Adaptive capacity and the ability to sustain long-term changes as neural activity patterns are considered as the most critical and intriguing properties of the brain. This concept, called neuroplasticity, refers to the ability of the brain to adapt and change over time. Sometimes, re-organization or re-adaptation mediates crucial physiological events such as learning and memory by long-term potentiation, but sometimes, especially under heavily stressful internal or external conditions, contra-adaptation may underlie several neuropsychiatric diseases. Neuroplasticity is a continuous process that reacts to inter- and intraneuronal activity and neural injury, in parallel with apoptosis and structural or functional changes in neurites and synapses. Elements of signal transduction cascades (SDCs) between and within neurons include neurotransmitters, receptors, G proteins, secondary messengers, protein kinases, and transcription factors. If any of these elements fail, pathological conditions (contra-adaptation) occur in the brain. Each step of neurotransmission is influenced by changes in genes and DNA via SDCs. In fact, neuroplasticity is a result of adaptive genomic changes in SDC, and it is a product of gene plasticity or genoplasticity. At present, we do not yet have any radical solutions for the treatment of important neuropsychiatric diseases. Some external and internal factors may change the task definition of neurons by causing genomic changes and the resulting mutant or “terrorist” neurons may cause severe brain disorders.