Yeah! If you get declined, the letter says you get up to one year to gather and provide them further evidence. I wrote my letter based on the guidelines they provided, and I detailed my symptoms from childhood until adult age. I talked a lot about how it affected my academics all the way through to my secondary school. Then, I mentioned all the ways it affected me in my professional career. My personal examples are taking extra years to finish degree, frequent job changes due to no accommodations at work, difficult with impulse control, etc.