13 year old - low mood and losing weight rapidly

Could she be in burnout? For myself, when the outside demands (which includes communicating) all become too much I start restricting my food as it's one thing I can control and the demands of having to eat is just too much. I am autistic with PDA profile. If she ends up under CAMHS and eating disorder services it vitally important they know how autism impacts her with food and eating. It's all too common that they ignore that and try to treat an eating disorder in the only they know how which can cause more harm to an autistic person. It might be worth a GP appointment and getting bloods etc done as it's the speed of weightloss that can cause health problems.

I hope I haven't spoken out of term, I'm going off my own experiences and from other online groups I'm in. There's a supportive Facebook group Autism and Eating Disorders for both adults and parents.

No, no you haven’t spoke out of turn at all. I actually think your scenario is more likely than an Eating disorder tbh. She is diagnosed with ODD and the low mood was there before the eating issues. This is why I’m worried to mention the eating to CAMHS because I don’t want it to overshadow the very obvious anxiety issues that I’m seeing. 

No, no you haven’t spoke out of turn at all. I actually think your scenario is more likely than an Eating disorder tbh. She is diagnosed with ODD and the low mood was there before the eating issues. This is why I’m worried to mention the eating to CAMHS because I don’t want it to overshadow the very obvious anxiety issues that I’m seeing. 

Thank you for this. Yes I will say clear boundaries is definitely what’s needed for her. Positive reinforcement has to be done in the correct way so as not to make the situation worse. It can definitely backfire if done wrong. I’m hoping CAMHS will help with a therapist because I agree, as much as she does still confide in me, a neutral person who isn’t her mum would definitely help.

Keelz said:

ODD is oppositional defiance its similar to PDA.

I notice the approach for dealing with ODD is quite different to PDA. Taken from the article https://inclusiveteach.com/2025/03/09/pda-vs-odd-key-differences-explained/

For ODD they suggest "Set clear boundaries, positive reinforcement"

Does she see a therapist? If so it may be worth asking them to talk about this with her and alert you if there is any action required, so long as it is in line with their ethics on disclosure.

If she doesn't have one then with ASD, ADHD and ODD as disgnoses then I think having someone she can confide in and who can offer her help to deal with all that is going on during will be of a lot of benefit to her.

I don't know if the CAMHS or your GP can help with this or whether it would have to be private.

The teenage years are often a time for the teenagers to pull away from their parents (they are not cool obviously!) so having this safe person to talk through her issues with and practice coping techniques with should help her in the transition to adult life.

It is never a cheap option of course - I think about £50/hour is the norm and will soon add up.

I also noticed some advice on strategies for coping with the ODD element:

https://drroseann.com/deal-with-oppositional-behavior/

I've not researched this in depth so cannot say if it is good or bad, but it appears to make sense. Just remember any CBT based therapies would need to be adapted for her autism as they do not typically work for us in their native format.

Good luck

Thank you. I appreciate that. ODD is oppositional defiance its similar to PDA.

You sound a caring and supportive mum

What is ODD?

If it were me, I would reduce demands where possible.