Psychotic Spectrum Risk and Your Genetics

Written by Scott Peeples, BS Biomedical Sciences · ExomeDNA Founder Reviewed by ExomeDNA Editorial Process · [/methodology/editorial-process] Last reviewed: May 2026

This page contains general information only. For personal health decisions, consult a qualified clinician.

Psychotic spectrum risk is a measure of the inherited component of probability for developing schizophrenia or bipolar disorder — two serious psychiatric conditions that share more genetic architecture than their distinct clinical presentations might suggest.^[¹] Twin studies estimate heritability at roughly 80% for schizophrenia and 60–85% for bipolar disorder, yet most people who carry elevated risk variants never develop either condition. Below: how overlapping genetic signals connect these two conditions, the key genes implicated across both, and what current research suggests about the modest but real role that modifiable factors play.

What is psychotic spectrum risk?

Psychotic spectrum risk refers to the portion of an individual's probability of developing schizophrenia (ICD-10: F20) or bipolar disorder (ICD-10: F31) that traces to inherited genetic variants. Both conditions involve disruptions to mood, thought, or perception, and genome-wide studies have confirmed that the two conditions share a large fraction of their underlying genetic signal. Lifetime population risk is roughly 0.7% for schizophrenia and approximately 2% for bipolar disorder; elevated polygenic scores shift these baselines modestly upward, not to certainty.

The concept of a "psychotic spectrum" reflects a scientific observation, not a single disease category. Schizophrenia and bipolar disorder sit at different points along a continuum of psychosis-related genetic liability. People with one condition often carry genetic risk for the other, and family studies show that relatives of someone with schizophrenia face modestly elevated risk of bipolar disorder, and vice versa. Understanding this shared architecture is one of the more consequential recent findings in psychiatric genetics.

The genetics behind psychotic spectrum risk

The genetic architecture of psychotic spectrum risk is highly polygenic — hundreds of common variants each contribute a small fraction of the total inherited signal. No single gene causes either schizophrenia or bipolar disorder; instead, the cumulative burden of risk variants across the genome determines statistical positioning relative to population averages.

A large cross-diagnostic genome-wide study combining data from nearly 40,000 individuals identified six genome-wide significant loci shared between schizophrenia and bipolar disorder, including CACNA1C, IFI44L, TRANK1, MAD1L1, and PIK3C2A.^[¹] These genes represent some of the most replicated signals in cross-psychiatric genetics. A separate study examining the 7p22.3 chromosomal region — home to the MAD1L1 gene — identified specific variants (rs1637749 and rs3800908) associated with both conditions in an East Asian cohort of more than 64,000 individuals combined across discovery and replication samples, with MAD1L1 expression in blood correlating with the risk alleles.^[²]

CACNA1C (calcium voltage-gated channel subunit alpha-1C) encodes the alpha-1C subunit of the L-type voltage-gated calcium channel, known as Cav1.2. This channel controls how calcium enters neurons in response to electrical activity. Calcium influx through Cav1.2 regulates downstream gene expression via the CREB and NFAT signaling pathways — cascades involved in synaptic plasticity, long-term potentiation, and neuronal survival. CACNA1C is one of the most consistently replicated cross-psychiatric GWAS signals, with associations spanning schizophrenia, bipolar disorder, and major depression. Some mood-stabilizing medications act on calcium channel signaling, though the therapeutic relevance of specific CACNA1C variants to individual drug response is not established.

MAD1L1 (mitotic arrest deficient 1-like 1) is a component of the spindle assembly checkpoint — the cellular machinery that prevents chromosomes from separating prematurely during cell division. MAD1L1 is expressed in developing neurons, and variants near this gene have appeared in multiple independent GWAS of both schizophrenia and bipolar disorder. The 7p22.3 association study found that risk SNPs correlated with reduced MAD1L1 expression in blood samples, consistent with a gene-regulatory mechanism rather than a coding change.^[²]

TRANK1 (tetratricopeptide repeat and ankyrin repeat 1) contains structural protein-interaction domains and has appeared repeatedly in bipolar disorder GWAS. Its precise function in neural tissue is not yet fully characterized, but its recurrent appearance across independent studies makes it one of the more credible bipolar risk genes in the current literature.

IFI44 and IFI44L (interferon-induced protein 44 and its paralog IFI44L) are induced by type I and type II interferons and are components of the antiviral immune response. Both genes are upregulated during inflammatory states. Their presence among cross-diagnostic psychiatric risk loci supports a neuroinflammation hypothesis — the idea that immune dysregulation during early brain development or in response to environmental triggers may contribute to psychosis-spectrum vulnerability in genetically predisposed individuals.

ADGRL4 (adhesion G protein-coupled receptor L4, also known as latrophilin 4) belongs to a receptor family involved in cell adhesion and synaptogenesis. ADGRL4 signals through adenylate cyclase-activating pathways and has been implicated in the formation and maintenance of synaptic connections during neurodevelopment.

