Early views

Current psychiatric classifications

Influenced by findings of the World Health Organization (WHO) collaborative study on acute psychoses (Reference Cooper, Jablensky, Sartorius, Stefanis, Rabavilas and SoldatosCooper 1990), the category of ATPDs (Table 1) appeared in ICD-10 (WHO 1992) within the F2 group ‘schizophrenia, schizotypal and delusional disorders’. The ICD-10 stated that: ‘The limited data and clinical traditions […] do not give rise to concepts that can be clearly defined and separated from each other […]. The nomenclature of these acute disorders is as uncertain as their nosological status’ (WHO 1992: pp. 99–100). ATPDs were characterised by: (a) acute onset (within 2 weeks); (b) early remission (complete recovery is expected within 1–3 months); (c) polymorphic, schizophrenic or predominantly delusional syndromes; and (d) association with ‘acute stress’, regarded as events stressful to most people, such as bereavement, unexpected loss of a partner, job or marriage, or the psychological trauma of combat, terrorism or torture, occurring less than 2 weeks before the onset of psychotic symptoms.

TABLE 1 Main differences between ICD-10 ‘acute and transient psychotic disorders’ and DSM-5 ‘brief psychotic disorder’

The ATPD category comprises six subtypes: ‘acute polymorphic psychotic disorder’ (F23.0) refers to bouffée délirante and Kleist's and Leonhard's cycloid psychosis, featuring varied delusions, hallucinations, perceptual changes, perplexity and emotional turmoil (i.e. intense feelings of happiness or ecstasy, or overwhelming anxiety or marked irritability) that shift daily or even more frequently, and can include ‘schizophrenic symptoms’ (F23.1); ‘acute schizophrenia-like psychotic disorder’ (F23.2) replaced the ICD-9 category ‘acute schizophrenic episode’; ‘acute predominantly delusional psychotic disorder’ (F23.3) involves relatively stable delusions, usually of persecution or reference, and auditory hallucinations; ‘other’ and ‘unspecified’ ATPDs (F23.8–9) are residual classes.

DSM-5 (American Psychiatric Association 2013) listed the category of brief psychotic disorder (Table 1), which features florid psychotic symptoms such as delusions, hallucinations, disorganised speech, and grossly disorganised or catatonic behaviour, lasting less than 1 month. It may follow ‘marked stressors’ or have its onset in the post-partum period. The diagnostic criteria for schizophreniform disorder are unchanged and symptom duration is intermediate between brief psychotic disorder and schizophrenia.

Differential diagnosis

The diagnostic criteria for both ATPD and brief psychotic disorder exclude substance-induced psychosis, organic psychosis due to medical conditions, and affective disorders. There may be states of perplexity and inattention, but not so marked or persistent as to suggest delirium, dementia or substance-induced psychosis; in these cases a differential diagnosis is often difficult. To rule out organic causation and substance misuse, a comprehensive clinical assessment, comprising laboratory testing and neuroimaging, is recommended.

The ATPD subtypes (Fig. 1) with schizophrenic symptoms are set apart from schizophrenia by temporal criteria of less than 1 month's duration, as the ICD-10 diagnosis of schizophrenia requires duration longer than 1 month; the subtypes characterised by polymorphic and predominantly delusional features last less than 3 months. If delusions last longer, the diagnosis will change to ‘persistent delusional disorder’ (F22); if only hallucinations persist for more than 3 months, the diagnosis will be ‘other non-organic psychotic disorders’ (F28).

FIG 1 Differential diagnosis of acute and transient psychoses adapted from ICD-10 (World Health Organization 1992).

Differential diagnosis may also involve transient psychotic symptoms in post-traumatic stress disorder, borderline personality disorder, anorexia nervosa and panic attacks.

