"People who have disabilities deserve to have fun too," says Comic Con fan Kaitlyn Lundy.

The 23-year-old has anxiety and depression and for the past three years Kaitlyn has travelled with her service dog Lilo from Phoenix Arizona to San Diego to attend Comic Con, an annual event that attracts thousands of people.

On Saturday, the busiest day at Comic Con, Kaitlyn met me at an entrance of the San Diego convention centre. It was a bright sunny morning and the place was brimming with attendees, some in bright extravagant cosplay, others excitedly talking with friends and family about the day's events.

Image caption Kaitlyn attending San Diego Comic Con in a Handmaids Tale costume with her service dog Lilo

As I arrived I noticed how busy it was. It was early, but there were already hundreds of people waiting to get in. Volunteers and officials were asking people to show their passes as they entered, and the consistent beeps of passes being scanned remained in the background.

Kaitlyn in cosplay was dressed in a bright red Handmaid's Tale costume with Lilo by her side.

She smiled as we met and it was hard to imagine that she'd used every ounce of energy just to be here.

Comic Con, an annual fiesta of costumes, comic books and celebrities, sits at the centre of a multi-billion dollar industry. What once began as a gathering of less than 300 people in 1970 has evolved into an annual four-day event attracting major corporate sponsors, movie studios and more than 130,000 people.

"It's very overwhelming, people bumping into you, and talking to you, but this is a great place to be, it's full of people who feel like they don't fit into regular society," she told me.

You may also like:

As we look for a place to talk Kaitlyn says people often ask her why she would put herself through the stress of navigating huge crowds when she has anxiety.

"Just because you're depressed doesn't mean you cant try to smile, you have to learn to manage it and be prepared for it.

"Panic attacks are like a headache, you can feel them coming along. It always kinda feels like it's about to hit. I get breathless, anxious. It makes me wanna cry.

"I want be here and having fun but then your body and mind is telling you, 'No, you can't do this. Get away from all these people.' So having Lilo is like someone saying, 'Ignore them, focus on me.' She helps a lot."

Image caption Kaitlyn and Lilo take time out of the convention to rest

As we rest against a wall by the entrance Kaitlyn tells me she has been in therapy since she was a child, and was prescribed medication for her anxiety and depression in middle school. In addition she has fybromalgia which causes chronic pain and severe fatigue.

"People say things like, 'Why do you have a dog? You're not disabled.' But not all disabilities are visible," she says.

Lilo appears to know she is being spoken about and as Kaitlyn describes how much having a service dog has helped her, Lilo affectionately lays her head on her lap and the two share a tender moment.

"My mum comes to Comic Con with me but having Lilo helps so much," Kaitlyn says patting Lilo on the head.

"We can't say to people, 'Move out of the way, I'm anxious', but when they see the dog, they naturally give me some space.

"I've learnt to manage it because I think if she can walk through the crowds and get pushed and prodded then I can."

Image caption Lilo is a service dog who is trained to help Kaitlyn when she has anxiety attacks

Service dogs are trained to help a person who has a disability such as mobile, hearing or visual impairments. In recent years more service animals have been trained to detect abnormalities such as changes in blood sugar levels in diabetes patients or those with mental illnesses.

Lilo is trained to detect changes in Kailtlyn's mood. When Lilo senses a panic attack she forms a circle around her and pushes her nose into her leg.

On the second day of the convention, Kailtyn described how "an overwhelming feeling" came over her and she was forced to leave.

"I was here for an hour and I started to feel the panic attack coming on. I wanted to cry.

"I was in a bad mood and I wanted to get out of there."

Image copyright Kaitlyn Lundy

Kailtyn said she spent the rest of the day in her hotel room resting which she said she felt some guilt about.

"I was dressed up as The Little Mermaid that day and so many people were asking for photos. I had to say, 'Sorry, no.' Most people were very understanding. I did let the little children take pictures, though, because I love the reaction to them seeing their favourite character with a service dog.

"But I ended up missing a whole day of Comic Con. There are people who would love to be here in my place and who try so hard to get tickets, but I definitely would not have been able to enjoy the rest of my experience if I hadn't taken that time out for myself."

Kailtyn says her anxiety is "always going to be there" but advises others with the condition to be prepared: "Take time out for yourself, but connect with other people. We are like a family. I know what you're going through."