Comorbidity
The presence of two or more conditions in the same person, either at once or over a lifetime. In mental health it is the rule rather than the exception: anxiety with depression, ADHD with anxiety or addiction, autism with ADHD, trauma with substance use.
What drives it
Reminds you that one label rarely explains a person: conditions share causes, feed each other, and one can mask another. Useful for identification because the obvious problem may not be the driving one.
How it shows
Work
A colleague treated for anxiety who still struggles with organisation (untreated ADHD), or a high performer with burnout who is also drinking heavily. Interventions targeting one problem do not lift performance.
Relationships
Partners notice that 'fixing' one issue (stopping drinking, treating depression) reveals another underneath. Arguments about which problem is 'real' are common.
Self
You may recognise yourself in several descriptions and wonder which one is you. The useful question is which came first and which drives the others.
What tells it apart
HiTOP (dimensional model of psychopathology): Comorbidity counts separate diagnoses; HiTOP explains the overlap as shared underlying dimensions.
DSM-5-TR and ICD-11: Some comorbidity is real co-occurrence; some is created by categorical systems splitting one problem into several labels with overlapping criteria.
A test
When treatment of one problem does not produce the expected change, look for a second condition (often ADHD, trauma, substance use or a mood disorder) and ask for a fuller assessment rather than a stronger dose of the same approach.
Questions to carry
- When treating one problem brought no change, which other condition could be running alongside it?
- Which of my struggles do I explain with one word, and what else might be feeding it?
How strong the research is
strong
Where it comes from
Alvan Feinstein, 1970; US National Comorbidity Survey by Ronald Kessler and colleagues, 1994
Sources
- American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) (2013)
- Roman Kotov and colleagues, The Hierarchical Taxonomy of Psychopathology (HiTOP): A Dimensional Alternative to Traditional Nosologies (2017)