The cognitive explanation of depression can be criticised for being over-simplified. For example, the cognitive explanation states that if an individual thinks in a negative way/has negative automatic thoughts they are likely to develop disorders such as depression. This is a criticism because this theory of depression ignores the fact that the biological research has indicated that depression can be down to low levels of the neurotransmitter, serotonin, and therefore, the cognitive approach can be seen to be too simplistic