Stepho Wilson had her first bout with depression when she was a teenager. She was struggling with feelings of loneliness and isolation that eventually developed into suicidal thoughts after all her older siblings had flown the nest and she was the last one left at home. Eventually, after the birth of her daughter, now 7, Wilson was diagnosed with major depressive disorder. But none of the medications she tried – antidepressants, antianxiety meds, antipsychotics – seemed to help.
Finally, Wilson got her depression under control with a combination of oral and injectable ketamine, an anesthetic used in treatment-resistant depression. But even then, she’d have occasional flares of extremely low mood that could dog her for days at a time. When she asked her doctor if there was anything else she could take on those days, the doctor offered stimulants.
“The way that they altered my brain and the way that I described that to my doctor — that was the first time that someone asked me, ‘Have you ever thought you had ADHD?’”
All those years that she’d been struggling to get her depression under control, untreated ADHD may have been making it worse.
An estimated 1 in 5 people with ADHD — and possibly up to as many as 1 in 2, some studies suggest — also have depression. That makes people with ADHD two to six times more likely to develop depression than people in the general population. The challenges of living with ADHD, especially when it’s untreated, could be cause for depression in some people, but that’s not the whole story.
“The chronic life stressors that come from ADHD contribute to depression,” says Muhammad Minhaj, MD, a primary care provider at Houston Methodist, “but ADHD and depression also have shared genetics and brain chemistry.”
The Burden of Life With ADHD Could Lead to Depression
ADHD starts in childhood. Though Wilson didn’t have a diagnosis until she was in late 20s, she had always been aware of, what she later learned were, her symptoms of the condition. “Inability to focus, impulse control issues, and being easily overwhelmed,” she says, describing the ways ADHD affects her.
When it’s not caught and treated early, it can lead to a lifetime of struggling and failing to meet expectations — at school, then later at work and in relationships. This can cause low self-esteem or poor self-image, and these issues can be a recipe for depression.
“Untreated ADHD can really wreak havoc on your life — sleeping habits, eating habits, time management, relationships, creating problems in all of those domains, which can then impact mood,” says Roberto Olivardia, PhD, a psychologist who specializes in ADHD at Mass General Brigham McLean Hospital in Belmont, Massachusetts. “In addition to that, one of the functions that ADHD affects is emotional regulation.”
Emotional Dysregulation in ADHD
It’s well known that ADHD steals focus and triggers hyperactivity, but it also affects emotional regulation, which can cause a lesser known symptom called rejection-sensitive dysphoria.
This aspect of ADHD is not as well understood as its effects on focus, organization, and executive function. But what is known is that the brain of a person with ADHD doesn’t process and filter internal signals in the same way that a neurotypical brain does. In some people with ADHD, this can lead to severe emotional pain in response to a real or perceived rejection or failure, which may seem to neurotypical people like an extreme overreaction to the situation.
To put it all together, a person with ADHD may indeed be failing at work, school, or in their relationships, which would make most anyone feel pretty low, but in the ADHD brain, these failures — or being told they’re failing — may feel unbearable. It might make sense then why poor emotional regulation may increase risk for depression in people with ADHD.
Wilson says her ADHD makes her more likely to slip into a bout of depression. “I feel like I get so easily triggered into a depressive episode because people with ADHD can be easily overwhelmed,” she says. “We’re very sensitive emotionally.”
ADHD and Depression Affect Common Brain Centers
At this point, it shouldn’t come as a surprise that ADHD and depression affect some of the same parts of the brain.
Brain scans of people with ADHD have shown, for example, that the prefrontal cortex — a part of the brain involved in attention, emotions, self-control, and decision-making — develops and reaches maturity more slowly than it does in other people. This delay, and the impact it has on certain skills, seems to increase risk for depression during the critical transition from childhood to adulthood.
ADHD and depression have each been individually linked to having a smaller hippocampus, the part of your brain responsible for memory and learning. In people who have both ADHD and depression, the hippocampus appears to be even smaller than in someone who only has one of these conditions.
ADHD and Depression Share Common Genetics
The similarities don’t stop there. Groups of genes may be working together to drive development of both of these conditions.
“Most people with ADHD have another disorder,” Olivardia says. “If not one, the most common is two or three. It’s the rule rather than the exception.”
Among adults with ADHD, the most common co-occurring condition is depression. Research shows that people who have ADHD not only typically carry genes and proteins that are linked to the condition, but they also very often carry other genes and proteins that are known to be connected with depression, too. These biological traits tend to come in clusters.
ADHD and Depression Can Look Alike
Maybe in part because of these shared biological features, ADHD and depression have quite a few symptoms in common.
“Both conditions can cause poor focus, forgetfulness, low motivation, and task avoidance, all of which are often mistaken for laziness,” Minhaj says.
The difference, he explains, is that when those symptoms are caused by ADHD, they are present, in some way, from childhood. When depression causes these symptoms, they can arise at any time and may only last for a few weeks or months.
While people with either one of these conditions might struggle to follow through on and complete tasks, there’s an important distinction, Minhaj says. “On the ADHD side, motivation is present but execution is impaired, while on the depression side, motivation is absent.”
Both Conditions Need Treatment
Wilson, who also lives with anxiety in addition to ADHD and depression, says the three conditions fuel each other. “I already struggle with executive function. In ADHD, that already happens naturally. Even when everything’s going well, that’s a roadblock. But then add to that the potential for not having the energy to get out of bed. That just amplifies it.”
It’s important to get ADHD under control first, Olivardia says. “Untreated ADHD can undermine the treatment of anything else.” What’s more, he adds, some people who are battling the symptoms of both ADHD and depression find that their depression-like symptoms clear up completely once they get their ADHD under control. It makes sense: You’re more focused and functioning better, so you just feel better.
That said, given that at least 20% or more of people with ADHD also have depression, most people will need treatment for both. That may include medications called stimulants for ADHD, antidepressants for depression, and therapy that addresses both the conditions together.
“The overlap in treatment is on the side of cognitive behavioral therapy, or psychotherapy, and lifestyle interventions,” Minhaj says.
Getting the right treatment for each condition could make a world of difference in both conditions. “Treating ADHD reduces the stress that fuels depression,” he says, “and treating the depression boosts your energy to manage your ADHD.”
