I want to use this post to talk about a branch of science I wouldn’t normally dive into: neuroscience, behavioral science, and endocrinology (the science of hormones). In short, mental health disorders.
Over the past few weeks, I’ve seen post after post on social media about mental health awareness. Many Facebook friends and family opened up about their struggles with things like depression, anxiety, bipolar disorder, imposter syndrome, Huntington’s Disease, and ADHD.
Mental health is a fascinating subject, but it doesn’t always get the right kind of attention. In 2010 the CDC and the Substance Abuse and Mental Health Services Administration (SAMHSA) surveyed adults in 16 states. Their goal was to gauge how the public views people with mental illness. Apparently, most adults agreed that mental illness treatment is effective, but very few — as little as 35% — agreed that people are “caring and sympathetic to people with mental illness”. In another 2010 study, also from the CDC, this number was even lower; as little as 25% of adults agreed that people are caring and sympathetic. I’ve cautioned you against citing personal anecdotes as a resource, but here’s one that seems appropriate, since I’m not actually using it to cite a claim.
I couldn’t focus as a kid. I was worried I might be stupid because it was so difficult to finish basic tasks. Oddly, the only thing I could ever do for longer than a few minutes was play the piano. I’d so often leave the dinner table mid-meal to play, my parents eventually had to bring the piano into the dining room so I could play while I ate. I’d often realize, out of the blue, that someone had been talking to me for a solid five minutes, and I’d have absolutely zero idea what they’d said. Not even enough to pretend I’d been listening. Also, weird things, like I used to have a compulsive need to start walking with my left foot, and I had mild verbal tics. Big surprise: I was diagnosed with ADD (as it was still known in 90’s). I’ve been on medication since then.
Still, as an adult, laundry stays in the washing machine for three days because I forget about it. I leave half-full glasses of water all over the house. I currently have 52 tabs open in 3 Chrome windows (yes, I counted). I’m used to slow computer performance. The other day I went into my bedroom to get my phone charger, but all I managed to do was change my shirt.
I’ve learned the importance of forming habits. I have to state, out loud, “I am putting my headphones in my front coat pocket” or I’ll have no idea where they went. My husband knows that if he puts something in my pocket for me, I will forget 30 seconds later. Most people have a place for everything; I have about 12 places, so if I lose something, all I have to do is make the rounds and I’ll probably find it.
Oddly, I developed exemplary time management. I have sticky notes all over everything. I write weekly, daily, even hourly to-do lists. Google Calendar is my Bible. That’s because I had no other choice if I wanted to function like a human being. If I hadn’t forced myself to learn how to get my sh*t together early on, I’d still be in the third grade, wearing mismatched shoes and punching kids because I thought they’d stolen my Magic Markers when really I just left them in the bathroom.
There’s a pretty significant stigma associated with mental disorders. The CDC found that only 20% of people with diagnosed or self-reported mental health issues saw a mental health provider in the last year. To this day, I am cautious of who I talk to about my ADD. Sometimes, when people find out, they say they’re surprised because they didn’t know I was “mentally disabled”. The education on ADD has been historically poor.
Like many health issues, mental or otherwise, many people don’t really know what ADD is. I’ve had several people doubt my diagnosis because I “don’t seem hyperactive”. I’m not and have never been hyperactive; there are plenty of people with ADD who aren’t. In fact, they have divided ADHD diagnoses into three different main categories, or subtypes: inattentive (ADHD-I) and hyperactive-impulsive (ADHD-HI). Some lucky people have a combination of both (ADHD-C).
I’ve never had my subtype officially diagnosed, but I’d bet money that I fit into subtype I for inattentive. My problem is focus, memory, and motivation… with some impulsiveness thrown in, which is why I’ve learned not to go shopping after my medication has worn off. Or the many, many times I’ve spontaneously cut my own hair.
