Major Depressive disorder is the most common mental condition in adolescents, running about 10-15%. That's 3-5 in every class of 30 students. Attention Deficit Hyperactivity Disorder (ADHD) is the third most common mental health disorder, after Depression and Generalized Anxiety Disorder (GAD). Significant ADHD is found in 5-10% of the general public. In adults with ADHD, depression is the most likely condition to be riding in the side-car.

ADHD is more than just daydreaming, difficulty concentrating or hyperactivity. Our data suggests that other traits may be clues that ADHD is lurking:
Messy desk, backpack, school notes
Easily bored, resistant to low reward tasks
Difficulty turning off your thoughts at night.
MDD prevalence in adolescent girls is about 2–3 times higher than in boys, likely due to the perfect storm of:
hormones
the pressure-cooker of girl-cliques that often ends with social exclusion
the evolutionary drive to get their genes into the next generation. (females wanting to be attractive to mates existed long before modern media).
ADHD and MDD combined
Studies show that ADHD increases the risk of developing MDD. Several factors may contribute to this relationship.
As adolescents with ADHD move up through the academic gears, from reading and writing to math and science, the inability to keep up with their peers exerts a strong downward pressure on the social ladder. If they are not sporty, they may soon find themselves on the bottom rung, with the group for whom there are no entry criteria. That's practically a death sentence for self-esteem.
Being lower in the social/ academic order, for a number of reasons, puts you in the presence of classmates who are more likely to have low self-esteem, poor marks, skip class, use cannabis and have earlier sexual interactions.
On the other hand, feeling sad, tired and lacking motivation, makes attending to the details of school more difficult.
Anxiety, often holds hands with depression. Losing friends and not meeting deadlines is stressful. Anxiety makes concentration more difficult.
In the other direction, studies show that nearly 60% of individuals with ADHD reported experiencing high levels of social and academic failure, which can trigger low self-esteem and depression.
ADHD, MDD and Substance Use
If you mix ADHD-driven failure with low self-esteem, adverse events, and a vulnerability to addiction, you can get the most deadly of all combinations... self-sabotage. In the worst case scenario, you have someone who needs help, but rejects it. I asked a patient once why she kept using Fentanyl after she had alredy OD'd twice. She said, "because I hate myself and I want to die."
ADHD and MDD symptoms overlap, sort of.
ADHD and MDD are very different. It should not be difficult to tell them apart.
Both can cause difficulty concentrating. But there's one big difference.
MDD is cyclical, it comes and goes. Difficulty concentrating in MDD is temporary; it aligns with the worst symptoms of depression. In ADHD, the difficulty concentrating is chronic. It has been there since childhood, and it's there through good and bad.
Irritability and impatience are not a symptom of low mood. They are a symptom of fluctuating mood, what we call mood dysregulation.
Mood dysregulation may be seen in ADHD and MDD, but it's a completely different disorder, that often co-occurs. Mood dysregulation is a layer of neurobiological dysfunction that stacks on top of ADHD, MDD, substance use etc.
Diagnostic Challenges
Having a sensitive ear and recognizing the difference in these patient stories can assist healthcare providers in differentiating between the two disorders, ensuring comprehensive treatment. Healthcare providers should undertake thorough evaluations that include:
Comprehensive History - Listening to the story first, including family, childhood and personal histories, can shed light on patterns and factors relating to both conditions. If you ask about other people in the family you will often see one parent had predominantly ADHD traits and the other had traits of Depression or Anxiety.
Standardized Assessments: Utilizing specific questionnaires and scales for ADHD and MDD can aid in increasing diagnostic precision.
Input from Family: It is often said that engaging with parents and teachers can provide essential insights, but that's not always true. Often one or the other is in denial, or they disagree because they see completely different versions of the child, I find it more effective to engage the family and leave the teachers out of it.
Treatment Approaches
Treating ADHD and MDD simultaneously requires a comprehensive personalized approach.
As mentioned in our podcast, most clinicians either miss the ADHD completely or treat the MDD first. Our data suggests that the better approach is to treat the ADHD first, because that often leads to a significant improvement in mood.
Stimulants first: Medications such as long-acting methylphenidate and amphetamines are typically prescribed for ADHD. Research indicates that about 70-80% of individuals with ADHD show improvement in focus and behavior with these medications.
Antidepressants, if necessary: Selective Serotonin Re-uptake Inhibitors (SSRIs) can help manage depression. However, healthcare providers must carefully track changes, as some stimulant medications may worsen anxiety or depressive symptoms.
Executive Skill Coaching: is more effective than therapy for treating ADHD, because ADHD patients tend to forget instructions and almost never do the homework necessary to benefit from CBT.
Cognitive Behavioral Therapy (CBT): Our data suggests that CBT is much more effective for reducing the distress and depressive symptoms. It has little effect on cognitive or executive deficits and even less on impulsivity or hyperactivity
Mindfulness-Based Interventions: Mindfulness practices are also not particularly helpful for cognitive deficits, but they are very effective at decreasing distress, improving emotional regulation and increasing self esteem.
Physical Activity is the Wonder Drug: Regular exercise has shown benefits for mood and cognitive functions. Research suggests even short bursts of activity can boost dopamine and serotonin enough to extend focus through an otherwise boring task.
Healthy Nutrition: Consuming a balanced diet rich in fruits, vegetables, and whole grains supports neurotransmitter efficiency and overall brain health.
To Sleep, perchance to dream: Leaving your device in the other room and prioritizing sleep is not optional. Deep sleep is essential for focus, memory and executive function. It also improves mood and decreases impulsivity.

Insights for a Brighter Future
The link between ADHD and Major Depressive Disorder involves complex interactions among shared symptoms, biological factors, and life experiences. Recognizing and understanding these connections is crucial.
Utilizing a customized blend of medication, psychotherapy, and lifestyle changes, individuals facing these challenges can develop pathways toward better mental health. Clinician compassion and support become essential in promoting resilience and hope.
By shedding stigma, and expanding our awarensss of the science, we empower individuals to meet their full potential in life.
Excellent article. Thank you. I finally feel understood. In my experience as a woman, ADHD & MDD overlap and the treatment approaches suggested within the article are valid. Recent CBT success was definitely impacted by my inability to do the homework. Time to get back on the treatment horse.