Concordance between ICD and DSM

Brief psychotic disorder is an uncommon condition, accounting for just 2–7% of presentations of first-episode psychosis (Reference Korver-Nieberg, Quee and BossKorver-Nieberg 2011; Reference Nugent, Paksarian and MojtabaiNugent 2011; Reference Kingston, Scully and BrowneKingston 2013). Brief psychotic disorder is often a provisional diagnosis (owing to high rates of transition to schizophrenia, schizoaffective disorders or affective disorders) (Reference Nugent, Paksarian and MojtabaiNugent 2011; Reference Kingston, Scully and BrowneKingston 2013), but for patients who do not develop longer-term illness, symptoms seem to be less severe than in schizophrenia and outcome for each episode is favourable (Reference Korver-Nieberg, Quee and BossKorver-Nieberg 2011).

Comparative studies have reported that ATPD extend beyond the category of brief psychotic disorder (Reference Jørgensen, Bennedsen and ChristensenJørgensen 1997; Reference van der Heijden, Tuinier and Kahnvan der Heijden 2004). Reference Marneros and PillmannMarneros & Pillmann (2004) found a closer overlap between the two categories, as nearly two-thirds of their series of patients with ATPDs met the criteria for brief psychotic disorder.

Epidemiology

The incidence of ATPDs ranges from 3.9 to 9.8 cases per 100 000 population, and the rates for the 2-year and 3-year stable ATPD diagnosis are 6.7 and 1.4 respectively (Reference Singh, Burns and AminSingh 2004; Reference Castagnini and FoldagerCastagnini 2013a). Incidence in males peaks early in their mid-20s, whereas the highest rates for women occur 10 years later and are significantly greater than those for men over 45 years old (Reference Castagnini and FoldagerCastagnini 2013a). This pattern is likely to reflect not only the putative effect of female sex hormones on the brain, but also diversities across the ATPD subtypes, as polymorphic psychotic disorder is more common in women; cases with acute schizophrenic features predominate in younger men; and acute predominantly delusional disorder has a later age at onset. Reports on the prevalence of ATPDs are also varied, with greater rates in low- and middle-income countries (Reference Esan and FawoleEsan 2014).

ATPDs have high mortality rates from both natural and unnatural causes (Reference Castagnini, Foldager and BertelsenCastagnini 2013b). The mortality risk is almost twice as high in men, and similar to that for schizophrenia, while there is a small but significant increase in overall and natural-cause mortality compared with bipolar disorder. Suicide is the major cause of premature death and accounts for a quarter of ATPD mortality. Moreover, late-onset ATPDs (over 60 years of age) are associated with a high risk not only of mortality, but also of dementia (Reference Kørner, Lopez and AndersenKørner 2009).

Vulnerability factors

ATPDs are associated with neither specific personality disorders nor premorbid dysfunctions (Reference Jørgensen, Bennedsen and ChristensenJørgensen 1997; Reference Marneros and PillmannMarneros 2004; Reference Singh, Burns and AminSingh 2004). In addition, first-degree relatives of patients with ATPDs have higher rates of ATPDs than family members of patients with schizophrenia; yet the risk of schizophrenia is significantly increased in the family of those with schizophrenia (Reference Das, Malhotra and BasuDas 1999).

Further evidence from a large-scale family study (Reference Castagnini, Laursen and MortensenCastagnini 2013c) reveals that the risk of ATPDs was increased in patients with ATPDs who had first-degree relatives not only with ATPDs, but also with bipolar disorder, and particularly with schizophrenia. Only limited support was provided in terms of family predisposition for the different ATPD subtypes. By contrast, the risk of schizophrenia or bipolar disorder was markedly higher in patients with schizophrenia or bipolar disorder who had family members with the same condition. Similar findings were reported by Reference Kanazawa, Ikeda and GlattKanazawa et al (2013), who conducted a genome-wide association study of 47 individuals with ‘atypical psychosis’, a close variant of ATPDs described in Japan (Reference HatotaniHatotani 1996), and observed that the putative genes overlapped with those for schizophrenia.

