Can Rispiridone Tablet Cause Erectile Dysfunction?

I am 28, male, and I am taking rispiridone 1.5 mg/day now for about 8 months (at beginning it was 5 mg/day) and my doctor scheduled to take it another 3 months. The problem is that I can't get an erection nor sexual drive or very low. I can hardly get an errection and I produce no sperm at ejaculation. I also cannot sustain the erection for more than 20-30 seconds.. :(

My doctor is telling me that its a mental thing and that I worry to much. She also told me its a reversible condition.

I should mention that when I was taking 5mg/day for about 2 months I was getting the rare side effect of prolonged painful errection for about 1-2 hours every night.

Are my penis muscle affected or its a reversible condition after I stop taking rispiridone ?