The basis of psychopathology is the doctrine of symptoms, syndromes and mental disorders as a complex set and a natural combination of syndromes in various types of their evolution (specific pathokinesis).
Symptoms of the disease (from the Greek Συμπτωμα which means "indicator, case, coincidence") are a reflection of the pathological state of various functional systems ensuring integration of mental activity. When a symptom is recognised and assessed, its external manifestation, characteristic, severity, and the possibility of objectification are important too, since, with different symptoms, different behavioural patients' specialities being fixed objectively are noted.
At the same time, explanation, interpretation of various symptoms as a reflection of disorder of a certain mental state or process (perception, thinking, emotions) is relative to a certain extent, e.g. in the case of delusion, it questions not only about thinking process disorder but also, in a number of cases, about affective disturbance, memory deception, disorder of self-awareness, etc. In cases, when subjective and objective components of a symptom are the same, it is possible to describe symptoms of the disease quite exactly; this, no doubt, helps to clarify the diagnosis and gives a possibility to do the purposeful efficient treatment.
Symptoms themselves rarely exhaust the clinical picture of a mental disorder, e.g., such symptoms as anxiety and fear develop in people of the alarmingly suspicious type (S.A. Sukhanov, 1912) on different stages of their life, when such people are exposed to various stress factors or in fearful people (Theophrastus, 4th century B.C., Cicero, 1st century B.C.) much more often, anxiety and fear are combined with other symptoms, such as affective depression, delusional tension, etc. In such cases, this means the formation of symptom complexes (the term has been introduced by W. Griesinger, 1845, 1881) or syndromes (R. Krafft-Ebing, 1897).