Biological Model of Abnormal Psychology

The link between a particular cluster of symptoms and an underlying impairment in physiologic function is emphasized in biological models of psychopathology. In the biological model, genetic factors, brain abnormalities, neurotransmitter dysfunctions, and other biological factors are considered the cause of psychiatric abnormalities.

What does Biological Model of Abnormal Psychology Refer?

The biological model of abnormal psychology presents a detailed understanding of biological processes as a basis of abnormal behavior. In the biological model, the thoughts and feelings of an individual are explained through the biochemical and bioelectrical processes within the body and the brain.

Importance of Biological Variables

Biological variables or factors play a very important role in determining abnormal behavior, which can be viewed from two angles. On the one hand, they can be seen as the main etiological reasons, much like when a disorder's etiology has a significant hereditary component. On the other hand, they can also be seen as an organismic variable (i.e., individual differences) that interacts with the environment to influence the symptom of choice.

Biological Theorists Explanation of the Model

  • Brain Anatomy and Abnormal Behavior
  • Brain Chemistry and Abnormal Behavior

Let us understand the biological model through brain anatomy and brain chemistry.

Brain Anatomy and Abnormal Behavior

Brain Anatomy plays an important role in diagnosing abnormal behavior. The brain comprises billions of support cells called "glia" and about 100 billion nerve cells called neurons. The brain is divided into various regions by vast clusters of neurons. For instance, the cerebrum, which comprises the cortex, corpus callosum, basal ganglia, hippocampus, and amygdala, is a collection of areas towards the top of the brain. The neurons in each of these areas of the brain regulate crucial processes. The cortex is the brain's outer layer; the corpus callosum connects the two cerebral hemispheres; the basal ganglia is essential for planning and moving; the hippocampus aids in emotion and memory regulation, and the amygdala is necessary for emotional memory.

Clinical experts have found links between several psychological diseases and abnormalities in particular brain parts. One such condition is Huntington's disease, characterized by violent emotional outbursts, memory loss, suicidal thoughts, and uncontrollable bodily motions. It is related to the loss of cells in the basal ganglia and cortex.

Brain Chemistry and Abnormal Behavior

Biological experts have shown that issues with message transmission from one neuron to another can be connected to psychiatric diseases, which lead to abnormal behavior. It can be understood that electrical impulses that move from one neuron to one or more others carry information throughout the entire brain. A neuron's dendrites, antenna-like projections found at one end of the cell, are the first to pick up an impulse. It then proceeds along the axon, a protruding fiber from the neuron's body. Finally, it is sent to the dendrites of other neurons via the nerve ending at the end of the axon.

The neurons do not touch each other. One neuron is separated from the next by a very small gap known as a synapse, and the message must traverse this gap somehow. A neuron's terminal is activated by an electrical impulse to release a substance known as a neurotransmitter, which travels across the synaptic space to receptors on the dendrites of the surrounding neurons. Some neurotransmitters send a signal to receiving neurons to "fire" or to start their electrical impulse after attaching to the receptors on the receiving neuron. Other neurotransmitters provide sensory neurons an inhibitory message, instructing them to cease all firing.

As you can see, neurotransmitters are essential for the brain's ability to transfer information. Studies indicate that abnormal activity by certain neurotransmitters can lead to specific mental disorders and abnormalities in behavior. For example, Depression has been linked to low activity of the neurotransmitters serotonin and norepinephrine.

Biological Causes of Abnormality

It includes -

  • Genetics − Abnormal behavior can also be caused due to genetic inheritance. According to studies, schizophrenia, mood disorders, and other mental disorders may also be influenced by inherited traits. It indicates that several genes frequently work together to form healthy and unhealthy human behaviors.

  • Viral Infections − According to studies, schizophrenia is an illness that is caused due to exposure to specific viruses as a child or before birth. This may contribute to developing delusions, hallucinations, and other deviant behaviors. It was seen that others of many people with this disorder contracted influenza or certain viruses throughout their pregnancy.

  • Evolution − Theorists contend that many genes responsible for abnormal functioning resulted from common evolutionary principles. Evolutionary theorists contend that human responses and the genes underlying them have endured over time because they have aided people in thriving and adapting.

Treatments under Biological Model

Once the physical sources of abnormal behavior are identified, a biological course of treatment is chosen. Treatments may includ.

  • Drug Therapy − Psychotropic drugs are used for treatment and are widely used in modern times. One of the examples of such drugs is anti-depressants which are used for people diagnosed with Depression.

  • Electro definitive therapy − In this therapy, two electrodes are joined to a patient's forehead, and an electrical flow of 65 to 140 volts is passed momentarily through the mind. The ongoing process causes a cerebrum seizure that lasts a couple of moments. After seven to nine ECT meetings, separated a few days separated, numerous patients feel significantly less discouragedp

  • Psychosurgery − In psychosurgery, there is a technique known as a lobotomy where a specialist cuts the associations between the frontal lobe and the brain's lower regions. The present psychosurgery systems are significantly more accurate than the lobotomies of the past.


The biological model has proven valuable in adding more information to abnormal psychology. Much research has been done and is continuing to be done in this aspect. However, it also holds some drawbacks in that all abnormal behavior cannot be attributed to the biological factors of the individual. Therefore, the model has pros and cons and is of great importance.