Diagnostic stability, course and outcome

A literature review (Reference Castagnini and BerriosCastagnini 2011) reported that acute onset, short duration, absence of premorbid dysfunction and female gender were often associated with diagnostic stability and/or favourable outcome in ATPDs. It was also found that individuals with ATPDs fared better than those with schizophrenia, but no sharp distinction between the two categories can be drawn because about half of patients developed longer-lasting psychotic or affective disorders. In low- and middle-income countries, ATPDs seem to have lower rates of recurrence and higher diagnostic stability. Most studies, however, were small and used retrospective data, probably underpowered to produce meaningful findings. Differences in method, study design and distribution of ATPD subtypes also make comparisons difficult.

More recent studies have collected larger samples and mapped the course and outcome of ATPDs in greater detail. For example, Reference Björkenstam, Björkenstam and HjernBjörkenstam et al (2013) identified 1840 patients diagnosed with a first episode of atypical psychosis in the Swedish Psychiatric Register and found that a third of those affected with ATPDs had not been readmitted within 5 years. The risk of conversion to schizophrenia or schizoaffective disorder was twice as high for patients with ATPDs who had first-degree relatives with schizophrenia or bipolar disorder. Such findings compare favourably with a follow-up study by Reference Aadamsoo, Saluveer and KüünarpuuAadamsoo et al (2011) showing that about half of their patients retained the initial diagnosis of ATPDs, and many had enjoyed stable remission 2 years later. Younger age at onset and longer hospital admission were factors associated with transition to schizophrenia or schizoaffective disorder. Similar findings were reported by Reference Rusaka and RancānsRusaka & Rancāns (2014) in 294 first admissions with ATPDs followed up for 6 years. They observed that abrupt onset, polymorphic psychotic symptoms and anxiety were more common in those who did not develop another diagnosis. On this point, the McLean–Harvard International First-Episode Project (Reference Salvatore, Baldessarini and TohenSalvatore 2011) reported that patients with polymorphic psychotic disorders were less likely than those presenting with acute schizophrenic features to develop schizophrenia or affective psychoses. In keeping with findings of the Münich first-admission psychosis study (Reference Möller, Jäger and RiedelMöller 2011), ATPDs have a better long-term outcome than schizophrenia and delusional disorder.

Further evidence (Reference Castagnini, Foldager and BertelsenCastagnini 2013d, Reference Castagnini and Foldager2014) suggests that nearly half of 5429 patients first listed in the Danish Psychiatric Register with ATPDs did not change diagnosis over a mean 7.3 years, while in the other half there was a broad pattern of shifts in the first 24 months following the initial episode, mainly to either schizophrenia and related disorders (31%) or affective disorders (13%). Although polymorphic psychotic disorder fared better in terms of lower rates of relapse and higher diagnostic stability than the ATPD subtypes with acute schizophrenic or predominantly delusional symptoms, its predictive validity was relatively low.

Lastly, Reference Queirazza, Semple and LawrieQueirazza et al (2014) selected 2923 first admissions with ATPDs in Scotland and estimated that diagnosis remained unchanged in 54% of cases on average after 4 years. Schizophrenia was the most common shift and occurred on average 1.7 years later. Duration of first admission over 2 weeks, age under 30 years and male gender predicted increased risk and earlier transition to schizophrenia.

Treatment

Although patients with ATPDs are usually prescribed antipsychotic medications for acute symptoms and prevention of recurrences, very few clinical trials have addressed the efficacy and safety of treatment (Reference Nugent, Paksarian and MojtabaiNugent 2011). The guidelines for first-episode psychosis promote the use of antipsychotics for 1 to 2 years after remission of psychotic symptoms (International Early Psychosis Association Writing Group 2005), and the National Institute for Health and Care Excellence (NICE; 2014) clinical guidelines for psychosis and schizophrenia do not cover transient psychotic disorder. The NICE guidelines recommend psychosocial therapy (i.e. cognitive–behavioural therapy and/or family intervention) for 1 month or less for patients with psychosis who prefer it, then the offer of alternative treatments, including antipsychotics.

