Each page covers one condition properly: what it actually is and what it feels like, what causes it, how common it really is and in whom, and how it's diagnosed — followed by the specific variants with a replicated link to it, and, where the research supports it, how genetics can change the way a medicine behaves.
Written in two registers so one page serves both readers: plain language first, then a clinical detail section with the precise terminology, effect sizes and diagnostic thresholds. Every claim is sourced from freely-available published research and cited on the page, so you can check us — or hand the page to your doctor. 385 conditions so far, growing continuously, and free to reuse with attribution (CC BY 4.0).
13 results in Behavioural
PTSD has been harder to map genetically than most psychiatric disorders. A 2024 study of more than 1.2 million people found 95 loci, 80 of them new, and 43 likely causal genes. 13 of the positions it reports are in this catalogue.
Read more → Behavioural206 variants shared across alcohol, cannabis, opioid, and tobacco use disorders — from the largest cross-substance genetic study to date, which found the same genes keep showing up no matter which substance is involved.
Read more → BehaviouralGenetic risk for insomnia runs, in the same population, alongside genetic risk for major depressive disorder and type 2 diabetes — evidence that sleeplessness shares real biology with conditions far outside sleep itself.
Read more → BehaviouralThe largest genetic study of drinking to date, in 274,424 people, found that how much someone drinks and whether they develop a use disorder are related but genetically separable — heavy drinking is a risk factor, not a sufficient cause.
Read more → BehaviouralNot a page about autism, and not a page about schizophrenia — a page about the genetic overlap between the two. Thirty variants, twenty-eight of which sit within one crowded region on chromosome 6 — the same MHC/HLA region already known as schizophrenia's single strongest signal — which likely means one real association is being counted many times over, not thirty separate findings.
Read more → BehaviouralDepression and alcohol dependence often occur together, and this page is specifically about the genetics of that co-occurrence — a different question from either condition alone. The one variant found here was significant only in African American participants; no association reached significance in the European American participants in the same study.
Read more → BehaviouralAnxiety disorders are usually studied one at a time. A meta-analysis of over 18,000 people pooled several of them together to ask whether a shared genetic signal exists across the category, and found one — the strongest hit in its case-control analysis is the variant on this page.
Read more → BehaviouralFour population-scale studies, from 161,460 to 807,553 people, measured self-reported or broadly defined depression rather than a clinical diagnosis — a related but distinct question from the Major Depressive Disorder page this site already has.
Read more → BehaviouralA study of how often people nap found its way to the exact receptors a licensed class of insomnia drugs already targets. It also found that napping more often looks like a cause of higher blood pressure rather than merely a companion of it — which, on this site, makes it the exception rather than the rule.
Read more → BehaviouralThe clearest published answer to "how many genes?" for any psychiatric condition: about 8,300 of them, together explaining at least a third of the liability. Which is also why no single one of the fourteen on this page tells you anything.
Read more → BehaviouralOne of the clearest demonstrations of a rule that governs all of this: the more people they looked at, the smaller the effect got. It started at 1.31 and finished at 1.17 — and the second number is the honest one.
Read more → BehaviouralOne of the most heritable common conditions there is — and one of the least predictable from a genome. Twin studies put the inherited share around 70-80%, yet the first reliable common variants were only found in 2019, and each one moves the odds by a few percent. This page is about why both of those are true at the same time.
Read more → BehaviouralGenetics has little to say about whether someone starts smoking and quite a lot to say about how heavily they smoke once they do — and, unusually, something practical about which quitting medicine is likely to work better.
Read more →One diagnosed condition or measurable trait covered properly: what it actually is, what causes it, how common it is, how it is diagnosed, and the specific variants with a replicated link to it — every claim sourced from published research.
No. Every page here is informational, not a diagnosis. A result should be discussed with a doctor or a licensed genetic counselor, never acted on alone.
Because they are not disorders. Height, ABO blood group and a handful of others describe a measurable characteristic with nothing to diagnose — "Trait" says so plainly instead of implying a disease that is not one.
Only after a replicated association in published research, verified against the primary study rather than a gene name or a marketing claim — the same discipline the variant pages themselves follow.