Early cannabis use was a strong independent predictor of subclinical hypomania symptoms at age 16 | Research

The takeaway

In a cohort of 1,632 Danish children followed from age 11 to 16, early cannabis use (by age 15) was the strongest independent predictor of subclinical hypomania at age 16, with a 3-fold increased risk.

Child psychiatrists, adolescent health professionals, parents, and researchers studying bipolar disorder risk.

3.14x risk of subclinical hypomania at 16 with early cannabis use

What the researchers found

Cannabis use by age 15 was a strong independent predictor of self-reported subclinical hypomania at age 16 (RR 3.14, 95% CI 1.93-5.10), after adjusting for age 11 psychopathology and other precursors. Psychotic experiences at age 11 (RR 2.06) and emotional disorders (RR 1.77) also predicted age 16 hypomania. Subclinical hypomania at age 11 showed modest continuity with age 16 (RR 1.89).

Why it matters

Subclinical hypomania in adolescence may be an early marker of bipolar disorder risk. Finding that early cannabis use is the strongest modifiable predictor provides a potential intervention target.

The numbers in context

1,632 at age 11; 893 reassessed at age 16; cannabis by age 15 RR 3.14; psychotic experiences RR 2.06; emotional disorders RR 1.77; age 11 SHM → age 16 SHM RR 1.89

How the study worked

Longitudinal study from the Copenhagen Child Cohort 2000. 1,632 preadolescents were assessed for subclinical hypomania and clinical correlates at age 11 via semi-structured interviews. 893 were reassessed at age 16 with self-report (HCL-32). Cannabis use by age 15 was assessed at age 16.

What this study cannot tell us

Cannabis use assessed retrospectively at age 16 for use by age 15. Self-reported hypomania at age 16 may differ from interview-based assessment. Cannot determine whether cannabis caused hypomania or shared vulnerability explains both.

How to read the evidence

Large population-based longitudinal cohort with structured assessments, though self-report at age 16 and retrospective cannabis assessment are limitations.

When this study was published

Published in 2021.

The bigger picture

Cannabis use standing out as the strongest independent predictor of subclinical hypomania, even stronger than pre-existing psychotic experiences, adds to growing evidence that early cannabis use may specifically increase risk for bipolar spectrum pathology.

Questions still open

Does preventing early cannabis use reduce bipolar disorder risk? Is the association specific to cannabis or would other substances show similar patterns? Could subclinical hypomania at 16 predict full bipolar disorder later?

Common questions

Can cannabis trigger early signs of bipolar disorder?

This study found early cannabis use was the strongest independent predictor of subclinical hypomania at age 16, with a 3-fold increased risk. However, whether cannabis directly triggers these symptoms or shares underlying vulnerability factors is not established.

What is subclinical hypomania?

Subclinical hypomania includes symptoms like elevated mood, increased energy, and reduced need for sleep that are common in adolescence but may be early markers of bipolar disorder risk when persistent or severe.

Read the original research

Precursors of self-reported subclinical hypomania in adolescence: A longitudinal general population study.

PloS one, 16(6), e0253507

View on PubMed ↗Publisher’s paper ↗

Citation

Nielsen, Louise Gunhard; Køster Rimvall, Martin; Van Os, Jim; Verhulst, Frank; Rask, Charlotte Ulrikka; Skovgaard, Anne Mette; Olsen, Else Marie; Jeppesen, Pia. (2021). Precursors of self-reported subclinical hypomania in adolescence: A longitudinal general population study.. PloS one, 16(6), e0253507. https://doi.org/10.1371/journal.pone.0253507