There’s this thought that ADD is over-diagnosed, but I’m very lucky I was diagnosed early on and didn’t grow up thinking I was crazy or just plain stupid. It helped me learn that I was actually intelligent, although sometimes I forget it even now.
ADHD diagnosis — “could I have it?”
“Attention Deficit Hyperactivity Disorder (ADHD) is a brain disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.”
(National Institute of Mental Health)
This was my personal experience with ADHD; perhaps some of this sounds familiar. Symptoms vary a ton, but the main three categories are hyperactivity, impulsiveness, and inattention (or difficulty focusing). To be diagnosed, symptoms must be chronic, present before age 12, and severe enough to impair your ability to function in school, at work, or in relationships. (Check, check, and triple check.) They also can’t be due to some other disorder.
Ever wondered if you might have ADHD? Everyone likes a bit of self-evaluation; if you told me you’d never sat down and gone through the symptom checker on WebMD, I’d probably call you a liar. Below is a list of official symptoms within the two different ADHD subtypes. These come straight from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5), the authority on diagnosing mental health disorders.
According to the DSM-5, you may have ADHD as an adult if you’ve experienced at least 5 symptoms from one or both subtypes for at least 6 months.
- Do you have at least 5 symptoms of inattention, but not so much hyperactivity/impulsivity? You might have predominantly inattentive ADHD (ADHD-I).
- Do you have at least 5 symptoms of hyperactivity/impulsivity, but not so much inattention? You might have predominantly hyperactive/impulsive ADHD (ADHD-HI).
- Did you have at least 5 symptoms in each category? You might be one of the lucky people who have the combined subtype (ADHD-C)!
Here’s one thing to keep in mind: to receive a diagnosis, symptoms must be severe enough to impair your ability to function. My husband recently went in for an ADHD diagnosis, and he had 5 or 6 symptoms of hyperactivity/impulsivity. However, when the specialist asked him whether his symptoms significantly affected his quality of life, he said no. Therefore he was not diagnosed.*
*Question Everything: This is part of why people think ADHD is over-diagnosed; a big part of it is self-evaluation. Luckily, the way ADHD is studied is changing. More researchers are looking at the genetics of ADHD in addition to behaviors. Genetics are just as complicated as neuroscience, but gene markers can be extremely reliable when you’re diagnosing a disease. This will help a ton with diagnosis, and it will help to separate out the different subtypes.
So what causes ADHD?
The neurobiology of ADHD is super complicated, and the specific causes remain unclear. I’ll try to dig into the basics of what scientists think causes ADHD.
In the brain, neurons (brain cells) release chemicals called neurotransmitters. They regulate pretty much everything that has to do with your personality, movement, temperature control, and your ability to function. Three big neurotransmitters are thought to play a role in ADHD: dopamine, serotonin, and norepinephrine (NOR-eh-pi-NEFF-rin).
- Messed up dopamine.
First, dopamine. Two major dopamine pathways are thought to play a part in ADHD: the mesolimbic and mesocortical pathways. If you have about 8 minutes, watch this video from Khan Academy which gives an awesome explanation of where dopamine goes in the brain.
These dopamine pathways regulate the reward system:
- Motivation (“I want that cheese”),
- Pleasurable emotions (“Mmm… cheese”), and
- Positive reinforcement (“Cheese makes me feel good so I’m gonna get more cheese”).
They also determine our executive functioning abilities. That’s planning, problem solving, reasoning, etc. Lastly, they also regulate our memory.
Think about all the symptoms associated with ADHD: forgetfulness, impulsive decision-making, issues with planning and organization. It’s not surprising that people with ADHD are thought to have defective dopamine pathways.
Example: dopamine transporters.
A number of studies suggest that people with ADHD have lower levels of dopamine transporters. This video has a great animation explaining transporters. Basically, when one neuron releases dopamine, a neighboring neuron has dopamine receptors. These bind to the dopamine molecules and pass them along the pathway. The first neuron has dopamine transporters which then scoop up all the excess, unbound dopamine. For a while, it made sense that patients with ADHD would have too many transporters. This would lower the amount of dopamine getting passed along.
