Adults Diagnosed with Autism Later in Life Reveal How They Felt like 'Bad' People: 'I'd Always Felt like This Alien'

People diagnosed with autism later in life have revealed how not knowing for decades that they had the condition made them feel "alien" and like "bad" people.

The condition can be diagnosed at the age of 18 months, with a series of behavioral and developmental tests. However, autism was first included in the manual of mental disorders used by qualified health professionals in 1983, meaning those who grew up before this time went under diagnosed or misdiagnosed, researchers explained in a study published in the journal Health Psychology and Behavioral Medicine.

To understand the impact this may have had on these individuals, autism experts interviewed nine adults aged over 50 who had recently been diagnosed. Five were female, and four were male.

Asked why they had sought a diagnosis, three of the participants said their children had been told they had autism, and they recognized similar symptoms in themselves.

The remainder were advised to seek help from a loved one, such as their partner or family member, or a therapist treating them for a separate condition.

As people with autism can struggle with face-to-face communication, the researchers tried to make the participants feel comfortable as possible, from interviewing them over Skype and email, to finding a quiet area for a chat in a hotel lobby.

The interviewees all loosely covered topics including early signs which suggested they had autism, their awareness of being different, how it felt to be diagnosed, and how it affected their lives.

All of the participants said they had been treated for anxiety and depression.

Several traits characteristic of autism kept coming up in the interviews, including participants recalling feeling socially isolated and as if they had failed to "fit in." They also demonstrated repetitive behaviours, and a fondness for routine.

"I've never had friends; I've never made friends," said one participant.

"I'd always felt like this alien...I feel like I'm a different type of human to nonautistic humans," another recalled.

Many said that they thought they were a "bad person," which they reasoned might explain why they weren't liked.

Another said: "I was completely isolated and always in trouble, pretty strongly disliked by a lot of people...I tried to be friends with people and just got rejected. I don't know why."

And while the interviews spoke of a sense of "relief" at being diagnosed with autism, they also noted it lead them to rethink how they viewed themselves.

Having an explanation for their differences helped them to gain a better understanding of their reactions and behaviours to certain situations, the participants said. This in turn enabled them to gain more control over their lives.

Co-author Steven Stagg, an expert in child development at Anglia Ruskin University, told Newsweek: "I was surprised by the fact that all of the participants had thought they were terrible people before receiving their diagnosis.

"Having autism had made work and relationship experiences very difficult for them. They often found themselves isolated at work and disliked by colleagues. Some participants had multiple jobs throughout their lives because they had experienced bullying at work and had left their jobs or had been forced to leave.

"Their autism would have meant others saw them as unfriendly, too direct, not able to manage social norms, but they were unaware of this," said Stagg.

However, being diagnosed enabled some of the participants to notify their employers about their condition so they could make adjustments to make work more satisfying, said Stagg.

He acknowledged the study involved, albeit detailed, interviews with only nine participants. But Stagg explained the team put out requests across the appropriate blogs and social media platforms, and struggled to recruit participants.

"We have undoubtedly not covered all the issues recently diagnosed adults with autism face," he said.

Due to the link between anxiety, depression and autism uncovered by the research, Stagg argued those accessing mental health services for these conditions should also be screened for autism.

"Some participants were treated for anxiety and depression for years before a health worker suggested the issues may stem from autism," he said.

"I also think the research will help employers to become more aware of the difficulties individual with autism face at work and how small adjustments can help alleviate difficulties," Stagg added.

And while awareness of autism has grown in the past few decades, people with the condition still face obstacles when it comes to being diagnosed, including the persistent "cliche of the male savant."

"There are still individuals that go undetected, and autism in women and ethnic minorities is still less likely to be detected than autism in white males," said Stagg.

People who are worried they have autism should first read up about the condition, and take a screening test such as the autism quotient. Next, they should speak to their family doctor, or first contact a major autism charity if that would make them feel more comfortable in approaching a healthcare professional.

"It [the study] tells us that even if you have lived all of your life without the diagnosis, finding out that you have autism can be a very positive experience," said Stagg.