In the absence of specific guidance, protracted treatment with antipsychotics needs to be considered cautiously, as several side-effects have been described with both typical and atypical antipsychotics; the latter are also more likely to induce potential adverse effects, such as weight gain and metabolic syndrome, which are associated with increased risk of cardiovascular disease, diabetes and premature mortality (Reference Saha, Chant and McGrathSaha 2007). It would appear that the highest natural-cause mortality not only for schizophrenia – where the long-term side-effects of antipsychotics are known to be complicated by behavioural factors such as cigarette smoking, substance misuse, poor diet and a sedentary life-style – but also for ATPDs resulted from cardiovascular and endocrine/metabolic comorbidities (Reference Castagnini, Foldager and BertelsenCastagnini 2013b).

More to the point, a treatment trial involving patients with first-episode psychosis reported that those who discontinued or reduced medication 6 months after symptom remission fared better over the long term than those who remained on maintenance treatment for a further 18 months (Reference Wunderink, Nieboer and WiersmaWunderink 2013).

Many individuals with acute psychosis need hospital admission owing to disorganised behaviour, impaired insight, and aggressive and suicidal acts; they require careful risk assessment and a management plan.

Shortcomings of the ATPD category

The relationship of ATPDs and mood disorders

Although the ATPD criteria require exclusion of both depressive and manic episodes, emotional changes and affective symptoms may be frequent and transitions tend to occur not only to schizophrenia, but also to affective disorders over the short and longer term (Reference Jørgensen, Bennedsen and ChristensenJørgensen 1997; Reference Marneros and PillmannMarneros 2004; Reference Aadamsoo, Saluveer and KüünarpuuAadamsoo 2011; Reference Castagnini, Foldager and BertelsenCastagnini 2013d, Reference Castagnini and Foldager2014; Reference Queirazza, Semple and LawrieQueirazza 2014; Reference Rusaka and RancānsRusaka 2014). Patients presenting with polymorphic psychotic symptoms are also more likely to develop bipolar disorder than those with schizophrenic or predominantly delusional features, indicating a closer kinship to mood disorders (Reference Marneros and PillmannMarneros 2004; Reference Aadamsoo, Saluveer and KüünarpuuAadamsoo 2011; Reference Salvatore, Baldessarini and TohenSalvatore 2011; Reference Castagnini, Foldager and BertelsenCastagnini 2013d, Reference Castagnini and Foldager2014). Genetic epidemiological studies have challenged a sharp demarcation between ATPDs and schizophrenia, while their relationship to affective disorders deserves clarification (Reference Castagnini, Laursen and MortensenCastagnini 2013c, Reference Castagnini, Munk-Jørgensen and Bertelsen2016).

Clinical implications

ATPDs have been excluded from major epidemiological surveys of first-episode psychosis, and hence the number of people likely to experience acute, florid onset of psychotic symptoms and early remission remains uncertain. The available evidence suggests that ATPDs are rare mental disorders and more often affect women in early to middle adulthood. It is not easy to identify cases in practice, as ATPDs’ distinctive features, such as delusions, hallucinations and emotional turmoil, can change in both type and intensity daily or even faster, and some episodes culminate in impulsive or suicidal acts.

Apart from changes in auditory P300 amplitude, brain scan and cerebral blood flow associated with cycloid psychosis (Reference Beckmann, Franzek, Henn, Sartorius and HelmchenBeckmann 2001), neither structural nor functional brain alterations have been observed in ATPDs. Yet there seems to be greater evidence of psychosocial factors, especially in low- and middle-income countries and migrant populations.

