Sleep and psychopathology

New Scientist has a fascinating article on sleep and mental illness. While it’s long been known that mental illness can disrupt sleep the article discusses the much less explored connection where loss of sleep might trigger symptoms of mental illness in some.

Until recently, however, the assumption that poor sleep was a symptom rather than a cause of mental illness was so strong that nobody questioned it. “It was just so easy to say about a patient, well, he’s depressed or schizophrenic, of course he’s not sleeping well – and never to ask whether there could be a causal relationship the other way,” says Robert Stickgold, a sleep researcher at Harvard University. Even when studies did seem to point in the other direction, the findings were largely overlooked, he says.

Scientifically, sleep and mental illness have been long linked. Theories of bipolar disorder as a disruption to circadian rhythms have been kicking round for years and treatments that reduce disruption to sleep routines are known to have a therapeutic effect.

The NewSci article reviews various studies that suggest sleep problems can increase risk for mental illness, but it doesn’t mention an equally interesting link.

We also know that sleep deprivation can help otherwise untreatable mood disorders. For example, missing a night’s sleep can be used as a treatment in depression.

Link to article ‘Are bad sleeping habits driving us mad?’.

Why smokers blunt their caffeine hit

Image by Flickr user sheeshoo. Click for sourceI was just reading an interesting paper on the interaction between antipsychotic drugs, caffeine and smoking and I found this interesting snippet on how smokers need to take in three to four times more caffeine than non-smokers to get the same effect, owing to the fact that by products of increases enzymes in the liver which break-down caffeine.

Byproducts of tobacco smoking, particularly the polycyclic aromatic hydrocarbons, are metabolic inducers. These byproducts are inducers of the [liver enzyme] cytochrome P450 isoenzyme 1A2 (CYP1A2) and of the less understood UDP-glucuronosyltransferases (UGTs).The metabolic inductive effects are not specific to tobacco smoking; they can also be expected from marijuana smoking.

Because inducers require the synthesis of new enzymes, several weeks are usually needed before the maximum effects of inducers are seen. Inducers’ effects may take a few weeks to disappear as well….

Additional pharmacologic support of the relevance of smoking’s inductive effects comes from caffeine intake studies. Caffeine, a drug that is more than 90 percent dependent on CYP1A2 for its metabolism and that is widely used in the United States, can exemplify smoking’s effects on drug metabolism.

The C/D [concentration-dose ratio] of caffeine appears to be threefold to fourfold as high among nonsmokers compared with smokers. This higher ratio means that smokers need three to four times the caffeine “dosage” as nonsmokers on average to get the same plasma caffeine levels.

It turns out that two antipsychotic drugs, olanzapine and clozapine, are also broken down by the same enzyme, so smoking will reduce the effect of these drugs.

Hence smokers need larger doses to have the same effect, and patients on these drugs who give up smoking might find a sudden increase in side effects if the dose isn’t dropped.

We tend to think of the effect of psychotropic drugs as happening in the brain but drug metabolism happens all over the body with the liver and kidneys being particularly important and having a profound impact on the effect of the compound.

Link to ‘Atypical Antipsychotic Dosing: The Effect of Smoking and Caffeine’.

It was planted on me

I have discovered that there is small but budding group of cognitive scientists who study the psychological impact of indoor plants.

For example, here is a study on the effects of an indoor plant on creativity and mood from the Scandinavian Journal of Psychology.

Effects of an indoor plant on creative task performance and mood.

Shibata S, Suzuki N.

Scandinavian Journal of Psychology. 2004 Nov;45(5):373-81.

In this study, we investigated the effect of an indoor plant on task performance and on mood. Three room arrangements were used as independent variables: a room with (1) a plant, or (2) a magazine rack with magazines placed in front of the participants, or (3) a room with neither of these objects.

Undergraduate students (M= 35, F= 55) performed a task of associating up to 30 words with each of 20 specified words in a room with one of the three room arrangements. Task performance scores showed that female participants performed better in view of the plant in comparison to the magazine rack (p < 0.05).