PIK3C2A (phosphatidylinositol 4-phosphate 3-kinase C2-alpha) is a class II phosphoinositide 3-kinase involved in endocytosis and vesicle trafficking — processes central to neurotransmitter recycling at synapses. It was identified as a novel locus in the cross-diagnostic GWAS by Ruderfer et al. 2014.^[¹]

TTLL6 (tubulin tyrosine ligase-like 6) adds glutamate chains to tubulin, a modification called polyglutamylation that is important for cilia and intracellular transport. The connection to psychiatric risk through this gene is less mechanistically characterized than CACNA1C or MAD1L1 and remains under active investigation.

6 genome-wide significant loci shared between schizophrenia and bipolar disorder were identified in a cross-diagnostic study of nearly 40,000 individuals — including CACNA1C, IFI44L, TRANK1, MAD1L1, and PIK3C2A — confirming substantial shared genetic architecture across the psychotic spectrum.^[¹]

What the research says

Research base: Moderate. The genetic overlap between schizophrenia and bipolar disorder is one of the best-replicated findings in psychiatric genetics, supported by large-scale consortium studies across diverse populations. Cross-diagnostic GWAS studies combining tens of thousands of cases and controls have consistently identified overlapping risk loci.^[¹] Independent replication in East Asian cohorts further strengthens the evidence for specific loci such as the 7p22.3 region containing MAD1L1.^[²]

The genetic correlation between schizophrenia and bipolar disorder is estimated at approximately 0.7 on a scale of 0 to 1, meaning these two conditions share the majority of their common-variant genetic signal. This high correlation challenges the traditional view of schizophrenia and bipolar disorder as biologically distinct diseases and has led to proposals for dimensional rather than categorical approaches to psychiatric classification.

That said, polygenic scores for psychotic spectrum risk explain only a modest fraction of the total variance in who develops these conditions. Even at extreme ends of the risk score distribution, absolute lifetime risk shifts modestly above population baselines — it does not approach certainty. Environmental contributors — including perinatal complications, cannabis exposure during adolescence, childhood adversity, and severe psychosocial stress — account for a substantial portion of risk that genetics alone does not capture.

More than 64,000 individuals across discovery and replication cohorts were included in the analysis that confirmed the 7p22.3 locus (near MAD1L1) as a shared risk signal for both schizophrenia and bipolar disorder, with risk alleles correlating with reduced MAD1L1 expression.^[²]

Current polygenic risk scores for schizophrenia and bipolar disorder are research-grade tools with limited clinical utility for individual prediction. A score indicating statistically elevated risk does not mean a person will develop either condition; most people with elevated scores do not. The primary value of this genetic information lies in contextual awareness, not clinical prediction.

For methodology details, see the ExomeDNA methodology page.

How psychotic spectrum risk affects you

Understanding your genetic positioning on the psychotic spectrum has different implications depending on family and personal history.

For most people, an elevated psychotic spectrum score is a statistical observation about population-level risk, not an individual forecast. The lifetime risk for schizophrenia in the general population is approximately 0.7%; for bipolar disorder, approximately 2%. Carrying more risk variants shifts your statistical baseline modestly above these figures — but the absolute shift is small, and most people with elevated polygenic scores never develop either condition.

For people with a family history of schizophrenia or bipolar disorder, genetic risk adds context to an already-elevated baseline. First-degree relatives of someone with schizophrenia face approximately 10% lifetime risk; for identical twins, concordance is around 50% — well below the 100% that pure genetic determinism would predict. The gap between 50% and 100% concordance in identical twins, who share all their DNA, is strong evidence that environmental and developmental factors play a large and irreducible role.

The most actionable use of psychotic spectrum genetic information is not individual prediction. It is: awareness of family history patterns, attention to early warning signs in adolescence and young adulthood (the typical window for psychosis onset), and informed conversations with clinicians when symptoms arise. Genetics can provide context; it cannot replace clinical assessment.

Working with your psychotic spectrum result

The following steps reflect evidence-supported practices relevant to people who carry elevated genetic risk for psychotic spectrum conditions. This list is informational and is not a substitute for professional clinical evaluation.

