Remembering Jules Angst, Bipolar Pioneer

The psychiatrist who split mood disorders into bipolar and unipolar went on to argue that they are part of a single spectrum

Splitting Unipolar and Bipolar

Jules Angst died in May 2026. He was born in 1926, the same year that Emil Kraepelin died, and he lived long enough to undo Kraepelin’s work and then put it back together.

Kraepelin was the first psychiatrist to separate schizophrenia from manic-depression. He spent the rest of his life trying to split manic-depression further, into its bipolar and unipolar sides, but was unable to, concluding:

• “This classification, apparently so simple, really encounters manifold difficulties.” — Emil Kraepelin, Manic Depressive Illness

Angst picked up that cause in the 1960s. Along with Carlo Perris, he recognized that the two mood disorders differ in their family histories and response to treatment. Their proposed division entered DSM-III in 1980, replacing Kraepelin’s manic depression with bipolar and unipolar mood disorders.

Bringing Them Back Together

Within months of DSM-III’s publication, psychiatrists wrote letters decrying the split as premature, pointing out similarities between unipolar and bipolar. Both responded to lithium; had similar EEG findings; and overlapped in family histories and symptoms (eg, mixed states).

Angst saw both sides of the argument, and spent the rest of his career filling in the gaps in the “bipolar spectrum” that connected the two sides — the mixed features, cyclical depressions, and brief hypomanias that don’t cross the threshold for DSM-III bipolar disorder, but aren’t quite unipolar either.

With each new edition of the DSM, the manual gradually adopted Angst’s new perspective, first with bipolar II in DSM-IV (1994), and later with a fuller spectrum in DSM-5 (2013):

Mood disorders occur occur on a spectrum, from bipolar I to pure depression, but they can also be boxed into categories as shown above. Where we draw the line between unipolar and bipolar is arbitrary. DSM-5 draws it at the red/blue divide at top, but Angst’s research pointed to the orange/blue divide at bottom.

Angst may be the only psychiatrist who revolutionized the DSM twice, from the categorical split of DSM-III to the spectrum concept of DSM-5. David Kupfer, Chair of DSM-5, echoed Angst when he wrote that depression and bipolar are part of “a continuum, with variable expressions of vulnerability to hypomania or mania.”

The distinction is not just theoretical. In his BRIDGE study, Angst and colleagues showed that the risk of mood switching on an antidepressant rises with the duration of past hypomania. In this graph, only the red-shaded area reflects DSM-5 bipolar disorder, but the risk is there for the orange-tinted spectrum patients as well.

The Bipolar-Normal Continuum

Angst also recognized that hypomania occurred on a continuum, with varying degrees of intensity from normal to bipolar and no clear dividing line between them. He followed two cohorts for over five decades: a hospitalized affective disorder cohort and a normal community sample. He found hypomanic symptoms in both groups, and could not find a clear dividing line between the bipolars and the “normals.”

His paper Are hypomanics the happier normals? describes people with frequent hypomania but no depression. DSM doesn’t recognize this type, so they were grouped in the “normal” community sample, but Angst saw problems. Their lives were not so chipper as the hypomanic stereotype suggests. They were irritable and impulsive, with insomnia, substance use, and binge eating.

Other Contributions

Angst worked into his 90s. His papers are richly detailed and practical. Many have multiple findings that could be plucked out as papers on their own, like the spectrum of antidepressant response above, which was buried in a table of the larger BRIDGE study.

• Angst provided the statistical backbone for the first international lithium prophylaxis data, defending Mogens Schou’s before-and-after evidence against critics who wanted randomized trials first. Lithium later became the only mood stabilizer to meet a strict four-part efficacy standard: acute mania, acute depression, and prevention of both.
• He identified Recurrent Brief Depression and showed that its overlap with major depression signals a subgroup at sharply higher suicide-attempt risk.
• He developed the Hypomania Checklist (HCL-32), a widely used bipolarity screening tool, later refined into the HCL-33.
• His BRIDGE study removed the 4-day duration cutoff for hypomania, showing that people with shorter durations had bipolar features like mixed states, antidepressant-induced mania, and family loading for bipolar disorder.
• In one of the BRIDGE papers, Angst showed that the long-recognized link between mood disorders and alcohol use disorders was not due to depression. Rather, it was entirely explained by mixed features. When patients with those impulsive, agitated, anxious symptoms were removed from the BRIDGE sample, the association disappeared.

Legacy

Angst kept revising his own conclusions as new data arrived. His journey shapes today’s debates over where unipolar depression ends and bipolarity begins.

If you’ve ever struggled to figure out if a patient had bipolar or unipolar, take heart. Angst and Kraepelin couldn’t find a clean line either. The Bipolarity Index helps clarify the ambiguity.

—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report

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