But in 2006, Dr. Nora Volkow studied 20 patients with ADHD who had never taken any kind of medication. She found that they actually had fewer functioning dopamine and transporters in their reward pathway:
In a 2009 article in the Journal of the American Medical Association, the same author found that in 53 people with ADHD, most had lower levels of both dopamine receptors and transporters. This tells us that ADHD is, of course, a lot more complicated than we think; it’s not a dopamine deficiency, but an imbalance.
The reward pathway and antsy-ness
If the reward pathway doesn’t function properly, it can cause major problems with motivation. This is likely why people with ADHD often find it extremely difficult to engage in activities they don’t find enjoyable. This isn’t all that surprising; most people find it easier to plan a trip to Disneyland than to balance their checkbook.
But here’s what’s so frustrating: many people with ADHD, myself included, find it extremely difficult to motivate themselves to do those boring tasks even if they’re essential to their long-term goals. They often prefer instant gratification, which would explain why I keep re-watching Downton Abbey instead of working on my PhD applications. This is also why one main recommendation of ADHD specialists is to break large tasks up into smaller chunks, hence the hourly to-do lists.
On a less fun note, the brains of drug addicts and substance abusers — the prime example of instant gratification — are known to have messed up dopamine pathways as well.
- Messed up serotonin.
There are also high levels of a chemical called serotonin, plus its receptors, in regions of the brain associated with dopamine pathways. You might already know that serotonin is generally involved in feelings of well-being and happiness.
Many studies link serotonin with dopamine production. An imbalance in this relationship is thought to be at the heart of disorders like depression, schizophrenia, Tourette’s, Parkinson’s, and — you guessed it — ADHD. Serotonin is thought to be related more to emotions and mood, rather than motivation. In people with ADHD, this comes out in problems with impulse control and aggression. This might sound familiar — we’ve all known at least one kid like this.
Turns out, drugs like Ritalin stimulate levels of serotonin in the brain. In fact, the antidepressant Prozac, known to boost serotonin levels, has also been shown to help with hyperactivity.
Fun fact: serotonin is synthesized from tryptophan, but unless you take 100% pure tryptophan tablets, simply eating food with tryptophan in it won’t increase your brain’s serotonin levels. That means your good mood on Thanksgiving is simply because you’re fat and happy, not because you’re actually boosting serotonin levels by eating obscene amounts of turkey. If only I could treat my ADHD with daily turkey sandwiches.
- Messed up norepinephrine.
The last of the trifecta is a chemical called norepinephrine. You might know it better as noradrenaline, which is the same as adrenaline, except that it’s produced in the brain instead of the adrenal gland on the kidneys.
Norepinephrine is generally involved in the fight-or-flight response: preparing the body for action. It’s also involved in stress and stage fright. You may be familiar with beta-blockers, which can be taken to reduce stress, nervousness, and performance anxiety. These block certain norepinephrine receptors. People with ADHD are thought to have a lower-than-normal level of norepinephrine, which might explain why when I take too much of my stimulant ADHD medication, I get crazy stressed out and my blood pressure skyrockets. It might also explain why I’m such an incredible public speaker.
Anyway. Let’s conclude by going back to one of the purposes of this blog: looking critically at scientific findings and stories. One giant thing you need to take away from this post is that this is circumstantial evidence. I’ve listed lots of ways my behavior seems to support what scientists think about ADHD. But I’ve never had my dopamine transporter levels checked out. I’ve never had a genetic test done to find out which ADHD markers I actually have. All I know is, I have all the symptoms and the medication works.
I take comfort in the fact that my kids, who I already know will be scatter-brained genius spider monkeys, will have access to more scientific, reliable testing for ADHD than I did.
In the meantime, I hope you learned a little more about ADHD from this post — and, perhaps, about yourself!