Neuropsychology

1. Neuropsychology studies how the structure and activity of the brain link to behaviour and mental processes.
2. It gives psychologists a way to investigate schizophrenia and clinical depression from a biological angle.
3. The two methods are neuropsychological tests and brain imaging techniques.

The development of neuropsychology

1. The earliest evidence came from people with brain injuries, whose lost abilities showed what the damaged area had been doing.
2. Post-mortem examination came next, so a brain could be compared with the behaviour recorded during that person's life.
3. Both approaches needed damage or death, so nothing could be learned about a healthy living brain at work.
4. Standardised tests then made it possible to measure one thinking skill in a living person and compare their score with typical scores.
5. Brain imaging from the 1970s onwards, beginning with CT, added pictures of the living brain, and functional scanning later showed which parts were working during a task.
6. Schizophrenia and clinical depression can therefore now be studied in living people, during ordinary thinking, without waiting for injury or death.

Neuropsychological tests

1. A neuropsychological test is a standardised task that measures a specific mental ability such as memory, attention or problem-solving.
2. Standardising it means every person does the same task in the same way, so their scores can be compared fairly.
3. Comparing a person's score with the typical score for their age shows up difficulties linked to a condition.
4. The Wisconsin Card Sort Test measures the planning and strategy-switching that the frontal lobes handle.
5. People with schizophrenia often score poorly on it, which points to frontal lobe dysfunction.
6. In clinical depression, tests often show slowed thinking, poorer concentration and weaker memory, which matches the ICD characteristics.
7. Because the tasks are standardised, the results are objective and quantitative.

Brain imaging techniques

1. Structural scans such as CT and MRI produce detailed images of the brain, showing its size, its shape and any damage.
2. Functional scans such as fMRI, PET and SPECT show which areas are active, by tracking blood flow while a person carries out a task.
3. Blood flow works as the measure because a working area of brain needs more oxygen, so more blood is sent to it.
4. In schizophrenia, scans may show enlarged ventricles, a smaller hippocampus or reduced activity in the frontal lobes.
5. Over-activity in the temporal lobes has also been reported, and it is associated with hallucinations and disordered thinking.
6. In clinical depression, imaging may show differences in activity in the areas involved in mood, and reduced hippocampal volume where depression has lasted for years.
7. Daniel et al. (1991) paired a SPECT scan with the Wisconsin Card Sort Test, so a scan and a test were used together in one study.
   1. A scan is a snapshot, so its findings describe patterns across a group.

Strengths of these techniques

1. Strength, objectivity: tests and scans give measurable, quantitative data.
2. Strength, safety: imaging is non-invasive, so a living brain can be studied without surgery.
3. Strength, practical use: a scan can rule out a physical cause such as a tumour, and repeated tests can track whether a treatment is helping.

Weaknesses of these techniques

1. Weakness, correlation: a difference in the brain may be a result of the condition, or of long-term medication, rather than its cause.
2. Weakness, overlap: many of these findings turn up in people without the condition too, so a scan cannot diagnose depression or schizophrenia by itself.
3. Weakness, a narrow focus: looking only at biology misses social and psychological factors, so these techniques work best alongside other evidence.

Turning this into marks

1. When two techniques are asked for, make them genuinely separate: a neuropsychological test measures thinking, and a scan shows the brain.
2. Name the technique, such as the Wisconsin Card Sort Test or an fMRI scan, because a general reference to brain research does not secure the knowledge mark.
3. The mark most often lost is treating a scan as a way of diagnosing schizophrenia or depression.