Of course, there are some symptoms of ADHD which are widely known. These symptoms are very closely associated with ADHD, and they are the ones that clinicians will look for first when determining whether a patient meets the criteria for a diagnosis.

However, there are other symptoms that aren't as familiar. These are the types of symptoms that often fly under the radar, so to speak, which can potentially lead to trouble in the long run. Someone who experiences less-common symptoms might not suspect that they have ADHD, which means they may not seek out the diagnosis and treatment which could significantly improve their life.

The Most Common Symptoms of ADHD

ADHD's most common symptoms are actually mentioned right in the name. ADHD stands for attention-deficit/hyperactivity disorder, so it should come as no surprise that inattention and hyperactivity are considered to be the hallmarks of the condition.

In fact, it goes further than that. Inattention and hyperactivity are actually the names used for two of the three types of ADHD. The third is combined type ADHD, which includes both inattentive and hyperactive behaviors.

Inattention and hyperactivity are very broad terms. When someone is evaluated for ADHD, their clinician will look for specific examples of these symptoms in their day-to-day life.

Inattentive ADHD

When someone with ADHD mostly struggles with paying attention and maintaining focus, they may be diagnosed as having a predominantly inattentive presentation of the disorder. Here's are some of the most common examples of how inattentive symptoms can manifest as ADHD behaviors:

  • Difficulty maintaining attention
  • Easily distracted by external stimuli
  • Struggling to follow detailed instructions
  • Not listening when spoken to
  • Avoiding tasks that require sustained mental effort
  • Making careless mistakes
  • Misplacing things
  • Disorganization
  • Forgetfulness in daily activities

Hyperactive-impulsive ADHD

ADHD hyperactivity is typically accompanied by impulsivity, which is why people with the disorder who mostly struggle in these areas may be diagnosed as having a predominantly hyperactive-impulsive presentation of the disorder. Here's are some of the most common examples of how hyperactive and impulsive symptoms can manifest as ADHD behaviors:

  • Moving almost constantly as if “driven by a motor”
  • Struggling to remain still or seated
  • Fidgeting and squirming
  • Running, climbing, and jumping when not permitted
  • Difficulty remaining engaged in quiet activities
  • Talking excessively and frequently interrupting others
  • Blurting out answers before being called on
  • Not taking turns in games and activities
  • Demonstrating impatience when told to wait
  • Taking risky actions without thinking

Surprising Symptoms of ADHD

Some of the not-so-common symptoms of ADHD are the ones which aren't as obvious to others. While it's typically easy to notice when someone is hyperactive or distracted, there are symptoms of ADHD which are harder to detect. On top of that, the less-common symptoms of ADHD aren't as strongly associated with the disorder, so they could potentially lead to a misdiagnosis. The following are some of the rarer symptoms of ADHD.


Hyperfocusing occurs when someone becomes so fixated on an activity that they can’t be pulled away easily. This symptom is surprising since it's the opposite of what many people expect of someone with ADHD, which is a lack of focus. However, hyperfocus is actually another possible outcome of the dysregulated attention system that people with ADHD have. It usually occurs when someone with ADHD is doing someone that they enjoy (as opposed to homework, chores, etc.), but not all people with ADHD experience periods of hyperfocus.

Sleep issues

ADHD may make it difficult to get a good night's rest. About 25% to 50% of people with ADHD have sleep problems, which can manifest in a variety of ways. For example, people with ADHD could have trouble falling asleep at night due to mental restlessness. Others may have a hard time waking up in the morning or experience sudden drowsiness during the day. Sleep issues like obstructive sleep apnea, jaw clenching, and teeth grinding have also been linked to ADHD.

Mood swings

Some people with ADHD experience rapid changes in mood. Someone with the disorder might have strong emotional reactions to feelings of disappointment, frustration, or anger. In addition, irritability can be a potential side effect of some stimulant medications for ADHD. Anxiety and depression are relatively common among those with ADHD, and mood swings are a possible symptom of both of these conditions.

Not sure if you have ADHD? Even if you have some of the most common symptoms of the disorder, you may want to consider whether you have some less-common symptoms of ADHD that you hadn't considered before. If you'd like more information, schedule a consultation with one of our licensed clinicians at Done.