Psychiatric symptoms and disorders in phenylketonuria

Psychological and psychiatric problems are well documented across the lifespan of individuals with early-treated phenylketonuria (PKU). Early-treated children and adolescents tend to display attentional problems, school problems, lower achievement motivation, decreased social competence, decreased autonomy, and low-self-esteem. As they enter adulthood, early-treated individuals may carry forward low self-esteem and lack of autonomy but also tend to develop depressed mood, generalized anxiety, phobias, decreased positive emotions, social maturity deficits, and social isolation. The correlation between level of metabolic control and severity of symptoms suggests a biological basis of psychiatric dysfunction. Additionally, psychosocial factors such as the burden of living with a chronic illness may contribute to psychological and psychiatric outcomes in PKU. The lack of a PKU-specific psychiatric phenotype combined with the observation that not everyone with PKU is affected highlights the complexity of the problem. More research on psychiatric and psychological outcomes in PKU is required. Of particular importance is the routine monitoring of emotional, behavioral, and psychosocial symptoms in individuals with this metabolic disorder. Longitudinal studies are required to evaluate the impact of new and emerging therapies on psychiatric and psychosocial functioning in PKU. Unidentified or untreated emotional and behavioral symptoms may have a significant, lifelong impact on the quality of life and social status of patients.

The role of intelligence in phenylketonuria: a review of research and management

Phenylketonuria (PKU) results in profound intellectual disability in untreated individuals and more subtle cognitive deficits in individuals treated early and continuously. The assessment of intellectual functioning has been an important outcome variable and the focus of extensive research. Since the implementation of neonatal PKU screening programs in the 1960s, research on intellectual functioning in individuals with PKU has played a significant and positive role in guiding therapy and improving results. This is a literature review examining the relationship between intellectual outcome and treatment parameters including initiation of treatment, duration of treatment, and blood phenylalanine (Phe) levels from infancy through adulthood. While current PKU treatment practices have eliminated severe neurological and cognitive impairment, evidence suggests that intellectual functioning, although typically within the average range when PKU is treated early and continuously, may not be maximized under the current definition of well-controlled PKU, which is based on blood Phe levels. Future research assessing intellectual and neurocognitive outcome in PKU will enhance the development of new treatment strategies.

Neuropsychological outcome of subjects participating in the PKU adult collaborative study: a preliminary review

Adult subjects with classical phenylketonuria (PKU) who were diagnosed and treated neonatally participated in this long-term follow-up study. Twenty-four subjects received neuropsychological (NP) assessment and a subset received magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) to identify: (1) pattern of cognitive dysfunction; (2) effect of high blood phenylalanine (Phe) level at time of cognitive testing; and (3) treatment variables that may be associated with cognitive difficulties in adulthood. All subjects had average IQ except one subject in the borderline range. Diet was initiated by the 15th day of life. All subjects except one were on diet until age 6 years (mean years of treatment = 15). Blood Phe levels at cognitive testing ranged from 157 to 1713 micromol/L (mean = 1038); 11 subjects had levels < 1000 micromol/L and 13 subjects had levels >1000 micromol/L. Results suggest that adults with early-treated PKU demonstrate specific cognitive deficits, a number of which are associated with the frontal and temporal area of the brain. Deficits were noted in several domains including executive functioning, attention, verbal memory, expressive naming and verbal fluency. Self-report measures of depression and anxiety were generally in the normal/mild range. The group with a Phe level > 1000 micromol/L scored lower than the group with Phe level < 1000 micromol/L on measures of focused attention, verbal fluency, reaction time, verbal recognition memory, visual memory and naming. Tests of cognitive functioning were often correlated with measures of treatment during childhood rather than with Phe level at the time of cognitive testing. Subjects with abnormal MRI scored significantly lower on two cognitive tests (Trails A and CVLT Recognition Memory). We found no significant correlation between current brain Phe level obtained through MRS (n = 10) and neuropsychological functioning. Future longitudinal investigation with a larger sample size will assist in clarifying the aetiology of neuropsychological deficits and association with treatment history.

How well do standard clinical neuropsychological tests identify malingering? A preliminary analysis

Neuropsychological research has primarily focused on identification of malingerers through specialized tests designed for this purpose. Little attention has been given to the degree to which traditional clinical measures differentiate between malingerers and non-malingerers. This study examined the neuropsychological performance of 81 subjects who had a history of mild to moderate head injury, some of whom are believed to have been motivated to malinger their test performance. Subjects were classified as malingerers or non-malingerers based on their history as well as their performance on specific neuropsychological malingering tests. Performance on traditional neuropsychological clinical measures was examined for both groups. Results indicated that subjects' pattern of neuropsychological performance was not a reliable indicator of malingering performance, supporting the notion that specialized malingering tests are a critically necessary component to clinical classification of malingering. However, level of performance may provide an indication of malingering, as probable malingerers consistently performed worse on traditional and clinical neuropsychological measures. These findings are discussed in the context of the malingering literature.

Chronic Neuropsychological sequelae in a case of severe lithium intoxication

OBJECTIVE

This case provides data from serial assessments using a comprehensive neuropsychological test battery to assess the effects of severe toxicity on cognitive functioning, the pattern of deficits, and the regions of the brain that appear to be involved.

BACKGROUND

Lithium carbonate has made a significant contribution to the treatment of bipolar disorder, and considerable investigation has been conducted on both temporary and long-term side effects on the central nervous system. The effects of acute lithium intoxication on the central nervous system have been extensively documented.

METHOD

We studied a severe case of acute lithium intoxication and associated neuropsychological sequelae. The patient was evaluated twice with a comprehensive battery of neuropsychological tests within 2 years of the lithium intoxication.

RESULTS

Comprehensive neuropsychological evaluations indicated persistent cognitive sequelae, including impaired memory, attention, executive control functions, and visuospatial deficits.

CONCLUSIONS

The cognitive sequelae noted in the case of lithium toxicity are consistent with a subcortical dementia and the findings of other authors. Findings should be explored further in more rigorous clinical studies.