What I'm sharing is simply personal experience and does not constitute a medical advice. Still, I'm hoping it's good for thought for others facing similar questions on dealing with children (on or not on the spectrum) and anxiety.
I know many people will say that boys and girls have increased anxiety around puberty and that it's a phase and they all make it through. Yes, for most, that is the case. Whenever friends or family would deliver that sage advice to me, I'd describe my children's' anxiety attacks. They maxed out around 3-5 times a week of uncontrollable crying (anywhere from 30 min to 3 hours), running out of class, hiding under beds or in closets, being completely non functional (almost catatonic) for many hours (2-6 hrs) after the attack, etc. My friends would then say, "Oh, that's not normal." Correct, hit the nail on the head. Anxiety that requires clinical intervention looks notably different from kids who are moody, cry occasionally, seem anxious about friends or school. Clinical anxiety disorder is debilitating and interferes with your ability to function in life.
A summary of previous posts of Ethan's experience: When Ethan was around 10 years old we began to see an increase in his emotional outbursts and generally having difficulties dealing with simple problems or unexpected things. We deemed it 'lack of emotional regulation' but it was at its heart off the scale anxiety. Ethan continued to have quite a bit of Cognitive Behavioral Therapy (CBT) to try and deal with it, but as he aged, his anxiety seemed to worsen. We tried Celexa (Citalopram). Trying an SSRI on an autistic 11 year old requires very low dosage start and slow ramp up (and subsequent ramp down and off). It took about 4 months to realize it wasn't benefitting him, and another 6 weeks to come down and off. A doctor (an autism expert that Ethan had seen during medical clinical trials) encouraged us not to give up on SSRIs for everyone has different biochemistry and it can take a few tries to find a match. So we tried Prozac and pretty quickly saw it as a game changer for Ethan. It allowed him to function at school and the classroom, at home, and out in the world. It's not a miracle pill that suddenly vanishes all anxiety, it reduces it to a manageable level. It allowed for Ethan to employ all the calming and CBT techniques he'd learned over the past years because he was no longer in an unreachable anxiety attack at the slightest thing. He's been on Prozac (fluoxetine) for 6 years now, with no side effects and no need to increase his dosage from where he originally settled in.
Fast forward a few years and our neurotypical son has been suffering from crippling anxiety. It was affecting him at school and at home. We started him on Talk Therapy and CBT. It was useful for him, but his attacks were becoming more frequent and more debilitating after 6 months of therapy. So we considered evaluating SSRI's. We picked Prozac to start since it had been successful for his brother. He ramped up on it over several months. We saw no change, so he ramped down. Our psychiatrist then suggested to try Lexapro (Escitalopram). He ramped up on it over several months. We saw no change, so he ramped down. Trying those two SSRIs took up his entire 8th grade school year. That summer we kept him off any new meds. He was miserable. No school work, just fun summer camp, and he was still plagued by anxiety attacks. I was beginning to despair.
Then just before he started high school he switched to a new psychologist (talk therapy) that he really liked as well as started to take Zoloft (sertraline). After just a second ramp up on dosage, we began to see change. The next step up in dosage, we saw the elimination of the full blown anxiety attacks. Again, I'll reiterate, it's not that all anxiety is eliminated, it's reduced to a manageable level. He was able to employ all of the CBT techniques for dealing with his anxiety now that the attacks weren't so powerful and debilitating. Therapy and medication work hand in hand for maximum efficacy. Study that sort of proves the obvious here---> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702984/
So for our youngest child, it took trying 3 different SSRIs to find a match. He's been on it for 8 months now and doing well at functioning with his anxiety.
It's easy to dismiss anxiety in adolescents, but if you can help them at a young age, it can only benefit them as adults. There are also a lot of wannabe clinicians out there who read a few headlines and say there are no medications for autism. To that I wish to educate you and say, there are many other disorders that are very prevalent as concomitant diagnosis with autism (seizures, anxiety, OCD, ADHD, etc.). There are many medical treatments for these and while there may or may not be improvement in other autism symptoms when treating, the improvement in the targeted area (in our case 'anxiety') leads to improved life functionality.