By Emma Young
Aerobic exercise – any activity that gets your heart pumping harder – improves mood, anxiety and memory. It can help people with major depressive disorder, bipolar disorder and anxiety disorder. Now there’s evidence, from a randomised controlled trial published in Frontiers in Psychiatry, that a programme of regular aerobic exercise also reduces psychopathology in people diagnosed with schizophrenia. And it seems to have a particular impact on so-called “negative” symptoms, such as apathy and loss of emotional feeling, which are not improved by standard drug treatments.
“[W]hile antipsychotics [drug treatments] are essential in treating schizophrenia, interventions other than antipsychotic treatment…may be needed to achieve better outcomes,” write the authors of the new study, led by Peng-Wei Wang at Kaohsiung Medical University Hospital in Taiwan.
The researchers recruited 62 patients, all of whom had received a diagnosis of schizophrenia at least a year ago, and whose antipsychotic medication dosage had been stable for at least three months. These participants were randomly allocated into either an aerobic exercise group (30 minutes of “vigorous” aerobic exercise, taking into account each participant’s maximum heart rate) or a control group who performed stretching exercises (25 minutes of flexibility, toning and balance exercises), with a goal of five sessions a week, for 12 weeks. Not all participants managed to stick to the minimum requirement of three sessions per week for the full three months. But 24 in the exercise group and 22 in the control group did complete the study. (There were no significant differences in gender make-up, age of onset of schizophrenia, or mean dosage of antipsychotics between the two groups.)
A psychiatrist who was blind to the group allocations used a standard schizophrenia symptom evaluation scale to interview and evaluate all the participants at the start of the study; at the end of the 12 week intervention; and again, three months on. The control group showed no improvements in positive (e.g. hallucinations and delusions) or negative symptoms, or general psychopathology, during the intervention or the follow-up period. But for the aerobic exercise group, it was a different story.
Over the 12-week intervention, their overall psychopathology and level of negative and positive symptoms decreased. Three months later, these improvements had been maintained (and, in the case of negative symptoms, actually continued to improve). Also, the more severe their negative symptoms and general psychopathology at the start of the study, the bigger their improvements by the end.
“These results imply that [aerobic exercise] could be a good non-pharmacotherapeutic intervention for antipsychotic-treated patients with schizophrenia,” the researchers conclude.
There are various possible explanations for the effects. Vigorous exercise can boost levels of the neurotransmitter glutamate (other work has found that enhancing glutamate function can improve negative symptoms of schizophrenia); increase levels of brain-derived neurotrophic factor (which is involved in repairing damaged brain cells and triggering the growth of new ones; low levels of BDNF are associated with symptoms of schizophrenia); and also help regulate the hypothalamic-pituitary-adrenal (HPA) axis – the stress response system. “HPA dysfunction is an important characteristic in schizophrenia,” the authors note.
But is a one-off 12-week programme really enough to produce lasting – and even escalating – improvements?
The researchers did not collect data on how much exercise the aerobic group did in the three months between the end of the 12-week intervention and the final assessment. If the participants continued to exercise, this may have accounted for the ongoing improvements. Future research will have to explore this. But if an exercise programme does have to be maintained, given all the manifold benefits, surely that’s no bad thing.