"Single Dose of Antidepressant Changes the Brain" - The Trouble with Ignorant Science Writers

"Single Dose of Antidepressant Changes the Brain," that was the headline from Science Codex on Thursday, and their headline resembled a lot of others, as well. Here are some other examples, from Time Magazine, "One Dose of Antidepressant Changes the Brain, Study Finds,"or from The Examiner, "SSRIs change brain structure fast," or from Psych Central, "Single Dose of Antidepressant Changes the Brain."

So, what't the problem with these headlines?

The issue is that the study never claimed that SSRIs change the brain (and especially not brain structure) but, rather, they found (as others have before them) that a single dose of an SSRI can alter functional connectivity in the brain.

For the purpose of clarity (via Wikipedia):

Functional connectivity is the connectivity between brain regions that share functional properties. More specifically, it can be defined as the temporal correlation between spatially remote neurophysiological events, expressed as deviation from statistical independence across these events in distributed neuronal groups and areas.

Functional connectivity is dynamic, which means it can change at the order of seconds in response to stimuli of various types.

What the study actually found is that an SSRI (Lexapro in this study) reduces the level of intrinsic connectivity in most parts of the brain, while it increases connectivity within two brain regions, specifically the cerebellum and thalamus. From Laird, et al (2013):

The term “intrinsic connectivity network” (Seeley et al., 2007), therefore, expands upon the concept of resting state networks to include the set of large-scale functionally connected brain networks that can be captured in either resting state or task-based neuroimaging data.

From Wikipedia:

The cerebellum (Latin for "little brain") is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses;[1] its movement-related functions are the most solidly established. The cerebellum does not initiate movement, but it contributes to coordination, precision, and accurate timing. It receives input from sensory systems of the spinal cord and from other parts of the brain, and integrates these inputs to fine tune motor activity.[2]

And...

The thalamus has multiple functions. It may be thought of as a kind of switchboard of information. It is generally believed to act as a relay between different subcortical areas and the cerebral cortex. In particular, every sensory system (with the exception of the olfactory system) includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area. For the visual system, for example, inputs from the retina are sent to the lateral geniculate nucleus of the thalamus, which in turn projects to the visual cortex in the occipital lobe. The thalamus is believed to both process sensory information as well as relay it—each of the primary sensory relay areas receives strong feedback connections from the cerebral cortex. Similarly the medial geniculate nucleus acts as a key auditory relay between the inferior colliculus of the midbrain and the primary auditory cortex, and the ventral posterior nucleus is a key somatosensory relay, which sends touch and proprioceptive information to the primary somatosensory cortex.

The thalamus also plays an important role in regulating states of sleep and wakefulness.[10] Thalamic nuclei have strong reciprocal connections with the cerebral cortex, forming thalamo-cortico-thalamic circuits that are believed to be involved with consciousness. The thalamus plays a major role in regulating arousal, the level of awareness, and activity. Damage to the thalamus can lead to permanent coma.

The role of the thalamus in the more anterior pallidal and nigral territories in the basal ganglia system disturbances is recognized but still poorly understood. The contribution of the thalamus to vestibular or to tectal functions is almost ignored. The thalamus has been thought of as a "relay" that simply forwards signals to the cerebral cortex. Newer research suggests that thalamic function is more selective.[11] Many different functions are linked to various regions of the thalamus. This is the case for many of the sensory systems (except for the olfactory system), such as the auditory, somatic, visceral, gustatory and visual systems where localized lesions provoke specific sensory deficits. A major role of the thalamus is devoted to "motor" systems. The thalamus is functionally connected to the hippocampus [12] as part of the extended hippocampal system at the thalamic anterior nuclei[13] with respect to spatial memory and spatial sensory datum they are crucial for human episodic memory and rodent event memory.[14][15] There is support for the hypothesis that thalamic regions connection to particular parts of the mesio-temporal lobe provide differentiation of the functioning of recollective and familiarity memory.[9]

The neuronal information processes necessary for motor control were proposed as a network involving the thalamus as a subcortical motor centre.[16] Through investigations of the anatomy of the brains of primates[17] the nature of the interconnected tissues of the cerebellum to the multiple motor cortices suggested that the thalamus fulfills a key function in providing the specific channels from the basal ganglia and cerebellum to the cortical motor areas.[18][19] In an investigation of the saccade and antisaccade[20] motor response in three monkeys, the thalamic regions were found to be involved in the generation of antisaccade eye-movement.[21]

It's unclear how these structures are involved in depression, although the thalamus is connected to the hypothalamus, which is impacted by trauma (since it plays a role in memory) and which may play a role in depression due to its function in memory and emotional processing.

Based on all of this it is clear that the study in question was greatly simplified in the press releases and media coverage.

For a more educated takedown of the press coverage of this study, Neuroskeptic has written a great post.

 

Family problems are now recognized as a contributing factor for mental illness - and there is brain imaging research to support what many therapists have known for decades.

