In recent years, the mental health and neurodivergence communities have made remarkable progress in recognising how certain conditions can overlap, mimic, or mask one another. Among the most frequently confused or conflated are complex PTSD (C-PTSD), autism, and ADHD.
Although these are three distinct conditions—each with unique diagnostic criteria and causes—they often share surface-level similarities that can lead to misdiagnosis or misunderstanding, particularly in adults who have lived undiagnosed for decades (American Psychiatric Association, 2022; Kessler et al., 2007).
This article explores their similarities and differences, the impact of overlapping symptoms, and the misunderstanding of suicidal ideation that can occur, especially when C-PTSD is mistaken for other mental health conditions like Bipolar Disorder.
The shared landscape — similarities across the three conditions
Although complex PTSD is trauma-related, and both autism and ADHD are neurodevelopmental, people with these conditions often share common challenges (Carter & Iversen, 2020; Anderson & Bramoullé, 2021).
Emotional dysregulation
All three conditions can involve difficulties in regulating emotional responses:
- C-PTSD — intense mood swings, emotional flashbacks, and reactivity to perceived threats (van der Kolk, 2014)
- Autism — shutdowns or meltdowns due to sensory or social overload (Au-Yeung et al., 2019)
- ADHD — impulsive outbursts, frustration intolerance, and difficulty calming down (Anderson & Bramoullé, 2021)
Executive function difficulties
Problems with memory, planning, time management, and task initiation are prevalent across all three diagnoses (Briere & Scott, 2014). These issues are often misread as laziness or defiance, when in fact they are rooted in neurological wiring or trauma.
Environmental sensitivity
- C-PTSD — heightened vigilance to signs of danger, often leading to exhaustion (van der Kolk, 2014)
- Autism — hypersensitivity to sound, light, smell, texture, or temperature (Au-Yeung et al., 2019)
- ADHD — distractibility due to low threshold for sensory input, though less often rooted in discomfort (Anderson & Bramoullé, 2021)
Social difficulties
Each condition may present with social withdrawal or miscommunication, though for very different reasons:
- C-PTSD — avoidance due to mistrust or fear of further harm (Briere & Scott, 2014)
- Autism — challenges in reading non-verbal cues, maintaining reciprocity, or masking (Au-Yeung et al., 2019)
- ADHD — speaking over others, missing subtle cues, or impulsively saying the wrong thing (Carter & Iversen, 2020)
Sleep disruption
Insomnia, night terrors, and disrupted sleep patterns are common. Whether it’s due to a hyperactive mind, a dysregulated nervous system, or a trauma-triggered nightmare—restful sleep often remains elusive (Maté, 2021).
Understanding the distinctions — where the conditions differ
While overlap can be confusing, it’s critical to identify what makes each condition unique (American Psychiatric Association, 2022; World Health Organization, 2019).
| Feature | Complex PTSD | Autism | ADHD |
|---|---|---|---|
| Cause | Results from chronic trauma (often developmental) | Inborn neurotype, usually genetic | Inborn neurotype, often with genetic and environmental factors |
| Key traits | Flashbacks, emotional dysregulation, shame, and disconnection | Sensory sensitivity, need for routine, difficulty with social norms | Inattention, hyperactivity, impulsivity |
| Onset | Emerges after sustained trauma | Present from early childhood | Present from early childhood |
| Identity challenges | Feelings of worthlessness, self-blame | Sense of identity may be strong or atypical | Identity may shift impulsively with context |
| Sensory differences | Trauma-based reactivity (hypervigilance) | Sensory processing differences central to diagnosis | Often reactive to stimulation, but not always sensory-sensitive |
| Authority and structure | May fear or avoid due to prior trauma | May resist or misunderstand social hierarchies | May reject authority impulsively or inattentively |
| Treatment approaches | EMDR, somatic therapy, trauma-focused approaches | Sensory supports, social coaching, autism-informed therapy | Medication, behavioural coaching, structured routines |
When ideation is misunderstood — the danger of conflating suicidal thoughts
One of the more distressing areas of misdiagnosis involves suicidal ideation. This is especially relevant for people with complex PTSD who may be mistakenly diagnosed with Bipolar Disorder, particularly Bipolar II (Archer & Kukucka, 2020).
