severe social withdrawal , called hikikomori , has drawn increased public attention , especially in japan .
however , it has developed into an international issue across several cultures [ 1 , 2 ] .
hikikomori is characterized by severe social withdrawal and isolation for more than six months that is not due to obvious psychosis , mental retardation , or other mental disorders ; however , there are likely various psychiatric implications related to hikikomori , such as social anxiety disorder .
it is extremely difficult to make a concrete evaluation of hikikomori , as well as to provide suitable treatment .
treatment resistant hikikomori has been a severe problem in the clinical field because pharmacotherapy may only produce a partial effect .  
although the efficacy remains controversial , physical exercise is considered to be beneficial for alternative treatment of psychiatric illness , especially major depression .
its application to other mental illnesses is worthwhile , given that eligibility for exercise therapy is sufficiently evaluated . here ,
we report the case of a young male inpatient with hikikomori who responded to regular continuous jogging exercise intervention for three months .
hemodynamic alteration as a function of the exercise intervention was assessed by near infrared spectroscopy ( nirs ) .
the protocol was approved by the ethics committee of jichi medical university . a 20 year old male presented with severe social withdrawal identified as hikikomori since he was a junior high school student due to severe social anxiety with extreme avoidant tendencies .
he was persuaded by his family to see a doctor and was voluntarily hospitalized to evaluate the diagnosis and possible treatment .
as his history did not reveal communication difficulties or adhesive features , autistic spectrum disorder was considered an unlikely diagnosis . regarding intelligence
, he scored 88 on the viq , 50 on the piq , and 66 on the fiq components of the wechsler adult intelligence scale , third edition .
he showed depressive and anxiety symptoms that were likely due to social isolation as a function of hikikomori , scoring 46 on the center for epidemiologic studies depression scale .
taken together , the patient was diagnosed with social anxiety disorder with mild mental retardation according to the criteria of dsm-5 ( diagnostic and statistical manual of mental disorder , fifth edition ) , showing severe hikikomori for around four years . on admission , 25-mg daily sertraline was initiated and increased to 50 mg after a week .
although sertraline was effective for depressive - anxiety symptoms , the efficacy was partially limited , and social anxiety and his lack of self - confidence remained .
one and one half months after admission , we introduced jogging around the hospital three times a week , accompanied by the resident , as a secondary therapy .
as physical complications were carefully excluded by the examination , the jogging schedule was assigned to the patient as an exercise treatment three times a week . after acquiring his consent ,
the patient was instructed to perform about 30 minutes of jogging ( a distance of approximately 1000 meters ) at a reasonable speed in the athletic grounds of the university . in order to assess daily activity , including calorie consumption and sleep condition , waist actigraphy ( fs750 , estera co. , saitama , japan ) was attached to the patient .
daily average steps , daily calories burned , and daily calories including basal metabolism were 7286  2625 , 402.7  113.1 , and 2232  126 , respectively .   through the three month intervention with jogging therapy , social anxiety symptoms gradually reduced and self - confidence improved . in addition , insomnia and psychomotor inhibition improved .
we evaluated cerebral hemodynamic alteration as a function of the jogging intervention by nirs examination using a verbal fluency task ( vft ) . in terms of hemodynamics , relative oxygenated hemoglobin ( oxy - hb ) , deoxygenated hemoglobin ( deoxy - hb ) , and total hemoglobin ( total - hb )
were measured using an etg-4000 52-channel optical topography system ( hitachi medical corporation , tokyo , japan ) , as described in a previous study .
we calculated the frontal grand average waveform of the frontal region of interest ( roi ) and the bilateral temporal grand average waveforms from the bilateral temporal roi ( fig .
the integral values during the vft from the oxy - hb waveforms in both the frontal and the bilateral temporal rois were used as markers of cerebral activity .
although the integral value in the frontal roi was not altered , the integral value in the bilateral temporal roi increased significantly after the continuous jogging therapy ( fig .
