Diagnosing Depression in Autism

What’s going on?

The symptoms of depression may be harder to spot, or confusing, in someone like Mark. “High-profile problems such as aggression or self-injury tend to draw clinical attention away from less dramatic” issues, such as depression and anxiety, according to some researchers.⁴

“We don’t think enough about depression with this population,” said Desmond M. Kaplan, MD, former founding Service Chief, Child and Adolescent Neuropsychiatry Unit, at Sheppard Pratt Hospital near Baltimore. The unit treats children with autism and other developmental disorders, and is part of the Autism Inpatient Collection (AIC) research project.

“I would venture to say depression is fairly common in children and adolescents with autism, but it’s under-recognized,” said Rajneesh Mahajan, MD, a child and adolescent psychiatrist on the same Sheppard Pratt Unit, and a faculty member at Kennedy Krieger Institute.

Symptoms of depression may hide behind common features of autism, such as an emotionless expression or voice, sleep problems, and trouble concentrating, according to research.^{5, 6, 7} Or its symptoms may differ from textbook examples. Rather than looking tired and sad, a depressed person with autism may be irritable or agitated, or have emotional outbursts.^{4, 7, 8, 9}

Unfortunately, there are no lab tests or scans for depression in children or adults. Doctors typically rely on a patient’s ability to convey his feelings. That’s a heavy burden for people whose autism impairs their ability to communicate through words or facial expressions. Even an adult with fluent speech may struggle to describe his feelings as depression. A small study of adults with Asperger’s Syndrome and autism revealed that they had more trouble identifying and describing their emotions than other people – and were more depressed. For the study, those adults completed questionnaires measuring depression and alexithymia, which is a difficulty identifying one’s own emotions.¹⁰

Children and teens may not be able to label their feelings as guilt or worthlessness – some of the feelings doctors are looking for when considering depression. For those and other reasons, some researchers developed a tool for diagnosing other psychiatric disorders in children with autism. Using the tool, called the Autism Comorbidity Interview (ACI), the researchers found that 10 percent of the children they studied had had at least one episode of major depression while another 14 percent fell just below the threshold for the illness.⁹ (Co-morbidity means a second or third illness that occurs at the same time as the first condition, in this case, autism). The ACI is a research tool that is not typically used by mental health providers treating patients with autism.

What’s the true depression rate in autism?

“We don’t understand why adults with autism have higher rates of depression and suicide.” – Dr. Croen

Research into children and adults points to rates of depression that range from a low of 1.4 percent to a high of 57 percent, with most studies finding somewhere in between.^{1, 11-15} A large study of adults found that 26 percent of those with autism had had depression, compared to just 10 percent of adults who didn’t have autism. That study looked at the medical records of 16,500 patients, including 1,500 with autism, in the Kaiser Permanente health plan in Northern California. Almost 2 percent of the ASD adults had tried to kill themselves, compared to less than one-half of one percent of the other adults.²

What the study couldn’t say is why. “We don’t understand why adults with autism have higher rates of depression and suicide,” said Lisa Croen, PhD, director of the autism research program at Kaiser Permanente Northern California. “More research is needed to understand the basis for these findings: Is it genetic predisposition? Social isolation? Complications from medications?”

Studies of children and teens, including those by the Interactive Autism Network found depression rates around 7 to 12 percent,^{11, 16, 17} with rates as high as 30 percent in Asperger’s Syndrome, a form of “high functioning autism.”¹⁴ A large study by Penn State University researchers found an even higher rate of “depressed mood” – not necessarily depression – in children with autism, based upon reports from their mothers. This justifies “routinely assessing all children with autism for depression,” according to a team led by psychologist Susan D. Mayes.¹³

When should families or doctors suspect depression?

Sometimes parents, caregivers or teachers assume that changes in a child’s mood or behavior are part of autism, when depression or another condition may be to blame.

Doctors and researchers alike say it’s important to examine changes in someone’s behavior, such as sleep and eating habits, irritability, or agitation levels. This is crucial if the person cannot say how he is feeling. “What’s really most important, if you are not getting sufficient information about their inner world, is their functioning, and whether that has changed,” Dr. Kaplan said.

Doctors may rely on information from parents, teachers or others about changes in a child’s behavior, school, or home life. The risk factors for depression in ASD are similar to those in people who don’t have autism: a family history of depression⁷, a traumatic event,^{1, 18} or the beginning of puberty.

“Typically, I think developmentally when I’m evaluating children,” explained Dr. Mahajan. “For example, when I see younger children, I’m thinking more about ADHD and anxiety, not necessarily depression, but by 12 or 13 years of age, I start thinking about emerging depression or bipolar disorder, in addition to ADHD and anxiety, especially if there’s a family history. On the other hand, this does not mean that younger children may not experience sadness or depressed mood and therefore should be screened, based on changes in functioning and behavior.”

Risk factors for depression

“It’s like having to play a game of Monopoly every day of your life, but the standard for everyone else when they roll the dice is that they get to move forward, but when I roll the dice, I have to move backward.” – Kate Gladstone

People with “high functioning autism” – that is, people who are verbal and don’t have intellectual disability – may possibly be at higher risk for depression, according to Dr. Mahajan and several studies. Those children “may be more vulnerable to develop depressive symptoms just because they may be in mainstream classes with peers who are relatively more socially able than they are, and that may set them up for low self-esteem, and social isolation,” he said.

Some studies show a higher risk for depression^{13, 16} and possibly suicide¹⁹ in “high functioning autism.” It’s unclear, however, if that is because it’s easier to diagnose and study people with depression who can verbally describe their moods.

Another factor to consider: bullying is linked to depression in typical teenagers.²⁰ A study by the Interactive Autism Network found that children with autism were bullied at a rate three times higher than that of their typically-developing brothers and sisters.²¹

Kate Gladstone, 53, a business owner with Asperger’s, believes the experience of “being bullied all your life” takes a toll on the emotional health of some people with autism. Social situations are stacked against anyone who appears “different,” she said. “It’s like having to play a game of Monopoly every day of your life, but the standard for everyone else when they roll the dice is that they get to move forward, but when I roll the dice, I have to move backward.”

Some aspects of autism may contribute to depression. For example, rumination – thinking over and over again about things that upset you – is a risk factor for depression in the general population. People with autism have repetitive motions and obsessive interests – which may be related to rumination.^{22, 23} Another study found a link between depression and the planning and organizational problems often experienced by people with autism.²⁴

Understanding Depression in Autism

Katherine Gotham led a social group for adults with ASD when she was a graduate student in clinical psychology some years ago. Several of the members would “cycle in and out of depressive episodes,” she recalled. “Others struggled with ongoing depression, and of course, others were never depressed throughout the time we knew them.”

At first, she thought that their depression was fueled by problems they had in achieving their goals, such as romantic relationships, jobs, and greater independence – goals made more complicated by their ASD. But then something happened that caused her to re-think those assumptions. Her colleagues helped a group member with ASD find a job. Although the man seemed to love the work and liked his co-workers, he became depressed again and had to quit his job. “I realized that maybe the ‘obvious’ reasons weren’t the whole picture in understanding depression in ASD.”

Dr. Gotham is now an assistant professor of psychiatry at Vanderbilt University, and has researched depression in autism. “Years later, I now see that there are likely many reasons for high rates of depression in ASD – some psychosocial, others neurobiological – and that these potential mechanisms interact with each other in different ways within individual people. So, like most things in science, we’re probably not looking at just one story for why people with ASD become depressed.”