Seasonal Affective Disorder is a rather common condition in the Nordic countries. Long and dark winters cause this type of periodic depressions that vanish when spring arrives.
Phototherapy and sleep deprivation
SAD can be treated with phototherapy whereas depression in general, can be sucessfully treated with MAO inhibiters or other drugs that blocks the reuptake of serotonin. Mind you, depression can also be treated with speep deprivation and exercise. A positive solution as side effects are few.
Orthorexia lack restitution
As for Eating disorders and Orthorexia, depression can be a condition that arise due to lack of energy. Craving for carbohydrates is a common symptom for Orthorexia as well as for SAD. Sleep deprivation is not a suitable treatment for othorexics, who already lie sleepless due to anxiety.