Moreover, mood was better with the plant or the magazine rack in the room compared to the no object condition (p < 0.05). However, the difference in task performance was highly influenced by the evaluation about the plant or the magazine rack. It is suggested that the compatibility between task demand and the environment is an important factor in facilitating task performances.

Somehow, I feel my world view has not actually changed after reading that study.

But wait, there are also published research studies on:

Effects of the foliage plant on task performance and mood.

Effects of indoor plants on task performance and mood: a comparison between natural and imitated plants.

Influence of limitedly visible leafy indoor plants on the psychology, behavior, and health of students at a junior high school in Taiwan.

The association between indoor plants, stress, productivity and sick leave in office workers.

And someone even did their PhD on “Randomized clinical trials evaluating therapeutic influences of ornamental indoor plants in hospital rooms on health outcomes of patients recovering from surgery”.

Link to PubMed entry for Scandinavian Journal of Psychology study.

A cognitive science of spiritual healing?

Time magazine has an interesting article on the neuroscience of spiritual experience and why religious belief has been linked to better health.

It’s not the most gripping article in the world and starts with some annoying experience = brain area phrenology but it does gives a good overview of some of the main research areas.

Probably the most interesting aspect is where it tackles the link between religious belief and health in light of other belief based health benefits such as the placebo effect or beliefs about illness itself.

The section on the effects of prayer also has this fascinating snippet about early experimental psychologist Francis Galton:

As long ago as 1872, Francis Galton, the man behind eugenics and fingerprinting, reckoned that monarchs should live longer than the rest of us, since millions of people pray for the health of their King or Queen every day. His research showed just the opposite — no surprise, perhaps, given the rich diet and extensive leisure that royal families enjoy.

Studies on the curative properties of prayer have a long and interesting history, with one of the most striking moments also linked to a psychologist and an (in)famous study – discussed in a 2002 Wired article.

Link to Time article ‘The Biology of Belief’.

The scientific legacy of HM’s missing memories

The latest edition of Neuron has a fantastic tribute to the recently departed amnesic Patient HM, “probably the best known single patient in the history of neuroscience”, covering the scientific work he participated in and what it has told us about the structure of memory.

The piece is by respected memory researcher Larry Squire and he tackles HM’s personal history while also reviewing his contributions to science through numerous landmark studies.

It can be said that the early descriptions of H.M. inaugurated the modern era of memory research. Before H.M., due particularly to the influence of Karl Lashley, memory functions were thought to be widely distributed in the cortex and to be integrated with intellectual and perceptual functions.

The findings from H.M. established the fundamental principle that memory is a distinct cerebral function, separable from other perceptual and cognitive abilities, and identified the medial aspect of the temporal lobe as important for memory.

The implication was that the brain has to some extent separated its perceptual and intellectual functions from its capacity to lay down in memory the records that ordinarily result from engaging in perceptual and intellectual work.

The article is fascinating not least because it dispels a few common myths about HM – such as the original study showed the hippocampus was necessary for memory when HM also had the amygdala and parahippocampal gyrus removed and so it wasn’t possible to say which were most important.

It also notes that the original studies over-stated how much brain was removed owing to the basic knowledge of neuroanatomy that existed at the time.

Link to ‘The Legacy of Patient H.M. for Neuroscience’.
Link to PubMed entry for same.

You change your diagnosis like a girl changes clothes

A recently published study in the Journal of Affective Disorders found that clinicians are less likely to suggest a diagnosis of bipolar disorder if the patient is described as having recently fallen in love, even if they are reported to have all the necessary symptoms.

I notice that Katy Perry addressed exactly this issue in her global pop hit Hot N’ Cold.

You’re hot then you’re cold
You’re yes then you’re no
You’re in and you’re out
You’re up and you’re down

Someone call the doctor
Got a case of a love bipolar

Perry clearly demonstrates that she’s not subject to this particular diagnostic bias as she is able to recognise that the patient has fallen in love, but also qualifies for a diagnosis of bipolar based solely on presenting features.

Link to PubMed entry for study.
Link to video of Katy Perry’s Hot N’ Cold.