As this anabolic steroid is not very liver toxic, in-fact it is quite mild it can be used for extended periods of time; if you are not susceptible to DHT based side-effects you could reasonably supplement with Proviron the entire duration of your cycle. While it can be used for extended periods, as we will see dosing protocol can vary dramatically depending on the purpose for which it is used. If Proviron is being used simply as a quasi-anti-estrogen medication then a mere 25mg per day may be all you need but many will find 50mg to be needed if their cycle contains a high dosing of aromatizing steroids. For those who are supplementing for additional beneficial purposes higher doses may be needed; although 50mg will provide them solid effects a slightly higher bump may be needed. If you choose to use Proviron this is something you may need to play with as individual response will vary greatly. For the individual who supplements for the purpose of bridging, a rather common purpose of Proviron use, doses will necessarily be much higher, ranging from 100mg-150mg per day if the individual is going to obtain the desired effect and benefits.
Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.  The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.  Thus it is the challenge of competition among males of the species that facilitates aggression and violence.  Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.  The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males. 
In one small scale clinical trial of depressed patients, an improvement of symptoms which included anxiety, lack of drive and desire was observed.  In patients with dysthymia , unipolar , and bipolar depression significant improvement was observed.  In this series of studies, mesterolone lead to a significant decrease in luteinizing hormone and testosterone levels.  In another study, 100 mg mesterolone cipionate was administered twice monthly.  With regards to plasma testosterone levels, there was no difference between the treated versus untreated group, and baseline luteinizing hormone levels were minimally affected.