Sluggish schizophrenia or slow progressive schizophrenia (Russian: вялотеку́щая шизофрени́я, romanized: vyalotekushchaya shizofreniya) was a diagnostic category used in the Soviet Union to describe what was claimed to be a form of schizophrenia characterized by a slowly progressive course; it was diagnosed even in patients who showed no symptoms of schizophrenia or other psychotic disorders, on the assumption that these symptoms would appear later. It was developed in the 1960s by Soviet psychiatrist Andrei Snezhnevsky and his colleagues, and was used exclusively in the USSR and several Eastern Bloc countries, until the fall of Communism starting in 1989. The diagnosis has long been discredited because of its scientific inadequacy and its use as a means of confining dissenters. It has never been used or recognized outside of the Eastern Bloc, or by international organizations such as the World Health Organization. It is considered a prime example of the political abuse of psychiatry in the Soviet Union.

Sluggish schizophrenia was the most infamous of diagnoses used by Soviet psychiatrists, due to its usage against political dissidents. After being discharged from a hospital, persons diagnosed with sluggish schizophrenia were deprived of their civic rights, credibility and employability. The usage of this diagnosis has been internationally condemned.

In the Russian version of the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), which has long been used throughout present-day Russia, sluggish schizophrenia is no longer listed as a form of schizophrenia, but it is still included as a schizotypal disorder in section F21 of chapter V.

According to Sergei Jargin, the same Russian term "vyalotekushchaya" for sluggish schizophrenia continues to be used and is now translated in English summaries of articles not as "sluggish" but as "slow progressive".

The term "sluggish schizophrenia" was introduced in the Soviet Union in the 1930s by Dr. Grunia Sukhareva. Sukhareva first used the term in a 1933 article in which she described a type of schizophrenia that developed slowly in children beginning before puberty. Sukhareva's term became a standard part of Soviet textbooks on schizophrenia in the 1940s. In the 1960s, Professor Andrei Snezhnevsky, the most prominent theorist of Soviet psychiatry and director of the Institute of Psychiatry of the USSR Academy of Medical Sciences, developed a novel classification of mental disorders postulating an original set of diagnostic criteria. Snezhnevsky and his colleagues who developed the concept were supported by Soviet psychiatrists Fedor Kondratev, Sergei Semyonov, and Yakov Frumkin. All were members of the "Moscow school" of psychiatry.

A majority of experts believe that the concept was developed under instructions from the Soviet secret service KGB and the Communist Party.

Psychiatric diagnoses such as sluggish schizophrenia were used in the USSR for political purposes; the diagnosis of sluggish schizophrenia was most frequently used for Soviet dissidents. Sluggish schizophrenia as a diagnostic category was created to facilitate the stifling of dissidents and was a root of self-deception among psychiatrists to placate their consciences when the doctors acted as a tool of oppression in the name of a political system. American psychiatrist Peter Breggin points out that the term "sluggish schizophrenia" was created to justify involuntary treatment of political dissidents with drugs normally used for psychiatric patients.

Critics implied that Snezhnevsky designed the Soviet model of schizophrenia (and this diagnosis) to make political dissent a mental illness.