Using brain imaging technology to scan teenagers aged 17-19, the researchers in this study found that those who experienced mild to moderate family difficulties between birth and 11 years of age had a smaller cerebellum, which is an area of the brain associated with skill learning, stress regulation, and sensory-motor control. The researchers suggest that a smaller cerebellum may be a risk indicator of psychiatric disease later in life, as it is consistently found to be smaller in virtually all psychiatric illnesses.

So when you hear that parents divorced for the kids (rather than staying together for the kids), there is evidence that they did the correct thing. Other more specific research has identified parental discord as a risk factor for children developing behavioral and mental health issues. And this is only one of many possible forms of "family problems."

Family problems experienced in childhood and adolescence affect brain development

Date: February 19, 2014
Source: University of East Anglia

Summary:
New research has revealed that exposure to common family problems during childhood and early adolescence affects brain development, which could lead to mental health issues in later life. The study used brain imaging technology to scan teenagers aged 17-19. It found that those who experienced mild to moderate family difficulties between birth and 11 years of age had developed a smaller cerebellum, an area of the brain associated with skill learning, stress regulation and sensory-motor control. The researchers also suggest that a smaller cerebellum may be a risk indicator of psychiatric disease later in life, as it is consistently found to be smaller in virtually all psychiatric illnesses.

Areas in blue are brain regions shown to be smaller as a result of childhood adversities occurring aged 0-11, and regions in orange are shown to be larger as a result of exposure to negative life events aged 14.  Credit: Image courtesy of University of East Anglia

New research has revealed that exposure to common family problems during childhood and early adolescence affects brain development, which could lead to mental health issues in later life.

The study led by Dr Nicholas Walsh, lecturer in developmental psychology at the University of East Anglia (UEA), used brain imaging technology to scan teenagers aged 17-19. It found that those who experienced mild to moderate family difficulties between birth and 11 years of age had developed a smaller cerebellum, an area of the brain associated with skill learning, stress regulation and sensory-motor control. The researchers also suggest that a smaller cerebellum may be a risk indicator of psychiatric disease later in life, as it is consistently found to be smaller in virtually all psychiatric illnesses.

Previous studies have focused on the effects of severe neglect, abuse and maltreatment in childhood on brain development. However the aim of this research was to determine the impact, in currently healthy teenagers, of exposure to more common but relatively chronic forms of 'family-focused' problems. These could include significant arguments or tension between parents, physical or emotional abuse, lack of affection or communication between family members, and events which had a practical impact on daily family life and might have resulted in health, housing or school problems.

Dr Walsh, from UEA's School of Psychology, said: "These findings are important because exposure to adversities in childhood and adolescence is the biggest risk factor for later psychiatric disease. Also, psychiatric illnesses are a huge public health problem and the biggest cause of disability in the world.

"We show that exposure in childhood and early adolescence to even mild to moderate family difficulties, not just severe forms of abuse, neglect and maltreatment, may affect the developing adolescent brain. We also argue that a smaller cerebellum may be an indicator of mental health issues later on. Reducing exposure to adverse social environments during early life may enhance typical brain development and reduce subsequent mental health risks in adult life."

The study, which was conducted with the University of Cambridge and the Medical Research Council Cognition and Brain Sciences Unit, Cambridge, is published in the journal NeuroImage: Clinical.

The 58 teenagers who took part in the brain scanning were drawn from a larger study of 1200 young people, whose parents were asked to recall any negative life events their children had experienced between birth and 11 years of age. The interviews took place when the children were aged 14 and of the 58, 27 were classified as having been exposed to childhood adversities. At ages 14 and 17 the teenagers themselves also reported any negative events and difficulties they, their family or closest friends had experienced during the previous 12 months.

A "significant and unexpected" finding was that the participants who reported stressful experiences when aged 14 were subsequently found to have increased volume in more regions of the brain when they were scanned aged 17-19. Dr Walsh said this could mean that mild stress occurring later in development may 'inoculate' teenagers, enabling them to cope better with exposure to difficulties in later life, and that it is the severity and timing of the experiences that may be important.

"This study helps us understand the mechanisms in the brain by which exposure to problems in early-life leads to later psychiatric issues," said Dr Walsh. "It not only advances our understanding of how the general psychosocial environment affects brain development, but also suggests links between specific regions of the brain and individual psychosocial factors. We know that psychiatric risk factors do not occur in isolation but rather cluster together, and using a new technique we show how the general clustering of adversities affects brain development."

The researchers also found at that those who had experienced family problems were more likely to have had a diagnosed psychiatric illness, have a parent with a mental health disorder and have negative perceptions of their how their family functioned.

Story Source: The above story is based on materials provided by University of East Anglia. Note: Materials may be edited for content and length.

Journal Reference:
Nicholas D. Walsh, Tim Dalgleish, Michael V. Lombardo, Valerie J. Dunn, Anne-Laura Van Harmelen, Maria Ban, Ian M. Goodyer. General and specific effects of early-life psychosocial adversities on adolescent grey matter volume. NeuroImage: Clinical, 2014; 4: 308 DOI: 10.1016/j.nicl.2014.01.001