I agree but also disagree.
I'll try and explain why.
I agree mental.illnes and neurodivergent conditions like ADHD and autism are on a spectrum.
You may very well have proportion of people with anxiety and depression who actually with the right support, be that medication or therapy can recover to a point here it does not affect their life so negatively and to such a degree. On the other hand you have others with anxiety and depression who have suffered/lived with it for decades despite having all the treatment and it does not improve or realistically is ever likely to.
Equally with ADHD and autism. Again you have a sprectum. For the most severely affected it can have a devastating and limiting effect in their lives. But no two people are the same. As ten DWP like to tell you it's not the condition you have but how that condition affects you (at least 50% of the time).
Personally I've never exaggerated my mental illness symptoms, I've always been honest.. unfortunately due to the strict criteria (and yes I know someone will be alone to say my neighbours nephew's daughter got it with Jo evidence) that has gone against me. I admit I don't currently have any "specialist mental health input" (I mean ignoring the ADHD specialist apparently) but that doesn't mean I don't have severe and ending mental illness.
I've been mentally ill since I was 11, when I first experienced depression..I was 12 when I started self harming and when I first attempted suicide.
My mental health progressively got worse and tbh I lost most of my tweens and twenties to it. My last attempt was aged 21 and that led to me losing u job and ending up cliamif ESA. I was put in the support group for the 3 1/2 years I was on it as I qualified under "work or work activity being a substantial risk to life".
I was after 3 1/2 years of having ACTUAL mental health care (in the form of a regular psychiatrist, community psychiatric nurse and occupational therapist) able to come off ESA and return to work which I've now been doing 12 years, but without that support I'm honestly not sure I'd even be here typing this now.
I do agree that for some, especially those in co current drug addictions, PIP imo is not particularly useful. Tbh I've seen what happens, often they get the money, they get their fix and after it's gone resort to begging or shoplifting. Obviously you cat force someone to accept help or treatment but I do question whether it's the right support.