Be advised about the "8-year rule", as it stands there is no medical retirement for Neurodevelopmental Disorders (ADHD, Autism, Down's, FAS, Learning Disabilities, etc.) or Personality Disorders by themselves, even if the servicemember surpassed 8 years TIS. Those conditions, by themselves, if retention is not recommended, are dealt with by the admin sep process as "Unsuiting" (even if implicated at 14+ years TIS), not the DES (DES requires potentially "Unfitting" conditions), though generally upon reaching 6 years TIS the servicemember becomes eligible for an admin sep board to contest an "Unsuiting" mental health admin sep recommendation.
(Disclaimer: Has anyone slipped past all the rules and medically retired due to a "service-connected" Personality Disorder diagnosis when it was supposed to be dealt with as "Unsuiting"? Yes. But these people got extremely lucky. In all U.S. military history the total amount of people that have slipped past all the rules this way is probably in the low double digits. The branches keep access to the DES and medical retirement locked down tight nowadays. Do not count on any lucky accidents like that happening anymore.)
Although 10 USC §1207a (the "8-year rule" law) reads like it's supposed to convert an "Unsuiting" pre-existing mental health condition not amounting to a disability, like Autism, into an "Unfitting" disability eligible for the DES and medical retirement and all that good stuff given 8 years TIS... be advised that in reality 10 USC §1207a does not work for Neurodevelopmental Disorders and Personality Disorders, though it is wishful thinking.
The only "Unsuiting" mental health condition that can convert into a potentially "Unfitting" condition is Adjustment Disorder, if the disturbance lasts at least 6 months in service it is considered no longer "Acute"(Unsuiting) but a "Chronic"(potentially Unfitting) Adjustment Disorder eligible for referral to the DES. This is independent from 10 USC §1207a. (Anyone who was admin sep'd for Adjustment Disorder but met "Chronic" criteria in service should file a BCMR/BCNR request for retroactive medical retirement, as they should have been referred to the DES.)
By all means, DoD Instruction 1332.18, Disability Evaluation System, Section 1, Policy Paragraph "l."(lima) is written (and has been explicitly rewritten under "Incorporating Change 1, Effective May 17, 2018" when this paragraph was Policy Paragraph "i."[india]) to the effect that a servicemember with both Unsuiting and potentially Unfitting conditions is absolutely eligible for referral to the DES due to the potentially Unfitting conditions.
However, people in the services (commanders, medical, Pre-DES, and DES) often like to pull a fast one by trying to make the Unsuiting condition derail the potentially Unfitting condition, even when over 8 years TIS. Watch out for this. Though MEB request paperwork can make mere mention of Unsuiting conditions, it is not supposed to be referred for the Unsuiting conditions or else it'll be shot down and the servicemember can find themselves on the streets on admin sep! Potentially Unfitting conditions (i.e. PTSD, Other Specified Trauma and Stressor-Related Disorder, MDD, GAD, Chronic Adjustment Disorder, Schizophrenia, Bipolar, etc., and of course the myriad of physical conditions) must always be the the driving factor of an MEB request even when over 8 years TIS.
For OP, this means they better not have messed with your depression/anxiety diagnosis. If they request MEB it's supposed to be for your depression/anxiety or something else potentially "Unfitting", not any Neurodevelopmental Disorder.