Hyperthermic temperament may affect 4-5% of the population

by David N. Osser, MD

Current estimates are that 4% to 5% of the population is at risk for a disorder on the bipolar spectrum. Among the patients in the so-called soft portion of that spectrum are those with a disturbance of temperament in the direction of hypomania.

The concept of temperament is a product of German nosological research from a century ago starting with Kraepelin. In the US, the concept has been championed by Hagop Akiskal, MD and his colleagues. Akiskal is now the editor emeritus of the Journal of Affective Disorders. The notion of depressive temperament has been incorporated into DSM-5 nosology in the form of “persistent depressive disorder” (previously called dysthymia). The other pole was called hyperthymia by the Germans. DSM committees have considered adding hyperthymia but have not done so. The research base on it is still, to many, unconvincing. However, it seems that in clinical practice one encounters individuals who have chronic low-grade hypomanic symptoms—high energy, need for less sleep than others, chronic optimism, chronic risk taking. These individuals can be prone to major depressions and can become severely suicidal.

Akiskal and colleagues have been describing these patients for almost 40 years. Their research criteria for hyperthymic temperament include onset before age 21, habitual sleep of less than 6 hours even on weekends, excessive use of denial, and traits (described originally by Schneider et al) that include being overoptimistic, self-assured, grandiose, overtalkative, warm and people-seeking, uninhibited, promiscuous, and meddlesome (1). Neurobiological studies have suggested the individuals have dopaminergic dysregulation (2),

Treatment issues have focused on what medications to use when hyperthymic individuals become depressed. The studies have all been uncontrolled. However, it seems that antidepressants are ineffective for these depressions and often trigger a mixed state or frank mania at times. Mood stabilizers and medications effective for bipolar depression may be more appropriate for the depressions in these patients.Usually their sunny temperament itself doesn’t require treatment and may, in fact, foster excellent productivity and creativity during much of their lifespan.

Dr Osser is a Consulting Psychiatrist, US Department of Veterans Affairs, National Telemental Health Center, Bipolar Disorders Telehealth Program, Brockton, MA.

1. Akiskal HS, Mallya G. Criteria for the “soft” bipolar spectrum: treatment implications. Psychopharmacol Bull. 1987;23:68-73.

2. Rihmer Z, Akiskal KK, Rihmer A, Akiskal HS. Current research on affective temperaments. Curr Opin Psychiatry. 2010;23:12-18.

Dark treatment for people with mania

By James Phelps, MD

If light is an antidepressant (true) and antidepressants can make bipolar disorders worse (true), can darkness make bipolar disorders better? Might darkness be anti-manic?

This idea was explored over 2 decades ago, with a stunningly successful case report from the National Institute of Mental Health (NIMH) demonstrating that in at least 1 patient, darkness was indeed a mood stabilizer (1). But the protocol was arduous: 14 hours of enforced darkness every night.

It was so effective, they backed off to 10 hours, from 10 pm to 8 am, which kept the patient well with no medications for over a year. Yet, as clinicians know, patients still resist giving up their electric light, especially their TVs, tablets, and phones.

Hold that thought; and consider a completely separate line of research, which found that all wavelengths of light are not created equal. Blue light is by far the most powerful in setting circadian rhythm.

A new retinal photoreceptor, not a rod or cone, was discovered in 2001; it is sensitive primarily to blue light (2). These receptors connect not to the visual cortex but to the suprachiasmatic nucleus of the hypothalamus, wherein resides the primary biological clock. They are “circadian photoreceptors.”

Now put these 2 lines of research together. At night, when evolutionarily we should have 8 to 14 hours of darkness, one can create “virtual darkness” by blocking just the blue wavelengths of light. This can be done at the source (F.lux for Windows; NightShift for recent Apple products; and lowbluelights.com for no-blue bulbs and nightlights) or by simply donning a pair of amber-colored safety glasses.

The latter are available as fit-over-glasses, # S0360X; or a stylish version for young people with good eyes, # 3S1933X (purchase from Amazon—or, in a fun twist, from your local Airgas welding shop, ~$9). These safety glasses have been shown to preserve melatonin production at night even in a fully lit environment.3 About 50% of patients responded to wearing the amber lenses with reduced sleep latency and improved sleep quality (4).

But now the acid test: if darkness is a mood stabilizer, and if amber lenses produce physiologic darkness, then can the lenses treat acute mania?

This has just been shown quite conclusively(5) (to the extent that a single randomized trial is conclusive; but note this is a replication of another small inpatient study that used real darkness and found similar, though slightly less robust results (6).

In the new study from Norway, patients being admitted with bipolar mania were randomized to wear amber lenses or control clear lenses whenever they were not in real darkness during the 14-hour period from 6 pm to 8 am.

Thus, they replicated the intervention from the NIMH case report, using either real or “virtual darkness” with the amber lenses. The intervention began near admission and continued for 7 days, during which all participants received other treatments, including anti-manic medications, per usual.

Young Mania Rating Scale (YMRS) scores plummeted in the amber lenses group while those of the control group diminished only slightly: starting from a mean YMRS of 25, reductions were 14.1 vs 1.7, respectively.

Unfortunately, the sample size was smaller than originally intended because of growing public awareness of the effects of blue light and blue light–blocking glasses and consequently the patients knew what effect to expect. Thus, this may be the only such study we’ll ever see, and it took 10 years to replicate the first inpatient study6 of dark therapy.

So I hope that this new Norwegian study will not be dismissed as a pilot. The data are in. Time to move dark therapy into regular practice, as has already been suggested in the latest bipolar-specific psychotherapy, “CBT-IB: A Bipolar-Specific, All-Around Psychotherapy.”

But patients are often hesitant to increase their exposure to darkness: it means giving up things they value, especially television and other electronic entertainment. Blue light blockade can be much more acceptable.