Further evidence indicates that ATPDs have little prognostic validity, as around half of patients developed either schizophrenia and related disorders or, to a lesser extent, affective disorders. While schizophrenic symptoms, young age at onset and male gender are more likely to be associated with subsequent transition to schizophrenia and/or schizoaffective disorders, the effect of acute onset, early remission and shifting polymorphic features on outcome of ATPDs has yet to be established.

Conditions such as the ‘non-affective acute remitting psychoses’ (Reference Susser and WanderlingSusser 1994) have an uneven geographical distribution, with a higher frequency in low- and middle-income countries, particularly in women, and are often associated with stress, fever or systemic infections and fewer negative symptoms than schizophrenia, but seldom fulfil the criteria for ATPDs (Reference Mojtabai, Varma and SusserMojtabai 2000; Reference Nugent, Paksarian and MojtabaiNugent 2011). Transcultural studies suggest a parallel with the socioclinical conditions that characterised the early stages of industrialisation in 19th-century Europe, when bouffée délirante and reactive psychosis were described (Reference GuinnessGuinness 1992).

Nosological implications

Recently published papers have put the study of ATPDs on a new empirical footing and challenged the classification of ATPDs into different subtypes. The proposed revision for ICD-11 (Reference Gaebel, Zielasek and ClevelandGaebel 2012) would introduce a major change by restricting the ATPD category to acute polymorphic psychotic disorder defined by criteria similar to those currently used and a duration shorter than 3 months. The remaining subtypes with schizophrenic and predominantly delusional symptoms would be redistributed into other categories of the newly renamed F2 section ‘schizophrenia spectrum and other primary psychotic disorders’ (Fig. 2). Such changes are expected to bring the ATPDs category closer to the ‘non-affective acute remitting psychoses’, which are reported to have typically 2–4 months’ duration (Reference Mojtabai, Varma and SusserMojtabai 2000). Also under discussion is the proposal to add ‘qualifiers’ for symptoms, course, cognition and functional impairment in order to identify further distinctive features and provide useful information about patients. This reveals more about the technicalities of psychiatric diagnostics than about the disease itself, and it seems questionable whether polymorphic psychotic disorder may constitute a reliable diagnosis because of the lack of clearly defining features.

FIG 2 Proposed changes to ICD-10 F23 category ‘acute and transient psychotic disorders’ and the newly renamed section ‘schizophrenia spectrum and other primary psychotic disorders’ for ICD-11 (adapted from Reference Gaebel, Zielasek and ClevelandGaebel 2012).

An alternative option, by analogy with the DSM-5 category of brief psychotic disorder, would be to select the clinical features that lend themselves to easier assessment, such as acute onset, florid psychotic symptoms and short duration. Close overlap between the two diagnostic categories might have benefits for practice, research and the wider understanding of these conditions.

MCQs

Select the single best option for each question stem

1. 1 Current diagnosis of acute and transient psychosis is based on:

   1. a aetiology

   2. b symptoms

   3. c prognosis

   4. d reliability

   5. e validity.

2. 2 Pathognomonic features of acute and transient psychoses include:

   1. a Schneider's first-rank symptoms of schizophrenia

   2. b shifting polymorphic symptoms

   3. c negative symptoms

   4. d confusion or perplexity

   5. e none of the above.

3. 3 The frequency of acute and transient psychoses per 1 000 00 population is estimated at:

   1. a 1–10

   2. b 10–20

   3. c 20–50

   4. d 50–100

   5. e >100.

4. 4 Factors associated with favourable outcome in acute and transient psychoses include:

   1. a onset within 4 weeks

   2. b female gender

   3. c precipitating stress

   4. d affective symptoms

   5. e family history of psychosis.

5. 5 Treatment and management of acute and transient psychoses is based on:

   1. a specific guidelines

   2. b NICE guidelines for psychosis and schizophrenia

   3. c first-episode psychosis guidelines

   4. d clinical experience

   5. e expert consensus.

MCQ answers

1

b

2

e

3

a

4

b

5

d