02/28/2014 AT 09:30 PM EST
A judge ordered Chris Brown
to stay another two months in a Malibu rehab, where doctors blame the R&B singer's violent past on previously undiagnosed PTSD and bipolar disorder and say he is making great progress while becoming less impulsive.
Although a report reviewed by the judge says the singer tells doctors he "is happy with the program," Brown, in court Friday, seemed disappointed
by the decision to extend his rehab stay.
"It is evident that [Brown] has responded well" to the treatment, a probation officer wrote to the court. However, the officer said that Brown's positive change in behavior "has occurred only recently" and the court should be cautious about releasing him too soon and should keep him on probation until November.
Brown, 24, was originally placed on probation for his 2009 attack on his then-girlfriend Rihanna
hours before the Grammy Awards. He was sentenced in November to three months of in-patient rehab after he was charged with misdemeanor assault after his involvement in a fight
in Washington D.C. The judge in Los Angeles could penalize Brown further if he is convicted in the Washington case, which goes to trial April 17.
According to a letter from the facility treating Brown, he has a very regimented life in rehab, waking at 5 a.m. every morning and doing 24 hours a week of community service as well as six to eight therapy sessions per week "with his team of clinicians and doctors to address his bipolar diagnosis, anger management, post-traumatic stress disorder and past substance abuse."
The letter says that Brown "continues to make great strides" but he needs to continue "intense individual, family and medical follow-up over the next year so he can sustain the changes."
It also says that Brown needs close supervision by his doctor "to ensure his bipolar mental health condition remains stable. It is not uncommon for patients with post-traumatic stress disorder and Bipolar II to use substances to self-medicate their biochemical mood swings and trauma triggers. Our clinical team believes Mr. Brown became aggressive and acted out physically due to his untreated mental health disorder, severe sleep deprivation, inappropriate self-medicating and untreated PTSD."
The letter goes on to say that, despite all of his legal troubles, Brown is learning how to control his anger and he is recognizing the error in trying to treat his problems with substance abuse. If Brown continues on his current path, he can "become the positive role model in society that we believe he truly desires to be," the report concludes.