Clinical meaning
Mental health exists on a continuum that ranges from optimal psychological well-being to severe mental illness, with most individuals moving along this spectrum throughout their lives in response to biological, psychological, social, and environmental factors. The neurobiological basis of mental health involves the complex interplay of neurotransmitter systems, neural circuits, neuroendocrine pathways, and genetic predispositions. The major neurotransmitters implicated in mental health disorders include serotonin (5-HT), which regulates mood, sleep, appetite, and impulse control; norepinephrine, which modulates alertness, concentration, and the stress response; dopamine, which influences motivation, reward, pleasure, and motor function; gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter that reduces neuronal excitability and anxiety; and glutamate, the primary excitatory neurotransmitter. Depression is associated with decreased serotonin and norepinephrine activity in the prefrontal cortex and limbic system. Anxiety disorders involve dysregulation of the GABA system and hyperactivity of the amygdala, the brain structure responsible for fear processing and emotional memory. Psychotic disorders such as schizophrenia involve excess dopamine activity in the mesolimbic pathway (causing positive symptoms like hallucinations and delusions) and decreased dopamine activity in the mesocortical pathway (causing negative...