Part 1 reviewed the evidence for omega-3 supplementation in the treatment of depressed mood. This post concisely reviews the evidence for omega-3s in treating schizopohrenia, dementia, ADHD, PTSD and borderline personality disorder.
Omega-3s for symptoms of schizophrenia and other psychotic disorders
Augmentation with the omega-3 fatty acid EPA may be an effective preventive strategy in individuals at high risk for developing schizophrenia or in the early phase of psychotic illness but not as a treatment of established cases of schizophrenia. The neuroprotective role of omega-3s during the early so-called prodromal phase of schizophrenia may be related to general effects on the brain’s antioxidative intracellular defense mechanisms or direct interactions between EPA and the glutamate receptor system. EPA augmentation may be especially appropriate for younger or antipsychotic naïve individuals in the early phase of illness or cases in which metabolic or sexual adverse effects may result in poor medication adherence and symptomatic worsening. Limited findings suggest that a combination of EPA and DHA may reduce the rate of progression to full-blown schizophrenia in high-risk populations including individuals who chronically abuse substances or already have impairments in neuropsychological functioning. In contrast to positive findings of studies on EPA augmentation in the prodromal phase of schizophrenia, a meta-analysis of placebo controlled studies on EPA augmentation on symptom severity in patients with chronic schizophrenia or other psychotic disorders found no evidence for greater benefit of EPA augmentation over antipsychotic medications alone. All studies included in the meta-analysis lasted 12 weeks and used EPA doses between 2 and 3 g per day. Possible explanations of reported negative findings include small study size, absence of clinical efficacy of EPA supplementation in chronic schizophrenia, a “ceiling effect” on response to EPA augmentation associated with concurrent treatment with antipsychotics, combinations of different fatty acids may be more effective than EPA alone, and dietary differences and other socio-demographic factors that may have confounded findings.
DHA supplementation for treatment of cognitive decline and dementia
Systematic reviews and meta-analysis of studies on the effects of omega-3 supplementation on cognitive development, function, and decline throughout the life span concluded that omega-3 supplementation—especially DHA—may significantly improve cognitive development in infants but not in children, adolescents, adults, or the elderly. Omega-3 supplementation was not associated with a reduced rate of cognitive decline in healthy elderly adults or with a slowing in the rate of progression of Alzheimer disease.
Inconclusive evidence for omega-3s in ADHD
Although individual studies on omega-3s in ADHD report positive findings, a systematic review and meta-analysis of placebo-controlled trials on omega-3s in the treatment of ADHD in children and adolescents reported inconclusive findings due to methodological problems including small sample sizes, variability of selection criteria, and type and dosage of supplements and short-term follow-ups.
Recent studies have investigated the role of omega-3s in PTSD. These studies are based on the observation of increased rates of neuronal regeneration in the hippocampus soon following trauma. It is hypothesized that increased neuronal regeneration following trauma may result in more rapid clearance of fear memories and prevent immediate post-trauma memories from becoming long-term memories, reducing the risk of developing PTSD. In fact, animal studies support that omega-3 fatty acids increase hippocampal neurogenesis. Studies done in Japan following the 2011 tsunami investigated the effectiveness of pre-treatment with omega-3s in preventing the development of PTSD following exposure to trauma in first medical responders.
Symptoms of borderline personality disorder may improve with omega-3 supplementation
In a small, 8-week controlled trial (N = 30), women diagnosed with moderately severe borderline personality disorder randomized to ethyl-EPA (1 g per day) versus placebo reported less severe symptoms of aggression and depressed mood compared to the placebo group.
Omega-3s have few mild safety issues
Omega-3 fatty acids are generally well tolerated and pose few safety issues. Transient mild gastrointestinal distress is sometimes reported by patients who take omega-3 fatty acids. There is one case report of possible hypomania induced by omega-3 fatty acids. Rare cases of increased bleeding times have been reported in patients who take aspirin or anticoagulants together with omega-3s.