<P> Bright light therapy reduces depression symptom severity, with benefit was found for both seasonal affective disorder and for nonseasonal depression, and an effect similar to those for conventional antidepressants . For non-seasonal depression, adding light therapy to the standard antidepressant treatment was not effective . For non-seasonal depression where light was used mostly in combination with antidepressants or wake therapy a moderate effect was found, with response better than control treatment in high - quality studies, in studies that applied morning light treatment, and with people who respond to total or partial sleep deprivation . Both analyses noted poor quality, short duration, and small size of most of the reviewed studies . There is insufficient evidence for Reiki and dance movement therapy in depression . </P> <P> Major depressive episodes often resolve over time whether or not they are treated . Outpatients on a waiting list show a 10--15% reduction in symptoms within a few months, with approximately 20% no longer meeting the full criteria for a depressive disorder . The median duration of an episode has been estimated to be 23 weeks, with the highest rate of recovery in the first three months . </P> <P> Studies have shown that 80% of those suffering from their first major depressive episode will suffer from at least 1 more during their life, with a lifetime average of 4 episodes . Other general population studies indicate that around half those who have an episode recover (whether treated or not) and remain well, while the other half will have at least one more, and around 15% of those experience chronic recurrence . Studies recruiting from selective inpatient sources suggest lower recovery and higher chronicity, while studies of mostly outpatients show that nearly all recover, with a median episode duration of 11 months . Around 90% of those with severe or psychotic depression, most of whom also meet criteria for other mental disorders, experience recurrence . </P> <P> Recurrence is more likely if symptoms have not fully resolved with treatment . Current guidelines recommend continuing antidepressants for four to six months after remission to prevent relapse . Evidence from many randomized controlled trials indicates continuing antidepressant medications after recovery can reduce the chance of relapse by 70% (41% on placebo vs. 18% on antidepressant). The preventive effect probably lasts for at least the first 36 months of use . </P>

In major depressive disorder what percentage of patients will suffer a recurrent episode