There are two main types of suicidal ideation:
- Passive ideation — thoughts like “I wish I didn’t exist” or “Life is too hard,” without intent to act
- Active ideation — specific thoughts of ending one’s life, possibly including plans or means
People with C-PTSD often experience chronic passive ideation as a result of deep emotional pain, helplessness, or feeling disconnected from safety or support (Maté, 2021; van der Kolk, 2014). These thoughts can surface regularly—sometimes daily—and are more about longing for peace than an actual desire to die.
In contrast, Bipolar-related ideation, particularly during depressive episodes, tends to be more episodic and can escalate quickly to active suicidal planning. The impulsivity and intensity of Bipolar mood swings also increase risk during manic or hypomanic phases (American Psychiatric Association, 2022).
Misinterpreting C-PTSD passive ideation as Bipolar suicidal risk can lead to misguided treatment, such as prescribing mood stabilisers where trauma therapy would be more appropriate (Archer & Kukucka, 2020).
If you or someone you know is experiencing suicidal thoughts—passive or active—it’s crucial to seek support from trauma-informed professionals, especially those with experience in neurodivergence.
Diagnostic complexity — when it’s more than one
Many people live with more than one of these conditions. Autism and ADHD often co-occur (known as AuDHD), and either may coexist with trauma responses that meet the criteria for complex PTSD (Carter & Iversen, 2020; Anderson & Bramoullé, 2021).
Unfortunately, traditional diagnostic frameworks tend to focus on either/or instead of both/and. An autistic adult with C-PTSD may be told their shutdowns are “just depression.” Someone with ADHD and trauma may have their impulsivity mistaken for a personality disorder or Bipolar II.
This is why self-awareness, compassionate clinicians, and careful longitudinal observation are essential.
Moving forward — clarity and compassion
Understanding the shared struggles and distinct traits of complex PTSD, autism, and ADHD empowers individuals and clinicians alike to move away from rigid labels and toward tailored support.
If you’re wondering whether one or more of these conditions fits your lived experience, it’s not about getting a “label”—it’s about unlocking the right tools, environments, and therapies that help you thrive rather than survive.
Remember:
- Emotional dysregulation isn’t always trauma.
- Sensory overwhelm isn’t always ADHD.
- Suicidal ideation isn’t always Bipolar.
But whatever it is, it deserves to be heard, validated, and treated with care.
References
American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR). Washington, DC: Author.
Anderson, M., & Bramoullé, Y. (2021). Executive function deficits in ADHD and autism spectrum disorder: A meta-analytic comparison. Journal of Abnormal Child Psychology, 49(2), 211–226. https://doi.org/10.1007/s10802-020-00743-0
Archer, C., & Kukucka, J. (2020). Suicidal ideation in PTSD and complex PTSD: The role of emotion regulation and shame. European Journal of Psychotraumatology, 11(1), Article 1721143. https://doi.org/10.1080/20008198.2020.1721143
Au-Yeung, S. K., Bradley, L., Robertson, A. E., Shaw, R., Baron-Cohen, S., & Cassidy, S. (2019). Experience of mental health diagnosis and engagement with services: A qualitative exploration of autistic adults. Autism, 23(3), 918–930. https://doi.org/10.1177/1362361318785172
Briere, J., & Scott, C. (2014). Principles of trauma therapy: A guide to symptoms, evaluation, and treatment (2nd ed.). Sage.
Carter, L., & Iversen, P. (2020). The co-occurrence of ADHD and PTSD in adult populations: Implications for diagnosis and treatment. Journal of Attention Disorders, 24(3), 381–393. https://doi.org/10.1177/1087054718770010
Kessler, R. C., Amminger, G. P., Aguilar-Gaxiola, S., Alonso, J., Lee, S., & Üstün, T. B. (2007). Age of onset of mental disorders: A review of recent literature. Current Opinion in Psychiatry, 20(4), 359–364. https://doi.org/10.1097/YCO.0b013e32816ebc8c
Maté, G. (2021). The myth of normal: Trauma, illness and healing in a toxic culture. Penguin Random House.
Porges, S. W. (2011). The polyvagal theory: Neurophysiological foundations of emotions, attachment, communication, and self-regulation. W. W. Norton & Company.
van der Kolk, B. A. (2014). The body keeps the score: Brain, mind, and body in the healing of trauma. Penguin Books.
World Health Organization. (2019). International classification of diseases for mortality and morbidity statistics (11th ed.). https://icd.who.int/
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