our patient with social anxiety disorder was consistently treated with selective serotonin reuptake inhibitor pharmacotherapy .
although the administration of sertraline may have reduced social anxiety , this would have been limited to a partial effect because psychomotor inhibition did not improve substantially after the effect of sertraline emerged .  
it has been broadly accepted that early intervention for mental illness among younger people , such as those with at - risk mental states , is a therapeutic approach resulting in good long - term prognosis .
however , excessively early interventions may carry a risk of yielding false positives , especially when prescribing psychotropic agents .
exercise therapy is a possible non pharmacological option for young patients that has shown promising results .  
although exercise therapy has mostly been applied as a treatment for major depressive disorder , among various psychiatric disorders , its clinical efficacy has remained under debate . in spite of
the exact mechanisms how exercise affects the brain , including brain - derived neurotrophic factor ( bdnf ) , vascular endothelial growth factor ( vegf ) , insulin like growth factor ( igf-1 ) and the gene vgf ( nerve growth factor inducible ) , are not fully understood , properly designed studies elucidated that exercise training can be as effective as antidepressive medications .
this case likely responded well to exercise therapy because of the management of the duration and vigor of exercise , as comfortable and reasonable exercise expectations were maintained .
in addition , increased hemodynamics in the bilateral temporal region were prominent as a result of the exercise intervention . altered hemodynamics measured by nirs using a vft may represent a neurophysiological index to distinguish and evaluate depressive states . although noda et al . suggested that oxy - hb changes during vft in the right dorsolateral prefrontal cortex may be a state dependent marker of major depression , this case did not exhibit hemispheric differences in hemodynamics , and thus we provided averaged waveforms for the bilateral temporal regions .
it has been speculated that hemodynamic changes observed in the frontal region are likely a trait - dependent marker , whereas those observed in the temporal region are a state dependent marker . taken together , measuring hemodynamics using nirs was useful for objective evaluation of the efficacy of treatment .
it is noteworthy that not only exercise but also the psychological interaction between patient and clinician during running sessions positively influenced the treatment .
exercise therapy may be incorporated to enhance multifactorial treatment , such as treatment including pharmacological , psychological , and occupational methods , as a way of strengthening resilience .
this case implies that exercise has considerable potential to treat hikikomori , implicating cerebral plasticity measured as the neurophysiological biomarker .
 =  deoxygenated hemoglobin   =  near - infrared spectroscopy  =  oxygenated hemoglobin  =  region of interest  =  verbal fluency task
each author participated sufficiently in the work to take public responsibility for appropriate portions of the content .
written informed consent was obtained from the patient for publication of this case report and any accompanying images .
 
 severe social withdrawal , called hikikomori , has drawn increased public attention . however , an optimal 
 clinical approach and strategy of treatment has not been well established . here 
 , we report a case of hikikomori for which an exercise intervention 
 using jogging therapy was effective , showing cerebral hemodynamic improvement . 
 the patient was a 20 year old japanese male who was hospitalized in order 
 to evaluate and treat severe social withdrawal . 
 although depressive and anxiety symptoms partially subsided with sertraline alone , social withdrawal persisted due to a lack of self confidence . with his consent , we implemented exercise therapy with 30 minutes of jogging three times a week for three months . 
 we did not change the pharmacotherapy , and his social withdrawal remarkably improved with continuous jogging exercise . using near infrared spectroscopy to evaluate hemodynamic alteration 
 , bilateral temporal hemodynamics considerably increased after the three - month jogging therapy . 
 regarding exercise therapy for mental illness , numerous studies have reported the effectiveness of exercise therapy for major depression . 
 this case implied , however , that the applicability of exercise therapy is not limited to major depressive disorder . 
 jogging therapy may contribute to reinforcing self confidence associated with  
 resilience  in conjunction with neurophysiological modulation of neural networks . 
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