1. Know the early warning signs. The typical onset window for schizophrenia and bipolar disorder is late adolescence through the mid-twenties. Prodromal signs — changes in sleep, social withdrawal, unusual thinking, elevated or depressed mood lasting weeks — warrant prompt clinical evaluation, regardless of genetic profile.
2. Seek early help if symptoms arise. Early intervention after a first psychotic or manic episode is associated with better long-term outcomes. Genetic risk scores do not determine when or whether symptoms will appear; clinical presentation, not PRS, drives care decisions.
3. Limit cannabis use, especially in adolescence. Heavy cannabis use during adolescence appears to interact with genetic vulnerability to psychosis onset, and this is one of the better-characterized modifiable risk factors for schizophrenia-spectrum conditions. The interaction appears strongest in people with high genetic loading.
4. Prioritize sleep regularity. Disrupted sleep is both a prodromal feature and a potential trigger for mood and psychotic episodes in genetically susceptible individuals. Consistent sleep-wake timing is a low-risk, evidence-adjacent protective practice.
5. Manage sustained psychosocial stress. Severe, chronic psychosocial stress — particularly in early life — interacts with genetic predisposition for psychiatric outcomes. Stress-reduction approaches (therapy, social support, structured routines) are reasonable complements to clinical care.
6. Discuss family history with a clinician. Family history remains a stronger individual risk predictor than PRS for most people. A clinician familiar with psychiatric risk can integrate genetic results with family history and current symptoms into a coherent picture.
7. Contextualize the score carefully. An elevated polygenic score is not a clinical classification, a prediction, or a sentence. It is a statistical descriptor of inherited risk relative to population averages. Most people with elevated scores live without developing either schizophrenia or bipolar disorder.

Related traits and genes

The psychotic spectrum sits within a broader cluster of genetically overlapping brain and mental health traits. Several share genes or chromosomal loci with this trait.

Within Brain & Mental Health: Genetic risk for schizophrenia and bipolar disorder overlaps substantially with Adult ADHD genetic risk, Depression genetic risk, and Anxiety sensitivity. These conditions share portions of their polygenic architecture, consistent with a transdiagnostic view of psychiatric genetics.

Cross-category links: The neuroinflammation angle from IFI44 and IFI44L connects to Chronic inflammation genetic risk. The calcium-channel biology of CACNA1C intersects with Cardiovascular rhythm genetic factors, as Cav1.2 channels are expressed in both cardiac and neural tissue.

Frequently asked questions

Is psychotic spectrum risk the same as having schizophrenia or bipolar disorder? No. Psychotic spectrum risk is a measure of inherited genetic predisposition — how your variant profile compares to population averages. It is not a clinical classification of either condition. Most people with elevated genetic scores never develop schizophrenia or bipolar disorder.

Why does one score cover both schizophrenia and bipolar disorder? Because the two conditions share a large fraction of their underlying genetic signal. Genome-wide studies have found a genetic correlation of approximately 0.7 between schizophrenia and bipolar disorder, meaning most of the common variants that elevate risk for one also elevate risk for the other. A cross-diagnostic score captures this shared architecture more completely than two separate scores would for many variants.

What does a higher score actually mean for my lifetime risk? It means your genetic baseline is statistically above average for the population. Lifetime population risk for schizophrenia is roughly 0.7% and for bipolar disorder roughly 2%. An elevated score shifts these baselines modestly upward — it does not approach certainty or even double-digit percentages for most people. Most individuals with elevated scores do not develop either condition.

Can cannabis use increase my risk if I have this genetic profile? Research suggests that heavy cannabis use during adolescence appears to interact with genetic vulnerability for psychosis-spectrum conditions. People with higher genetic loading may face a greater increase in risk from cannabis exposure than people with lower loading. Limiting use — especially during adolescence and early adulthood — is one of the few modifiable factors with reasonable supporting evidence.

Should I be worried if a close relative has schizophrenia or bipolar disorder? Family history is a meaningful risk factor that operates partly through shared genetics and partly through shared environment. If a first-degree relative is affected, lifetime risk rises to approximately 10% — higher than the population baseline, but still meaning that roughly 90% of first-degree relatives do not develop the condition. This is a useful conversation to have with a clinician rather than something to manage through genetic scores alone.

Is this genetic information useful for medication decisions? Some calcium-channel-targeting mood stabilizers act on pathways relevant to CACNA1C, but the clinical relevance of specific CACNA1C variants to individual drug response is not established by current evidence. Pharmacogenomic testing for psychiatric medications is an active research area; consult a psychiatrist or clinical pharmacogeneticist rather than relying on a polygenic risk score for medication decisions.

References

1. Ruderfer DM, Fanous AH, Ripke S, McQuillin A, Amdur RL, et al. (2014). Polygenic dissection of clinical dimensions of bipolar disorder and schizophrenia. Molecular Psychiatry, 19, 1017–1024. PMID: 24280982.
2. Li W, et al. (2021). Identification of a risk locus at 7p22.3 for schizophrenia and bipolar disorder. Frontiers in Genetics, 12, 735372. PMID: 34976021.

Data sources:

• GWAS Catalog (NHGRI-EBI, accessed 2026-05-29)
• Open Targets Platform (CC0 1.0, accessed 2026-05-29)
• ClinVar (NCBI, accessed 2026-05-29) — entries at ≥2-star review status
• ClinGen Gene-Disease Validity (CC0 1.0, accessed 2026-05-29)

ExomeDNA genetic results are for wellness and educational purposes only. Consult a clinician for personalized health guidance.