identifier: NCT01392885). Details on the exercise protocol are explained in our previous report.8 The severity of symptoms was rated by the patient's treating psychiatrist using the Positive and Negative Syndrome Scale (PANSS) before and after the exercise program. Similarly, fasting serum lipid concentrations were determined before and after the exercise program. Wilcoxon signed rank test was used to compare the differences in the variables between baseline and the end of the exercise program. All tests were 2-tailed with the significance level at 0.05 and performed using the Statistical Package for the Social Sciences, version 24. All values are presented in mean (SD).
Nineteen participants (12 men and 7 women) with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of either schizophrenia (n = 8) or schizoaffective disorder (n = 11) signed the informed consent and completed the 12-week exercise program. The mean age was 31.9 (6.8) years, and the mean duration of illness was 10.5 (5.6) years. All participants were treated with second-generation antipsychotics (ie, clozapine, olanzapine, quetiapine, risperidone, paliperidone, aripiprazole, ziprasidone, and sulpiride), and some were augmented with first-generation antipsychotics (ie, haloperidol, loxapine, and flupenthixol). The dose equivalents were not significantly different from baseline to the end of the exercise program (P = 0.682).
A trend reduction from baseline to the end of the exercise program was noted in serum TG concentrations (1.8 [1.6] to 1.5 [1.0] mmol/L, P = 0.075), but no significant changes were noted in the concentrations of other serum lipids. Nonetheless, all serum lipid concentrations showed favorable changes (TG, −16.7%; total cholesterol, −4.9%; LDL-C, −4.5%; high-density lipoprotein cholesterol, +8.3%) after the exercise program. With respect to symptoms, significant reductions in total and subscale PANSS scores were noted from baseline to the end of the exercise program as follows: total score (24.1% reduction from a baseline of 95.5 [13.5], P < 0.001), positive symptoms subscale score (28.2% reduction from a baseline of 25.8 [4.8], P = 0.001), negative symptoms subscale score (18.6% reduction from a baseline of 21.0 [4.5], P = 0.007), and general psychopathology subscale score (24.2% reduction from a baseline of 48.7 [8.2], P = 0.001).